Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * autovacuum.c
4 : *
5 : * PostgreSQL Integrated Autovacuum Daemon
6 : *
7 : * The autovacuum system is structured in two different kinds of processes: the
8 : * autovacuum launcher and the autovacuum worker. The launcher is an
9 : * always-running process, started by the postmaster when the autovacuum GUC
10 : * parameter is set. The launcher schedules autovacuum workers to be started
11 : * when appropriate. The workers are the processes which execute the actual
12 : * vacuuming; they connect to a database as determined in the launcher, and
13 : * once connected they examine the catalogs to select the tables to vacuum.
14 : *
15 : * The autovacuum launcher cannot start the worker processes by itself,
16 : * because doing so would cause robustness issues (namely, failure to shut
17 : * them down on exceptional conditions, and also, since the launcher is
18 : * connected to shared memory and is thus subject to corruption there, it is
19 : * not as robust as the postmaster). So it leaves that task to the postmaster.
20 : *
21 : * There is an autovacuum shared memory area, where the launcher stores
22 : * information about the database it wants vacuumed. When it wants a new
23 : * worker to start, it sets a flag in shared memory and sends a signal to the
24 : * postmaster. Then postmaster knows nothing more than it must start a worker;
25 : * so it forks a new child, which turns into a worker. This new process
26 : * connects to shared memory, and there it can inspect the information that the
27 : * launcher has set up.
28 : *
29 : * If the fork() call fails in the postmaster, it sets a flag in the shared
30 : * memory area, and sends a signal to the launcher. The launcher, upon
31 : * noticing the flag, can try starting the worker again by resending the
32 : * signal. Note that the failure can only be transient (fork failure due to
33 : * high load, memory pressure, too many processes, etc); more permanent
34 : * problems, like failure to connect to a database, are detected later in the
35 : * worker and dealt with just by having the worker exit normally. The launcher
36 : * will launch a new worker again later, per schedule.
37 : *
38 : * When the worker is done vacuuming it sends SIGUSR2 to the launcher. The
39 : * launcher then wakes up and is able to launch another worker, if the schedule
40 : * is so tight that a new worker is needed immediately. At this time the
41 : * launcher can also balance the settings for the various remaining workers'
42 : * cost-based vacuum delay feature.
43 : *
44 : * Note that there can be more than one worker in a database concurrently.
45 : * They will store the table they are currently vacuuming in shared memory, so
46 : * that other workers avoid being blocked waiting for the vacuum lock for that
47 : * table. They will also fetch the last time the table was vacuumed from
48 : * pgstats just before vacuuming each table, to avoid vacuuming a table that
49 : * was just finished being vacuumed by another worker and thus is no longer
50 : * noted in shared memory. However, there is a small window (due to not yet
51 : * holding the relation lock) during which a worker may choose a table that was
52 : * already vacuumed; this is a bug in the current design.
53 : *
54 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
55 : * Portions Copyright (c) 1994, Regents of the University of California
56 : *
57 : *
58 : * IDENTIFICATION
59 : * src/backend/postmaster/autovacuum.c
60 : *
61 : *-------------------------------------------------------------------------
62 : */
63 : #include "postgres.h"
64 :
65 : #include <signal.h>
66 : #include <sys/time.h>
67 : #include <unistd.h>
68 :
69 : #include "access/heapam.h"
70 : #include "access/htup_details.h"
71 : #include "access/multixact.h"
72 : #include "access/reloptions.h"
73 : #include "access/tableam.h"
74 : #include "access/transam.h"
75 : #include "access/xact.h"
76 : #include "catalog/dependency.h"
77 : #include "catalog/namespace.h"
78 : #include "catalog/pg_database.h"
79 : #include "catalog/pg_namespace.h"
80 : #include "commands/vacuum.h"
81 : #include "common/int.h"
82 : #include "lib/ilist.h"
83 : #include "libpq/pqsignal.h"
84 : #include "miscadmin.h"
85 : #include "nodes/makefuncs.h"
86 : #include "pgstat.h"
87 : #include "postmaster/autovacuum.h"
88 : #include "postmaster/interrupt.h"
89 : #include "postmaster/postmaster.h"
90 : #include "storage/aio_subsys.h"
91 : #include "storage/bufmgr.h"
92 : #include "storage/ipc.h"
93 : #include "storage/latch.h"
94 : #include "storage/lmgr.h"
95 : #include "storage/pmsignal.h"
96 : #include "storage/proc.h"
97 : #include "storage/procsignal.h"
98 : #include "storage/smgr.h"
99 : #include "tcop/tcopprot.h"
100 : #include "utils/fmgroids.h"
101 : #include "utils/fmgrprotos.h"
102 : #include "utils/guc_hooks.h"
103 : #include "utils/injection_point.h"
104 : #include "utils/lsyscache.h"
105 : #include "utils/memutils.h"
106 : #include "utils/ps_status.h"
107 : #include "utils/rel.h"
108 : #include "utils/snapmgr.h"
109 : #include "utils/syscache.h"
110 : #include "utils/timeout.h"
111 : #include "utils/timestamp.h"
112 :
113 :
114 : /*
115 : * GUC parameters
116 : */
117 : bool autovacuum_start_daemon = false;
118 : int autovacuum_worker_slots;
119 : int autovacuum_max_workers;
120 : int autovacuum_work_mem = -1;
121 : int autovacuum_naptime;
122 : int autovacuum_vac_thresh;
123 : int autovacuum_vac_max_thresh;
124 : double autovacuum_vac_scale;
125 : int autovacuum_vac_ins_thresh;
126 : double autovacuum_vac_ins_scale;
127 : int autovacuum_anl_thresh;
128 : double autovacuum_anl_scale;
129 : int autovacuum_freeze_max_age;
130 : int autovacuum_multixact_freeze_max_age;
131 :
132 : double autovacuum_vac_cost_delay;
133 : int autovacuum_vac_cost_limit;
134 :
135 : int Log_autovacuum_min_duration = 600000;
136 : int Log_autoanalyze_min_duration = 600000;
137 :
138 : /* the minimum allowed time between two awakenings of the launcher */
139 : #define MIN_AUTOVAC_SLEEPTIME 100.0 /* milliseconds */
140 : #define MAX_AUTOVAC_SLEEPTIME 300 /* seconds */
141 :
142 : /*
143 : * Variables to save the cost-related storage parameters for the current
144 : * relation being vacuumed by this autovacuum worker. Using these, we can
145 : * ensure we don't overwrite the values of vacuum_cost_delay and
146 : * vacuum_cost_limit after reloading the configuration file. They are
147 : * initialized to "invalid" values to indicate that no cost-related storage
148 : * parameters were specified and will be set in do_autovacuum() after checking
149 : * the storage parameters in table_recheck_autovac().
150 : */
151 : static double av_storage_param_cost_delay = -1;
152 : static int av_storage_param_cost_limit = -1;
153 :
154 : /* Flags set by signal handlers */
155 : static volatile sig_atomic_t got_SIGUSR2 = false;
156 :
157 : /* Comparison points for determining whether freeze_max_age is exceeded */
158 : static TransactionId recentXid;
159 : static MultiXactId recentMulti;
160 :
161 : /* Default freeze ages to use for autovacuum (varies by database) */
162 : static int default_freeze_min_age;
163 : static int default_freeze_table_age;
164 : static int default_multixact_freeze_min_age;
165 : static int default_multixact_freeze_table_age;
166 :
167 : /* Memory context for long-lived data */
168 : static MemoryContext AutovacMemCxt;
169 :
170 : /* struct to keep track of databases in launcher */
171 : typedef struct avl_dbase
172 : {
173 : Oid adl_datid; /* hash key -- must be first */
174 : TimestampTz adl_next_worker;
175 : int adl_score;
176 : dlist_node adl_node;
177 : } avl_dbase;
178 :
179 : /* struct to keep track of databases in worker */
180 : typedef struct avw_dbase
181 : {
182 : Oid adw_datid;
183 : char *adw_name;
184 : TransactionId adw_frozenxid;
185 : MultiXactId adw_minmulti;
186 : PgStat_StatDBEntry *adw_entry;
187 : } avw_dbase;
188 :
189 : /* struct to keep track of tables to vacuum and/or analyze, in 1st pass */
190 : typedef struct av_relation
191 : {
192 : Oid ar_toastrelid; /* hash key - must be first */
193 : Oid ar_relid;
194 : bool ar_hasrelopts;
195 : AutoVacOpts ar_reloptions; /* copy of AutoVacOpts from the main table's
196 : * reloptions, or NULL if none */
197 : } av_relation;
198 :
199 : /* struct to keep track of tables to vacuum and/or analyze, after rechecking */
200 : typedef struct autovac_table
201 : {
202 : Oid at_relid;
203 : VacuumParams at_params;
204 : double at_storage_param_vac_cost_delay;
205 : int at_storage_param_vac_cost_limit;
206 : bool at_dobalance;
207 : bool at_sharedrel;
208 : char *at_relname;
209 : char *at_nspname;
210 : char *at_datname;
211 : } autovac_table;
212 :
213 : /*-------------
214 : * This struct holds information about a single worker's whereabouts. We keep
215 : * an array of these in shared memory, sized according to
216 : * autovacuum_worker_slots.
217 : *
218 : * wi_links entry into free list or running list
219 : * wi_dboid OID of the database this worker is supposed to work on
220 : * wi_tableoid OID of the table currently being vacuumed, if any
221 : * wi_sharedrel flag indicating whether table is marked relisshared
222 : * wi_proc pointer to PGPROC of the running worker, NULL if not started
223 : * wi_launchtime Time at which this worker was launched
224 : * wi_dobalance Whether this worker should be included in balance calculations
225 : *
226 : * All fields are protected by AutovacuumLock, except for wi_tableoid and
227 : * wi_sharedrel which are protected by AutovacuumScheduleLock (note these
228 : * two fields are read-only for everyone except that worker itself).
229 : *-------------
230 : */
231 : typedef struct WorkerInfoData
232 : {
233 : dlist_node wi_links;
234 : Oid wi_dboid;
235 : Oid wi_tableoid;
236 : PGPROC *wi_proc;
237 : TimestampTz wi_launchtime;
238 : pg_atomic_flag wi_dobalance;
239 : bool wi_sharedrel;
240 : } WorkerInfoData;
241 :
242 : typedef struct WorkerInfoData *WorkerInfo;
243 :
244 : /*
245 : * Possible signals received by the launcher from remote processes. These are
246 : * stored atomically in shared memory so that other processes can set them
247 : * without locking.
248 : */
249 : typedef enum
250 : {
251 : AutoVacForkFailed, /* failed trying to start a worker */
252 : AutoVacRebalance, /* rebalance the cost limits */
253 : } AutoVacuumSignal;
254 :
255 : #define AutoVacNumSignals (AutoVacRebalance + 1)
256 :
257 : /*
258 : * Autovacuum workitem array, stored in AutoVacuumShmem->av_workItems. This
259 : * list is mostly protected by AutovacuumLock, except that if an item is
260 : * marked 'active' other processes must not modify the work-identifying
261 : * members.
262 : */
263 : typedef struct AutoVacuumWorkItem
264 : {
265 : AutoVacuumWorkItemType avw_type;
266 : bool avw_used; /* below data is valid */
267 : bool avw_active; /* being processed */
268 : Oid avw_database;
269 : Oid avw_relation;
270 : BlockNumber avw_blockNumber;
271 : } AutoVacuumWorkItem;
272 :
273 : #define NUM_WORKITEMS 256
274 :
275 : /*-------------
276 : * The main autovacuum shmem struct. On shared memory we store this main
277 : * struct and the array of WorkerInfo structs. This struct keeps:
278 : *
279 : * av_signal set by other processes to indicate various conditions
280 : * av_launcherpid the PID of the autovacuum launcher
281 : * av_freeWorkers the WorkerInfo freelist
282 : * av_runningWorkers the WorkerInfo non-free queue
283 : * av_startingWorker pointer to WorkerInfo currently being started (cleared by
284 : * the worker itself as soon as it's up and running)
285 : * av_workItems work item array
286 : * av_nworkersForBalance the number of autovacuum workers to use when
287 : * calculating the per worker cost limit
288 : *
289 : * This struct is protected by AutovacuumLock, except for av_signal and parts
290 : * of the worker list (see above).
291 : *-------------
292 : */
293 : typedef struct
294 : {
295 : sig_atomic_t av_signal[AutoVacNumSignals];
296 : pid_t av_launcherpid;
297 : dclist_head av_freeWorkers;
298 : dlist_head av_runningWorkers;
299 : WorkerInfo av_startingWorker;
300 : AutoVacuumWorkItem av_workItems[NUM_WORKITEMS];
301 : pg_atomic_uint32 av_nworkersForBalance;
302 : } AutoVacuumShmemStruct;
303 :
304 : static AutoVacuumShmemStruct *AutoVacuumShmem;
305 :
306 : /*
307 : * the database list (of avl_dbase elements) in the launcher, and the context
308 : * that contains it
309 : */
310 : static dlist_head DatabaseList = DLIST_STATIC_INIT(DatabaseList);
311 : static MemoryContext DatabaseListCxt = NULL;
312 :
313 : /*
314 : * Dummy pointer to persuade Valgrind that we've not leaked the array of
315 : * avl_dbase structs. Make it global to ensure the compiler doesn't
316 : * optimize it away.
317 : */
318 : #ifdef USE_VALGRIND
319 : extern avl_dbase *avl_dbase_array;
320 : avl_dbase *avl_dbase_array;
321 : #endif
322 :
323 : /* Pointer to my own WorkerInfo, valid on each worker */
324 : static WorkerInfo MyWorkerInfo = NULL;
325 :
326 : /* PID of launcher, valid only in worker while shutting down */
327 : int AutovacuumLauncherPid = 0;
328 :
329 : static Oid do_start_worker(void);
330 : static void ProcessAutoVacLauncherInterrupts(void);
331 : pg_noreturn static void AutoVacLauncherShutdown(void);
332 : static void launcher_determine_sleep(bool canlaunch, bool recursing,
333 : struct timeval *nap);
334 : static void launch_worker(TimestampTz now);
335 : static List *get_database_list(void);
336 : static void rebuild_database_list(Oid newdb);
337 : static int db_comparator(const void *a, const void *b);
338 : static void autovac_recalculate_workers_for_balance(void);
339 :
340 : static void do_autovacuum(void);
341 : static void FreeWorkerInfo(int code, Datum arg);
342 :
343 : static autovac_table *table_recheck_autovac(Oid relid, HTAB *table_toast_map,
344 : TupleDesc pg_class_desc,
345 : int effective_multixact_freeze_max_age);
346 : static void recheck_relation_needs_vacanalyze(Oid relid, AutoVacOpts *avopts,
347 : Form_pg_class classForm,
348 : int effective_multixact_freeze_max_age,
349 : bool *dovacuum, bool *doanalyze, bool *wraparound);
350 : static void relation_needs_vacanalyze(Oid relid, AutoVacOpts *relopts,
351 : Form_pg_class classForm,
352 : PgStat_StatTabEntry *tabentry,
353 : int effective_multixact_freeze_max_age,
354 : bool *dovacuum, bool *doanalyze, bool *wraparound);
355 :
356 : static void autovacuum_do_vac_analyze(autovac_table *tab,
357 : BufferAccessStrategy bstrategy);
358 : static AutoVacOpts *extract_autovac_opts(HeapTuple tup,
359 : TupleDesc pg_class_desc);
360 : static void perform_work_item(AutoVacuumWorkItem *workitem);
361 : static void autovac_report_activity(autovac_table *tab);
362 : static void autovac_report_workitem(AutoVacuumWorkItem *workitem,
363 : const char *nspname, const char *relname);
364 : static void avl_sigusr2_handler(SIGNAL_ARGS);
365 : static bool av_worker_available(void);
366 : static void check_av_worker_gucs(void);
367 :
368 :
369 :
370 : /********************************************************************
371 : * AUTOVACUUM LAUNCHER CODE
372 : ********************************************************************/
373 :
374 : /*
375 : * Main entry point for the autovacuum launcher process.
376 : */
377 : void
378 790 : AutoVacLauncherMain(const void *startup_data, size_t startup_data_len)
379 : {
380 : sigjmp_buf local_sigjmp_buf;
381 :
382 : Assert(startup_data_len == 0);
383 :
384 : /* Release postmaster's working memory context */
385 790 : if (PostmasterContext)
386 : {
387 790 : MemoryContextDelete(PostmasterContext);
388 790 : PostmasterContext = NULL;
389 : }
390 :
391 790 : MyBackendType = B_AUTOVAC_LAUNCHER;
392 790 : init_ps_display(NULL);
393 :
394 790 : ereport(DEBUG1,
395 : (errmsg_internal("autovacuum launcher started")));
396 :
397 790 : if (PostAuthDelay)
398 0 : pg_usleep(PostAuthDelay * 1000000L);
399 :
400 : Assert(GetProcessingMode() == InitProcessing);
401 :
402 : /*
403 : * Set up signal handlers. We operate on databases much like a regular
404 : * backend, so we use the same signal handling. See equivalent code in
405 : * tcop/postgres.c.
406 : */
407 790 : pqsignal(SIGHUP, SignalHandlerForConfigReload);
408 790 : pqsignal(SIGINT, StatementCancelHandler);
409 790 : pqsignal(SIGTERM, SignalHandlerForShutdownRequest);
410 : /* SIGQUIT handler was already set up by InitPostmasterChild */
411 :
412 790 : InitializeTimeouts(); /* establishes SIGALRM handler */
413 :
414 790 : pqsignal(SIGPIPE, SIG_IGN);
415 790 : pqsignal(SIGUSR1, procsignal_sigusr1_handler);
416 790 : pqsignal(SIGUSR2, avl_sigusr2_handler);
417 790 : pqsignal(SIGFPE, FloatExceptionHandler);
418 790 : pqsignal(SIGCHLD, SIG_DFL);
419 :
420 : /*
421 : * Create a per-backend PGPROC struct in shared memory. We must do this
422 : * before we can use LWLocks or access any shared memory.
423 : */
424 790 : InitProcess();
425 :
426 : /* Early initialization */
427 790 : BaseInit();
428 :
429 790 : InitPostgres(NULL, InvalidOid, NULL, InvalidOid, 0, NULL);
430 :
431 790 : SetProcessingMode(NormalProcessing);
432 :
433 : /*
434 : * Create a memory context that we will do all our work in. We do this so
435 : * that we can reset the context during error recovery and thereby avoid
436 : * possible memory leaks.
437 : */
438 790 : AutovacMemCxt = AllocSetContextCreate(TopMemoryContext,
439 : "Autovacuum Launcher",
440 : ALLOCSET_DEFAULT_SIZES);
441 790 : MemoryContextSwitchTo(AutovacMemCxt);
442 :
443 : /*
444 : * If an exception is encountered, processing resumes here.
445 : *
446 : * This code is a stripped down version of PostgresMain error recovery.
447 : *
448 : * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
449 : * (to wit, BlockSig) will be restored when longjmp'ing to here. Thus,
450 : * signals other than SIGQUIT will be blocked until we complete error
451 : * recovery. It might seem that this policy makes the HOLD_INTERRUPTS()
452 : * call redundant, but it is not since InterruptPending might be set
453 : * already.
454 : */
455 790 : if (sigsetjmp(local_sigjmp_buf, 1) != 0)
456 : {
457 : /* since not using PG_TRY, must reset error stack by hand */
458 0 : error_context_stack = NULL;
459 :
460 : /* Prevents interrupts while cleaning up */
461 0 : HOLD_INTERRUPTS();
462 :
463 : /* Forget any pending QueryCancel or timeout request */
464 0 : disable_all_timeouts(false);
465 0 : QueryCancelPending = false; /* second to avoid race condition */
466 :
467 : /* Report the error to the server log */
468 0 : EmitErrorReport();
469 :
470 : /* Abort the current transaction in order to recover */
471 0 : AbortCurrentTransaction();
472 :
473 : /*
474 : * Release any other resources, for the case where we were not in a
475 : * transaction.
476 : */
477 0 : LWLockReleaseAll();
478 0 : pgstat_report_wait_end();
479 0 : pgaio_error_cleanup();
480 0 : UnlockBuffers();
481 : /* this is probably dead code, but let's be safe: */
482 0 : if (AuxProcessResourceOwner)
483 0 : ReleaseAuxProcessResources(false);
484 0 : AtEOXact_Buffers(false);
485 0 : AtEOXact_SMgr();
486 0 : AtEOXact_Files(false);
487 0 : AtEOXact_HashTables(false);
488 :
489 : /*
490 : * Now return to normal top-level context and clear ErrorContext for
491 : * next time.
492 : */
493 0 : MemoryContextSwitchTo(AutovacMemCxt);
494 0 : FlushErrorState();
495 :
496 : /* Flush any leaked data in the top-level context */
497 0 : MemoryContextReset(AutovacMemCxt);
498 :
499 : /* don't leave dangling pointers to freed memory */
500 0 : DatabaseListCxt = NULL;
501 0 : dlist_init(&DatabaseList);
502 :
503 : /* Now we can allow interrupts again */
504 0 : RESUME_INTERRUPTS();
505 :
506 : /* if in shutdown mode, no need for anything further; just go away */
507 0 : if (ShutdownRequestPending)
508 0 : AutoVacLauncherShutdown();
509 :
510 : /*
511 : * Sleep at least 1 second after any error. We don't want to be
512 : * filling the error logs as fast as we can.
513 : */
514 0 : pg_usleep(1000000L);
515 : }
516 :
517 : /* We can now handle ereport(ERROR) */
518 790 : PG_exception_stack = &local_sigjmp_buf;
519 :
520 : /* must unblock signals before calling rebuild_database_list */
521 790 : sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
522 :
523 : /*
524 : * Set always-secure search path. Launcher doesn't connect to a database,
525 : * so this has no effect.
526 : */
527 790 : SetConfigOption("search_path", "", PGC_SUSET, PGC_S_OVERRIDE);
528 :
529 : /*
530 : * Force zero_damaged_pages OFF in the autovac process, even if it is set
531 : * in postgresql.conf. We don't really want such a dangerous option being
532 : * applied non-interactively.
533 : */
534 790 : SetConfigOption("zero_damaged_pages", "false", PGC_SUSET, PGC_S_OVERRIDE);
535 :
536 : /*
537 : * Force settable timeouts off to avoid letting these settings prevent
538 : * regular maintenance from being executed.
539 : */
540 790 : SetConfigOption("statement_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
541 790 : SetConfigOption("transaction_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
542 790 : SetConfigOption("lock_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
543 790 : SetConfigOption("idle_in_transaction_session_timeout", "0",
544 : PGC_SUSET, PGC_S_OVERRIDE);
545 :
546 : /*
547 : * Force default_transaction_isolation to READ COMMITTED. We don't want
548 : * to pay the overhead of serializable mode, nor add any risk of causing
549 : * deadlocks or delaying other transactions.
550 : */
551 790 : SetConfigOption("default_transaction_isolation", "read committed",
552 : PGC_SUSET, PGC_S_OVERRIDE);
553 :
554 : /*
555 : * Even when system is configured to use a different fetch consistency,
556 : * for autovac we always want fresh stats.
557 : */
558 790 : SetConfigOption("stats_fetch_consistency", "none", PGC_SUSET, PGC_S_OVERRIDE);
559 :
560 : /*
561 : * In emergency mode, just start a worker (unless shutdown was requested)
562 : * and go away.
563 : */
564 790 : if (!AutoVacuumingActive())
565 : {
566 0 : if (!ShutdownRequestPending)
567 0 : do_start_worker();
568 0 : proc_exit(0); /* done */
569 : }
570 :
571 790 : AutoVacuumShmem->av_launcherpid = MyProcPid;
572 :
573 : /*
574 : * Create the initial database list. The invariant we want this list to
575 : * keep is that it's ordered by decreasing next_worker. As soon as an
576 : * entry is updated to a higher time, it will be moved to the front (which
577 : * is correct because the only operation is to add autovacuum_naptime to
578 : * the entry, and time always increases).
579 : */
580 790 : rebuild_database_list(InvalidOid);
581 :
582 : /* loop until shutdown request */
583 15442 : while (!ShutdownRequestPending)
584 : {
585 : struct timeval nap;
586 15436 : TimestampTz current_time = 0;
587 : bool can_launch;
588 :
589 : /*
590 : * This loop is a bit different from the normal use of WaitLatch,
591 : * because we'd like to sleep before the first launch of a child
592 : * process. So it's WaitLatch, then ResetLatch, then check for
593 : * wakening conditions.
594 : */
595 :
596 15436 : launcher_determine_sleep(av_worker_available(), false, &nap);
597 :
598 : /*
599 : * Wait until naptime expires or we get some type of signal (all the
600 : * signal handlers will wake us by calling SetLatch).
601 : */
602 15436 : (void) WaitLatch(MyLatch,
603 : WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
604 15436 : (nap.tv_sec * 1000L) + (nap.tv_usec / 1000L),
605 : WAIT_EVENT_AUTOVACUUM_MAIN);
606 :
607 15430 : ResetLatch(MyLatch);
608 :
609 15430 : ProcessAutoVacLauncherInterrupts();
610 :
611 : /*
612 : * a worker finished, or postmaster signaled failure to start a worker
613 : */
614 14652 : if (got_SIGUSR2)
615 : {
616 8634 : got_SIGUSR2 = false;
617 :
618 : /* rebalance cost limits, if needed */
619 8634 : if (AutoVacuumShmem->av_signal[AutoVacRebalance])
620 : {
621 4314 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
622 4314 : AutoVacuumShmem->av_signal[AutoVacRebalance] = false;
623 4314 : autovac_recalculate_workers_for_balance();
624 4314 : LWLockRelease(AutovacuumLock);
625 : }
626 :
627 8634 : if (AutoVacuumShmem->av_signal[AutoVacForkFailed])
628 : {
629 : /*
630 : * If the postmaster failed to start a new worker, we sleep
631 : * for a little while and resend the signal. The new worker's
632 : * state is still in memory, so this is sufficient. After
633 : * that, we restart the main loop.
634 : *
635 : * XXX should we put a limit to the number of times we retry?
636 : * I don't think it makes much sense, because a future start
637 : * of a worker will continue to fail in the same way.
638 : */
639 0 : AutoVacuumShmem->av_signal[AutoVacForkFailed] = false;
640 0 : pg_usleep(1000000L); /* 1s */
641 0 : SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER);
642 4656 : continue;
643 : }
644 : }
645 :
646 : /*
647 : * There are some conditions that we need to check before trying to
648 : * start a worker. First, we need to make sure that there is a worker
649 : * slot available. Second, we need to make sure that no other worker
650 : * failed while starting up.
651 : */
652 :
653 14652 : current_time = GetCurrentTimestamp();
654 14652 : LWLockAcquire(AutovacuumLock, LW_SHARED);
655 :
656 14652 : can_launch = av_worker_available();
657 :
658 14652 : if (AutoVacuumShmem->av_startingWorker != NULL)
659 : {
660 : int waittime;
661 96 : WorkerInfo worker = AutoVacuumShmem->av_startingWorker;
662 :
663 : /*
664 : * We can't launch another worker when another one is still
665 : * starting up (or failed while doing so), so just sleep for a bit
666 : * more; that worker will wake us up again as soon as it's ready.
667 : * We will only wait autovacuum_naptime seconds (up to a maximum
668 : * of 60 seconds) for this to happen however. Note that failure
669 : * to connect to a particular database is not a problem here,
670 : * because the worker removes itself from the startingWorker
671 : * pointer before trying to connect. Problems detected by the
672 : * postmaster (like fork() failure) are also reported and handled
673 : * differently. The only problems that may cause this code to
674 : * fire are errors in the earlier sections of AutoVacWorkerMain,
675 : * before the worker removes the WorkerInfo from the
676 : * startingWorker pointer.
677 : */
678 96 : waittime = Min(autovacuum_naptime, 60) * 1000;
679 96 : if (TimestampDifferenceExceeds(worker->wi_launchtime, current_time,
680 : waittime))
681 : {
682 0 : LWLockRelease(AutovacuumLock);
683 0 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
684 :
685 : /*
686 : * No other process can put a worker in starting mode, so if
687 : * startingWorker is still INVALID after exchanging our lock,
688 : * we assume it's the same one we saw above (so we don't
689 : * recheck the launch time).
690 : */
691 0 : if (AutoVacuumShmem->av_startingWorker != NULL)
692 : {
693 0 : worker = AutoVacuumShmem->av_startingWorker;
694 0 : worker->wi_dboid = InvalidOid;
695 0 : worker->wi_tableoid = InvalidOid;
696 0 : worker->wi_sharedrel = false;
697 0 : worker->wi_proc = NULL;
698 0 : worker->wi_launchtime = 0;
699 0 : dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
700 : &worker->wi_links);
701 0 : AutoVacuumShmem->av_startingWorker = NULL;
702 0 : ereport(WARNING,
703 : errmsg("autovacuum worker took too long to start; canceled"));
704 : }
705 : }
706 : else
707 96 : can_launch = false;
708 : }
709 14652 : LWLockRelease(AutovacuumLock); /* either shared or exclusive */
710 :
711 : /* if we can't do anything, just go back to sleep */
712 14652 : if (!can_launch)
713 4656 : continue;
714 :
715 : /* We're OK to start a new worker */
716 :
717 9996 : if (dlist_is_empty(&DatabaseList))
718 : {
719 : /*
720 : * Special case when the list is empty: start a worker right away.
721 : * This covers the initial case, when no database is in pgstats
722 : * (thus the list is empty). Note that the constraints in
723 : * launcher_determine_sleep keep us from starting workers too
724 : * quickly (at most once every autovacuum_naptime when the list is
725 : * empty).
726 : */
727 12 : launch_worker(current_time);
728 : }
729 : else
730 : {
731 : /*
732 : * because rebuild_database_list constructs a list with most
733 : * distant adl_next_worker first, we obtain our database from the
734 : * tail of the list.
735 : */
736 : avl_dbase *avdb;
737 :
738 9984 : avdb = dlist_tail_element(avl_dbase, adl_node, &DatabaseList);
739 :
740 : /*
741 : * launch a worker if next_worker is right now or it is in the
742 : * past
743 : */
744 9984 : if (TimestampDifferenceExceeds(avdb->adl_next_worker,
745 : current_time, 0))
746 4322 : launch_worker(current_time);
747 : }
748 : }
749 :
750 6 : AutoVacLauncherShutdown();
751 : }
752 :
753 : /*
754 : * Process any new interrupts.
755 : */
756 : static void
757 15430 : ProcessAutoVacLauncherInterrupts(void)
758 : {
759 : /* the normal shutdown case */
760 15430 : if (ShutdownRequestPending)
761 778 : AutoVacLauncherShutdown();
762 :
763 14652 : if (ConfigReloadPending)
764 : {
765 72 : int autovacuum_max_workers_prev = autovacuum_max_workers;
766 :
767 72 : ConfigReloadPending = false;
768 72 : ProcessConfigFile(PGC_SIGHUP);
769 :
770 : /* shutdown requested in config file? */
771 72 : if (!AutoVacuumingActive())
772 0 : AutoVacLauncherShutdown();
773 :
774 : /*
775 : * If autovacuum_max_workers changed, emit a WARNING if
776 : * autovacuum_worker_slots < autovacuum_max_workers. If it didn't
777 : * change, skip this to avoid too many repeated log messages.
778 : */
779 72 : if (autovacuum_max_workers_prev != autovacuum_max_workers)
780 0 : check_av_worker_gucs();
781 :
782 : /* rebuild the list in case the naptime changed */
783 72 : rebuild_database_list(InvalidOid);
784 : }
785 :
786 : /* Process barrier events */
787 14652 : if (ProcSignalBarrierPending)
788 60 : ProcessProcSignalBarrier();
789 :
790 : /* Perform logging of memory contexts of this process */
791 14652 : if (LogMemoryContextPending)
792 0 : ProcessLogMemoryContextInterrupt();
793 :
794 : /* Process sinval catchup interrupts that happened while sleeping */
795 14652 : ProcessCatchupInterrupt();
796 14652 : }
797 :
798 : /*
799 : * Perform a normal exit from the autovac launcher.
800 : */
801 : static void
802 784 : AutoVacLauncherShutdown(void)
803 : {
804 784 : ereport(DEBUG1,
805 : (errmsg_internal("autovacuum launcher shutting down")));
806 784 : AutoVacuumShmem->av_launcherpid = 0;
807 :
808 784 : proc_exit(0); /* done */
809 : }
810 :
811 : /*
812 : * Determine the time to sleep, based on the database list.
813 : *
814 : * The "canlaunch" parameter indicates whether we can start a worker right now,
815 : * for example due to the workers being all busy. If this is false, we will
816 : * cause a long sleep, which will be interrupted when a worker exits.
817 : */
818 : static void
819 15628 : launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval *nap)
820 : {
821 : /*
822 : * We sleep until the next scheduled vacuum. We trust that when the
823 : * database list was built, care was taken so that no entries have times
824 : * in the past; if the first entry has too close a next_worker value, or a
825 : * time in the past, we will sleep a small nominal time.
826 : */
827 15628 : if (!canlaunch)
828 : {
829 8582 : nap->tv_sec = autovacuum_naptime;
830 8582 : nap->tv_usec = 0;
831 : }
832 7046 : else if (!dlist_is_empty(&DatabaseList))
833 : {
834 6996 : TimestampTz current_time = GetCurrentTimestamp();
835 : TimestampTz next_wakeup;
836 : avl_dbase *avdb;
837 : long secs;
838 : int usecs;
839 :
840 6996 : avdb = dlist_tail_element(avl_dbase, adl_node, &DatabaseList);
841 :
842 6996 : next_wakeup = avdb->adl_next_worker;
843 6996 : TimestampDifference(current_time, next_wakeup, &secs, &usecs);
844 :
845 6996 : nap->tv_sec = secs;
846 6996 : nap->tv_usec = usecs;
847 : }
848 : else
849 : {
850 : /* list is empty, sleep for whole autovacuum_naptime seconds */
851 50 : nap->tv_sec = autovacuum_naptime;
852 50 : nap->tv_usec = 0;
853 : }
854 :
855 : /*
856 : * If the result is exactly zero, it means a database had an entry with
857 : * time in the past. Rebuild the list so that the databases are evenly
858 : * distributed again, and recalculate the time to sleep. This can happen
859 : * if there are more tables needing vacuum than workers, and they all take
860 : * longer to vacuum than autovacuum_naptime.
861 : *
862 : * We only recurse once. rebuild_database_list should always return times
863 : * in the future, but it seems best not to trust too much on that.
864 : */
865 15628 : if (nap->tv_sec == 0 && nap->tv_usec == 0 && !recursing)
866 : {
867 192 : rebuild_database_list(InvalidOid);
868 192 : launcher_determine_sleep(canlaunch, true, nap);
869 192 : return;
870 : }
871 :
872 : /* The smallest time we'll allow the launcher to sleep. */
873 15436 : if (nap->tv_sec <= 0 && nap->tv_usec <= MIN_AUTOVAC_SLEEPTIME * 1000)
874 : {
875 1390 : nap->tv_sec = 0;
876 1390 : nap->tv_usec = MIN_AUTOVAC_SLEEPTIME * 1000;
877 : }
878 :
879 : /*
880 : * If the sleep time is too large, clamp it to an arbitrary maximum (plus
881 : * any fractional seconds, for simplicity). This avoids an essentially
882 : * infinite sleep in strange cases like the system clock going backwards a
883 : * few years.
884 : */
885 15436 : if (nap->tv_sec > MAX_AUTOVAC_SLEEPTIME)
886 18 : nap->tv_sec = MAX_AUTOVAC_SLEEPTIME;
887 : }
888 :
889 : /*
890 : * Build an updated DatabaseList. It must only contain databases that appear
891 : * in pgstats, and must be sorted by next_worker from highest to lowest,
892 : * distributed regularly across the next autovacuum_naptime interval.
893 : *
894 : * Receives the Oid of the database that made this list be generated (we call
895 : * this the "new" database, because when the database was already present on
896 : * the list, we expect that this function is not called at all). The
897 : * preexisting list, if any, will be used to preserve the order of the
898 : * databases in the autovacuum_naptime period. The new database is put at the
899 : * end of the interval. The actual values are not saved, which should not be
900 : * much of a problem.
901 : */
902 : static void
903 1084 : rebuild_database_list(Oid newdb)
904 : {
905 : List *dblist;
906 : ListCell *cell;
907 : MemoryContext newcxt;
908 : MemoryContext oldcxt;
909 : MemoryContext tmpcxt;
910 : HASHCTL hctl;
911 : int score;
912 : int nelems;
913 : HTAB *dbhash;
914 : dlist_iter iter;
915 :
916 1084 : newcxt = AllocSetContextCreate(AutovacMemCxt,
917 : "Autovacuum database list",
918 : ALLOCSET_DEFAULT_SIZES);
919 1084 : tmpcxt = AllocSetContextCreate(newcxt,
920 : "Autovacuum database list (tmp)",
921 : ALLOCSET_DEFAULT_SIZES);
922 1084 : oldcxt = MemoryContextSwitchTo(tmpcxt);
923 :
924 : /*
925 : * Implementing this is not as simple as it sounds, because we need to put
926 : * the new database at the end of the list; next the databases that were
927 : * already on the list, and finally (at the tail of the list) all the
928 : * other databases that are not on the existing list.
929 : *
930 : * To do this, we build an empty hash table of scored databases. We will
931 : * start with the lowest score (zero) for the new database, then
932 : * increasing scores for the databases in the existing list, in order, and
933 : * lastly increasing scores for all databases gotten via
934 : * get_database_list() that are not already on the hash.
935 : *
936 : * Then we will put all the hash elements into an array, sort the array by
937 : * score, and finally put the array elements into the new doubly linked
938 : * list.
939 : */
940 1084 : hctl.keysize = sizeof(Oid);
941 1084 : hctl.entrysize = sizeof(avl_dbase);
942 1084 : hctl.hcxt = tmpcxt;
943 1084 : dbhash = hash_create("autovacuum db hash", 20, &hctl, /* magic number here
944 : * FIXME */
945 : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
946 :
947 : /* start by inserting the new database */
948 1084 : score = 0;
949 1084 : if (OidIsValid(newdb))
950 : {
951 : avl_dbase *db;
952 : PgStat_StatDBEntry *entry;
953 :
954 : /* only consider this database if it has a pgstat entry */
955 30 : entry = pgstat_fetch_stat_dbentry(newdb);
956 30 : if (entry != NULL)
957 : {
958 : /* we assume it isn't found because the hash was just created */
959 24 : db = hash_search(dbhash, &newdb, HASH_ENTER, NULL);
960 :
961 : /* hash_search already filled in the key */
962 24 : db->adl_score = score++;
963 : /* next_worker is filled in later */
964 : }
965 : }
966 :
967 : /* Now insert the databases from the existing list */
968 1808 : dlist_foreach(iter, &DatabaseList)
969 : {
970 724 : avl_dbase *avdb = dlist_container(avl_dbase, adl_node, iter.cur);
971 : avl_dbase *db;
972 : bool found;
973 : PgStat_StatDBEntry *entry;
974 :
975 : /*
976 : * skip databases with no stat entries -- in particular, this gets rid
977 : * of dropped databases
978 : */
979 724 : entry = pgstat_fetch_stat_dbentry(avdb->adl_datid);
980 724 : if (entry == NULL)
981 0 : continue;
982 :
983 724 : db = hash_search(dbhash, &(avdb->adl_datid), HASH_ENTER, &found);
984 :
985 724 : if (!found)
986 : {
987 : /* hash_search already filled in the key */
988 724 : db->adl_score = score++;
989 : /* next_worker is filled in later */
990 : }
991 : }
992 :
993 : /* finally, insert all qualifying databases not previously inserted */
994 1084 : dblist = get_database_list();
995 4656 : foreach(cell, dblist)
996 : {
997 3572 : avw_dbase *avdb = lfirst(cell);
998 : avl_dbase *db;
999 : bool found;
1000 : PgStat_StatDBEntry *entry;
1001 :
1002 : /* only consider databases with a pgstat entry */
1003 3572 : entry = pgstat_fetch_stat_dbentry(avdb->adw_datid);
1004 3572 : if (entry == NULL)
1005 1704 : continue;
1006 :
1007 1868 : db = hash_search(dbhash, &(avdb->adw_datid), HASH_ENTER, &found);
1008 : /* only update the score if the database was not already on the hash */
1009 1868 : if (!found)
1010 : {
1011 : /* hash_search already filled in the key */
1012 1120 : db->adl_score = score++;
1013 : /* next_worker is filled in later */
1014 : }
1015 : }
1016 1084 : nelems = score;
1017 :
1018 : /* from here on, the allocated memory belongs to the new list */
1019 1084 : MemoryContextSwitchTo(newcxt);
1020 1084 : dlist_init(&DatabaseList);
1021 :
1022 1084 : if (nelems > 0)
1023 : {
1024 : TimestampTz current_time;
1025 : int millis_increment;
1026 : avl_dbase *dbary;
1027 : avl_dbase *db;
1028 : HASH_SEQ_STATUS seq;
1029 : int i;
1030 :
1031 : /* put all the hash elements into an array */
1032 1046 : dbary = palloc(nelems * sizeof(avl_dbase));
1033 : /* keep Valgrind quiet */
1034 : #ifdef USE_VALGRIND
1035 : avl_dbase_array = dbary;
1036 : #endif
1037 :
1038 1046 : i = 0;
1039 1046 : hash_seq_init(&seq, dbhash);
1040 2914 : while ((db = hash_seq_search(&seq)) != NULL)
1041 1868 : memcpy(&(dbary[i++]), db, sizeof(avl_dbase));
1042 :
1043 : /* sort the array */
1044 1046 : qsort(dbary, nelems, sizeof(avl_dbase), db_comparator);
1045 :
1046 : /*
1047 : * Determine the time interval between databases in the schedule. If
1048 : * we see that the configured naptime would take us to sleep times
1049 : * lower than our min sleep time (which launcher_determine_sleep is
1050 : * coded not to allow), silently use a larger naptime (but don't touch
1051 : * the GUC variable).
1052 : */
1053 1046 : millis_increment = 1000.0 * autovacuum_naptime / nelems;
1054 1046 : if (millis_increment <= MIN_AUTOVAC_SLEEPTIME)
1055 0 : millis_increment = MIN_AUTOVAC_SLEEPTIME * 1.1;
1056 :
1057 1046 : current_time = GetCurrentTimestamp();
1058 :
1059 : /*
1060 : * move the elements from the array into the dlist, setting the
1061 : * next_worker while walking the array
1062 : */
1063 2914 : for (i = 0; i < nelems; i++)
1064 : {
1065 1868 : db = &(dbary[i]);
1066 :
1067 1868 : current_time = TimestampTzPlusMilliseconds(current_time,
1068 : millis_increment);
1069 1868 : db->adl_next_worker = current_time;
1070 :
1071 : /* later elements should go closer to the head of the list */
1072 1868 : dlist_push_head(&DatabaseList, &db->adl_node);
1073 : }
1074 : }
1075 :
1076 : /* all done, clean up memory */
1077 1084 : if (DatabaseListCxt != NULL)
1078 294 : MemoryContextDelete(DatabaseListCxt);
1079 1084 : MemoryContextDelete(tmpcxt);
1080 1084 : DatabaseListCxt = newcxt;
1081 1084 : MemoryContextSwitchTo(oldcxt);
1082 1084 : }
1083 :
1084 : /* qsort comparator for avl_dbase, using adl_score */
1085 : static int
1086 1178 : db_comparator(const void *a, const void *b)
1087 : {
1088 2356 : return pg_cmp_s32(((const avl_dbase *) a)->adl_score,
1089 1178 : ((const avl_dbase *) b)->adl_score);
1090 : }
1091 :
1092 : /*
1093 : * do_start_worker
1094 : *
1095 : * Bare-bones procedure for starting an autovacuum worker from the launcher.
1096 : * It determines what database to work on, sets up shared memory stuff and
1097 : * signals postmaster to start the worker. It fails gracefully if invoked when
1098 : * autovacuum_workers are already active.
1099 : *
1100 : * Return value is the OID of the database that the worker is going to process,
1101 : * or InvalidOid if no worker was actually started.
1102 : */
1103 : static Oid
1104 4334 : do_start_worker(void)
1105 : {
1106 : List *dblist;
1107 : ListCell *cell;
1108 : TransactionId xidForceLimit;
1109 : MultiXactId multiForceLimit;
1110 : bool for_xid_wrap;
1111 : bool for_multi_wrap;
1112 : avw_dbase *avdb;
1113 : TimestampTz current_time;
1114 4334 : bool skipit = false;
1115 4334 : Oid retval = InvalidOid;
1116 : MemoryContext tmpcxt,
1117 : oldcxt;
1118 :
1119 : /* return quickly when there are no free workers */
1120 4334 : LWLockAcquire(AutovacuumLock, LW_SHARED);
1121 4334 : if (!av_worker_available())
1122 : {
1123 0 : LWLockRelease(AutovacuumLock);
1124 0 : return InvalidOid;
1125 : }
1126 4334 : LWLockRelease(AutovacuumLock);
1127 :
1128 : /*
1129 : * Create and switch to a temporary context to avoid leaking the memory
1130 : * allocated for the database list.
1131 : */
1132 4334 : tmpcxt = AllocSetContextCreate(CurrentMemoryContext,
1133 : "Autovacuum start worker (tmp)",
1134 : ALLOCSET_DEFAULT_SIZES);
1135 4334 : oldcxt = MemoryContextSwitchTo(tmpcxt);
1136 :
1137 : /* Get a list of databases */
1138 4334 : dblist = get_database_list();
1139 :
1140 : /*
1141 : * Determine the oldest datfrozenxid/relfrozenxid that we will allow to
1142 : * pass without forcing a vacuum. (This limit can be tightened for
1143 : * particular tables, but not loosened.)
1144 : */
1145 4334 : recentXid = ReadNextTransactionId();
1146 4334 : xidForceLimit = recentXid - autovacuum_freeze_max_age;
1147 : /* ensure it's a "normal" XID, else TransactionIdPrecedes misbehaves */
1148 : /* this can cause the limit to go backwards by 3, but that's OK */
1149 4334 : if (xidForceLimit < FirstNormalTransactionId)
1150 0 : xidForceLimit -= FirstNormalTransactionId;
1151 :
1152 : /* Also determine the oldest datminmxid we will consider. */
1153 4334 : recentMulti = ReadNextMultiXactId();
1154 4334 : multiForceLimit = recentMulti - MultiXactMemberFreezeThreshold();
1155 4334 : if (multiForceLimit < FirstMultiXactId)
1156 0 : multiForceLimit -= FirstMultiXactId;
1157 :
1158 : /*
1159 : * Choose a database to connect to. We pick the database that was least
1160 : * recently auto-vacuumed, or one that needs vacuuming to prevent Xid
1161 : * wraparound-related data loss. If any db at risk of Xid wraparound is
1162 : * found, we pick the one with oldest datfrozenxid, independently of
1163 : * autovacuum times; similarly we pick the one with the oldest datminmxid
1164 : * if any is in MultiXactId wraparound. Note that those in Xid wraparound
1165 : * danger are given more priority than those in multi wraparound danger.
1166 : *
1167 : * Note that a database with no stats entry is not considered, except for
1168 : * Xid wraparound purposes. The theory is that if no one has ever
1169 : * connected to it since the stats were last initialized, it doesn't need
1170 : * vacuuming.
1171 : *
1172 : * XXX This could be improved if we had more info about whether it needs
1173 : * vacuuming before connecting to it. Perhaps look through the pgstats
1174 : * data for the database's tables? One idea is to keep track of the
1175 : * number of new and dead tuples per database in pgstats. However it
1176 : * isn't clear how to construct a metric that measures that and not cause
1177 : * starvation for less busy databases.
1178 : */
1179 4334 : avdb = NULL;
1180 4334 : for_xid_wrap = false;
1181 4334 : for_multi_wrap = false;
1182 4334 : current_time = GetCurrentTimestamp();
1183 17442 : foreach(cell, dblist)
1184 : {
1185 13108 : avw_dbase *tmp = lfirst(cell);
1186 : dlist_iter iter;
1187 :
1188 : /* Check to see if this one is at risk of wraparound */
1189 13108 : if (TransactionIdPrecedes(tmp->adw_frozenxid, xidForceLimit))
1190 : {
1191 9916 : if (avdb == NULL ||
1192 3902 : TransactionIdPrecedes(tmp->adw_frozenxid,
1193 : avdb->adw_frozenxid))
1194 2210 : avdb = tmp;
1195 6014 : for_xid_wrap = true;
1196 10390 : continue;
1197 : }
1198 7094 : else if (for_xid_wrap)
1199 210 : continue; /* ignore not-at-risk DBs */
1200 6884 : else if (MultiXactIdPrecedes(tmp->adw_minmulti, multiForceLimit))
1201 : {
1202 0 : if (avdb == NULL ||
1203 0 : MultiXactIdPrecedes(tmp->adw_minmulti, avdb->adw_minmulti))
1204 0 : avdb = tmp;
1205 0 : for_multi_wrap = true;
1206 0 : continue;
1207 : }
1208 6884 : else if (for_multi_wrap)
1209 0 : continue; /* ignore not-at-risk DBs */
1210 :
1211 : /* Find pgstat entry if any */
1212 6884 : tmp->adw_entry = pgstat_fetch_stat_dbentry(tmp->adw_datid);
1213 :
1214 : /*
1215 : * Skip a database with no pgstat entry; it means it hasn't seen any
1216 : * activity.
1217 : */
1218 6884 : if (!tmp->adw_entry)
1219 178 : continue;
1220 :
1221 : /*
1222 : * Also, skip a database that appears on the database list as having
1223 : * been processed recently (less than autovacuum_naptime seconds ago).
1224 : * We do this so that we don't select a database which we just
1225 : * selected, but that pgstat hasn't gotten around to updating the last
1226 : * autovacuum time yet.
1227 : */
1228 6706 : skipit = false;
1229 :
1230 13546 : dlist_reverse_foreach(iter, &DatabaseList)
1231 : {
1232 13496 : avl_dbase *dbp = dlist_container(avl_dbase, adl_node, iter.cur);
1233 :
1234 13496 : if (dbp->adl_datid == tmp->adw_datid)
1235 : {
1236 : /*
1237 : * Skip this database if its next_worker value falls between
1238 : * the current time and the current time plus naptime.
1239 : */
1240 6656 : if (!TimestampDifferenceExceeds(dbp->adl_next_worker,
1241 3988 : current_time, 0) &&
1242 3988 : !TimestampDifferenceExceeds(current_time,
1243 : dbp->adl_next_worker,
1244 : autovacuum_naptime * 1000))
1245 3988 : skipit = true;
1246 :
1247 6656 : break;
1248 : }
1249 : }
1250 6706 : if (skipit)
1251 3988 : continue;
1252 :
1253 : /*
1254 : * Remember the db with oldest autovac time. (If we are here, both
1255 : * tmp->entry and db->entry must be non-null.)
1256 : */
1257 2718 : if (avdb == NULL ||
1258 508 : tmp->adw_entry->last_autovac_time < avdb->adw_entry->last_autovac_time)
1259 2380 : avdb = tmp;
1260 : }
1261 :
1262 : /* Found a database -- process it */
1263 4334 : if (avdb != NULL)
1264 : {
1265 : WorkerInfo worker;
1266 : dlist_node *wptr;
1267 :
1268 4322 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
1269 :
1270 : /*
1271 : * Get a worker entry from the freelist. We checked above, so there
1272 : * really should be a free slot.
1273 : */
1274 4322 : wptr = dclist_pop_head_node(&AutoVacuumShmem->av_freeWorkers);
1275 :
1276 4322 : worker = dlist_container(WorkerInfoData, wi_links, wptr);
1277 4322 : worker->wi_dboid = avdb->adw_datid;
1278 4322 : worker->wi_proc = NULL;
1279 4322 : worker->wi_launchtime = GetCurrentTimestamp();
1280 :
1281 4322 : AutoVacuumShmem->av_startingWorker = worker;
1282 :
1283 4322 : LWLockRelease(AutovacuumLock);
1284 :
1285 4322 : SendPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER);
1286 :
1287 4322 : retval = avdb->adw_datid;
1288 : }
1289 12 : else if (skipit)
1290 : {
1291 : /*
1292 : * If we skipped all databases on the list, rebuild it, because it
1293 : * probably contains a dropped database.
1294 : */
1295 0 : rebuild_database_list(InvalidOid);
1296 : }
1297 :
1298 4334 : MemoryContextSwitchTo(oldcxt);
1299 4334 : MemoryContextDelete(tmpcxt);
1300 :
1301 4334 : return retval;
1302 : }
1303 :
1304 : /*
1305 : * launch_worker
1306 : *
1307 : * Wrapper for starting a worker from the launcher. Besides actually starting
1308 : * it, update the database list to reflect the next time that another one will
1309 : * need to be started on the selected database. The actual database choice is
1310 : * left to do_start_worker.
1311 : *
1312 : * This routine is also expected to insert an entry into the database list if
1313 : * the selected database was previously absent from the list.
1314 : */
1315 : static void
1316 4334 : launch_worker(TimestampTz now)
1317 : {
1318 : Oid dbid;
1319 : dlist_iter iter;
1320 :
1321 4334 : dbid = do_start_worker();
1322 4334 : if (OidIsValid(dbid))
1323 : {
1324 4322 : bool found = false;
1325 :
1326 : /*
1327 : * Walk the database list and update the corresponding entry. If the
1328 : * database is not on the list, we'll recreate the list.
1329 : */
1330 9502 : dlist_foreach(iter, &DatabaseList)
1331 : {
1332 9472 : avl_dbase *avdb = dlist_container(avl_dbase, adl_node, iter.cur);
1333 :
1334 9472 : if (avdb->adl_datid == dbid)
1335 : {
1336 4292 : found = true;
1337 :
1338 : /*
1339 : * add autovacuum_naptime seconds to the current time, and use
1340 : * that as the new "next_worker" field for this database.
1341 : */
1342 4292 : avdb->adl_next_worker =
1343 4292 : TimestampTzPlusMilliseconds(now, autovacuum_naptime * 1000);
1344 :
1345 4292 : dlist_move_head(&DatabaseList, iter.cur);
1346 4292 : break;
1347 : }
1348 : }
1349 :
1350 : /*
1351 : * If the database was not present in the database list, we rebuild
1352 : * the list. It's possible that the database does not get into the
1353 : * list anyway, for example if it's a database that doesn't have a
1354 : * pgstat entry, but this is not a problem because we don't want to
1355 : * schedule workers regularly into those in any case.
1356 : */
1357 4322 : if (!found)
1358 30 : rebuild_database_list(dbid);
1359 : }
1360 4334 : }
1361 :
1362 : /*
1363 : * Called from postmaster to signal a failure to fork a process to become
1364 : * worker. The postmaster should kill(SIGUSR2) the launcher shortly
1365 : * after calling this function.
1366 : */
1367 : void
1368 0 : AutoVacWorkerFailed(void)
1369 : {
1370 0 : AutoVacuumShmem->av_signal[AutoVacForkFailed] = true;
1371 0 : }
1372 :
1373 : /* SIGUSR2: a worker is up and running, or just finished, or failed to fork */
1374 : static void
1375 8636 : avl_sigusr2_handler(SIGNAL_ARGS)
1376 : {
1377 8636 : got_SIGUSR2 = true;
1378 8636 : SetLatch(MyLatch);
1379 8636 : }
1380 :
1381 :
1382 : /********************************************************************
1383 : * AUTOVACUUM WORKER CODE
1384 : ********************************************************************/
1385 :
1386 : /*
1387 : * Main entry point for autovacuum worker processes.
1388 : */
1389 : void
1390 4324 : AutoVacWorkerMain(const void *startup_data, size_t startup_data_len)
1391 : {
1392 : sigjmp_buf local_sigjmp_buf;
1393 : Oid dbid;
1394 :
1395 : Assert(startup_data_len == 0);
1396 :
1397 : /* Release postmaster's working memory context */
1398 4324 : if (PostmasterContext)
1399 : {
1400 4324 : MemoryContextDelete(PostmasterContext);
1401 4324 : PostmasterContext = NULL;
1402 : }
1403 :
1404 4324 : MyBackendType = B_AUTOVAC_WORKER;
1405 4324 : init_ps_display(NULL);
1406 :
1407 : Assert(GetProcessingMode() == InitProcessing);
1408 :
1409 : /*
1410 : * Set up signal handlers. We operate on databases much like a regular
1411 : * backend, so we use the same signal handling. See equivalent code in
1412 : * tcop/postgres.c.
1413 : */
1414 4324 : pqsignal(SIGHUP, SignalHandlerForConfigReload);
1415 :
1416 : /*
1417 : * SIGINT is used to signal canceling the current table's vacuum; SIGTERM
1418 : * means abort and exit cleanly, and SIGQUIT means abandon ship.
1419 : */
1420 4324 : pqsignal(SIGINT, StatementCancelHandler);
1421 4324 : pqsignal(SIGTERM, die);
1422 : /* SIGQUIT handler was already set up by InitPostmasterChild */
1423 :
1424 4324 : InitializeTimeouts(); /* establishes SIGALRM handler */
1425 :
1426 4324 : pqsignal(SIGPIPE, SIG_IGN);
1427 4324 : pqsignal(SIGUSR1, procsignal_sigusr1_handler);
1428 4324 : pqsignal(SIGUSR2, SIG_IGN);
1429 4324 : pqsignal(SIGFPE, FloatExceptionHandler);
1430 4324 : pqsignal(SIGCHLD, SIG_DFL);
1431 :
1432 : /*
1433 : * Create a per-backend PGPROC struct in shared memory. We must do this
1434 : * before we can use LWLocks or access any shared memory.
1435 : */
1436 4324 : InitProcess();
1437 :
1438 : /* Early initialization */
1439 4324 : BaseInit();
1440 :
1441 : /*
1442 : * If an exception is encountered, processing resumes here.
1443 : *
1444 : * Unlike most auxiliary processes, we don't attempt to continue
1445 : * processing after an error; we just clean up and exit. The autovac
1446 : * launcher is responsible for spawning another worker later.
1447 : *
1448 : * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
1449 : * (to wit, BlockSig) will be restored when longjmp'ing to here. Thus,
1450 : * signals other than SIGQUIT will be blocked until we exit. It might
1451 : * seem that this policy makes the HOLD_INTERRUPTS() call redundant, but
1452 : * it is not since InterruptPending might be set already.
1453 : */
1454 4324 : if (sigsetjmp(local_sigjmp_buf, 1) != 0)
1455 : {
1456 : /* since not using PG_TRY, must reset error stack by hand */
1457 0 : error_context_stack = NULL;
1458 :
1459 : /* Prevents interrupts while cleaning up */
1460 0 : HOLD_INTERRUPTS();
1461 :
1462 : /* Report the error to the server log */
1463 0 : EmitErrorReport();
1464 :
1465 : /*
1466 : * We can now go away. Note that because we called InitProcess, a
1467 : * callback was registered to do ProcKill, which will clean up
1468 : * necessary state.
1469 : */
1470 0 : proc_exit(0);
1471 : }
1472 :
1473 : /* We can now handle ereport(ERROR) */
1474 4324 : PG_exception_stack = &local_sigjmp_buf;
1475 :
1476 4324 : sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
1477 :
1478 : /*
1479 : * Set always-secure search path, so malicious users can't redirect user
1480 : * code (e.g. pg_index.indexprs). (That code runs in a
1481 : * SECURITY_RESTRICTED_OPERATION sandbox, so malicious users could not
1482 : * take control of the entire autovacuum worker in any case.)
1483 : */
1484 4324 : SetConfigOption("search_path", "", PGC_SUSET, PGC_S_OVERRIDE);
1485 :
1486 : /*
1487 : * Force zero_damaged_pages OFF in the autovac process, even if it is set
1488 : * in postgresql.conf. We don't really want such a dangerous option being
1489 : * applied non-interactively.
1490 : */
1491 4324 : SetConfigOption("zero_damaged_pages", "false", PGC_SUSET, PGC_S_OVERRIDE);
1492 :
1493 : /*
1494 : * Force settable timeouts off to avoid letting these settings prevent
1495 : * regular maintenance from being executed.
1496 : */
1497 4324 : SetConfigOption("statement_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
1498 4324 : SetConfigOption("transaction_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
1499 4324 : SetConfigOption("lock_timeout", "0", PGC_SUSET, PGC_S_OVERRIDE);
1500 4324 : SetConfigOption("idle_in_transaction_session_timeout", "0",
1501 : PGC_SUSET, PGC_S_OVERRIDE);
1502 :
1503 : /*
1504 : * Force default_transaction_isolation to READ COMMITTED. We don't want
1505 : * to pay the overhead of serializable mode, nor add any risk of causing
1506 : * deadlocks or delaying other transactions.
1507 : */
1508 4324 : SetConfigOption("default_transaction_isolation", "read committed",
1509 : PGC_SUSET, PGC_S_OVERRIDE);
1510 :
1511 : /*
1512 : * Force synchronous replication off to allow regular maintenance even if
1513 : * we are waiting for standbys to connect. This is important to ensure we
1514 : * aren't blocked from performing anti-wraparound tasks.
1515 : */
1516 4324 : if (synchronous_commit > SYNCHRONOUS_COMMIT_LOCAL_FLUSH)
1517 4324 : SetConfigOption("synchronous_commit", "local",
1518 : PGC_SUSET, PGC_S_OVERRIDE);
1519 :
1520 : /*
1521 : * Even when system is configured to use a different fetch consistency,
1522 : * for autovac we always want fresh stats.
1523 : */
1524 4324 : SetConfigOption("stats_fetch_consistency", "none", PGC_SUSET, PGC_S_OVERRIDE);
1525 :
1526 : /*
1527 : * Get the info about the database we're going to work on.
1528 : */
1529 4324 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
1530 :
1531 : /*
1532 : * beware of startingWorker being INVALID; this should normally not
1533 : * happen, but if a worker fails after forking and before this, the
1534 : * launcher might have decided to remove it from the queue and start
1535 : * again.
1536 : */
1537 4324 : if (AutoVacuumShmem->av_startingWorker != NULL)
1538 : {
1539 4324 : MyWorkerInfo = AutoVacuumShmem->av_startingWorker;
1540 4324 : dbid = MyWorkerInfo->wi_dboid;
1541 4324 : MyWorkerInfo->wi_proc = MyProc;
1542 :
1543 : /* insert into the running list */
1544 4324 : dlist_push_head(&AutoVacuumShmem->av_runningWorkers,
1545 4324 : &MyWorkerInfo->wi_links);
1546 :
1547 : /*
1548 : * remove from the "starting" pointer, so that the launcher can start
1549 : * a new worker if required
1550 : */
1551 4324 : AutoVacuumShmem->av_startingWorker = NULL;
1552 4324 : LWLockRelease(AutovacuumLock);
1553 :
1554 4324 : on_shmem_exit(FreeWorkerInfo, 0);
1555 :
1556 : /* wake up the launcher */
1557 4324 : if (AutoVacuumShmem->av_launcherpid != 0)
1558 4324 : kill(AutoVacuumShmem->av_launcherpid, SIGUSR2);
1559 : }
1560 : else
1561 : {
1562 : /* no worker entry for me, go away */
1563 0 : elog(WARNING, "autovacuum worker started without a worker entry");
1564 0 : dbid = InvalidOid;
1565 0 : LWLockRelease(AutovacuumLock);
1566 : }
1567 :
1568 4324 : if (OidIsValid(dbid))
1569 : {
1570 : char dbname[NAMEDATALEN];
1571 :
1572 : /*
1573 : * Report autovac startup to the cumulative stats system. We
1574 : * deliberately do this before InitPostgres, so that the
1575 : * last_autovac_time will get updated even if the connection attempt
1576 : * fails. This is to prevent autovac from getting "stuck" repeatedly
1577 : * selecting an unopenable database, rather than making any progress
1578 : * on stuff it can connect to.
1579 : */
1580 4324 : pgstat_report_autovac(dbid);
1581 :
1582 : /*
1583 : * Connect to the selected database, specifying no particular user,
1584 : * and ignoring datallowconn. Collect the database's name for
1585 : * display.
1586 : *
1587 : * Note: if we have selected a just-deleted database (due to using
1588 : * stale stats info), we'll fail and exit here.
1589 : */
1590 4324 : InitPostgres(NULL, dbid, NULL, InvalidOid,
1591 : INIT_PG_OVERRIDE_ALLOW_CONNS,
1592 : dbname);
1593 4324 : SetProcessingMode(NormalProcessing);
1594 4324 : set_ps_display(dbname);
1595 4324 : ereport(DEBUG1,
1596 : (errmsg_internal("autovacuum: processing database \"%s\"", dbname)));
1597 :
1598 4324 : if (PostAuthDelay)
1599 0 : pg_usleep(PostAuthDelay * 1000000L);
1600 :
1601 : /* And do an appropriate amount of work */
1602 4324 : recentXid = ReadNextTransactionId();
1603 4324 : recentMulti = ReadNextMultiXactId();
1604 4324 : do_autovacuum();
1605 : }
1606 :
1607 : /*
1608 : * The launcher will be notified of my death in ProcKill, *if* we managed
1609 : * to get a worker slot at all
1610 : */
1611 :
1612 : /* All done, go away */
1613 4318 : proc_exit(0);
1614 : }
1615 :
1616 : /*
1617 : * Return a WorkerInfo to the free list
1618 : */
1619 : static void
1620 4324 : FreeWorkerInfo(int code, Datum arg)
1621 : {
1622 4324 : if (MyWorkerInfo != NULL)
1623 : {
1624 4324 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
1625 :
1626 : /*
1627 : * Wake the launcher up so that he can launch a new worker immediately
1628 : * if required. We only save the launcher's PID in local memory here;
1629 : * the actual signal will be sent when the PGPROC is recycled. Note
1630 : * that we always do this, so that the launcher can rebalance the cost
1631 : * limit setting of the remaining workers.
1632 : *
1633 : * We somewhat ignore the risk that the launcher changes its PID
1634 : * between us reading it and the actual kill; we expect ProcKill to be
1635 : * called shortly after us, and we assume that PIDs are not reused too
1636 : * quickly after a process exits.
1637 : */
1638 4324 : AutovacuumLauncherPid = AutoVacuumShmem->av_launcherpid;
1639 :
1640 4324 : dlist_delete(&MyWorkerInfo->wi_links);
1641 4324 : MyWorkerInfo->wi_dboid = InvalidOid;
1642 4324 : MyWorkerInfo->wi_tableoid = InvalidOid;
1643 4324 : MyWorkerInfo->wi_sharedrel = false;
1644 4324 : MyWorkerInfo->wi_proc = NULL;
1645 4324 : MyWorkerInfo->wi_launchtime = 0;
1646 4324 : pg_atomic_clear_flag(&MyWorkerInfo->wi_dobalance);
1647 4324 : dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
1648 4324 : &MyWorkerInfo->wi_links);
1649 : /* not mine anymore */
1650 4324 : MyWorkerInfo = NULL;
1651 :
1652 : /*
1653 : * now that we're inactive, cause a rebalancing of the surviving
1654 : * workers
1655 : */
1656 4324 : AutoVacuumShmem->av_signal[AutoVacRebalance] = true;
1657 4324 : LWLockRelease(AutovacuumLock);
1658 : }
1659 4324 : }
1660 :
1661 : /*
1662 : * Update vacuum cost-based delay-related parameters for autovacuum workers and
1663 : * backends executing VACUUM or ANALYZE using the value of relevant GUCs and
1664 : * global state. This must be called during setup for vacuum and after every
1665 : * config reload to ensure up-to-date values.
1666 : */
1667 : void
1668 471276 : VacuumUpdateCosts(void)
1669 : {
1670 471276 : if (MyWorkerInfo)
1671 : {
1672 457564 : if (av_storage_param_cost_delay >= 0)
1673 0 : vacuum_cost_delay = av_storage_param_cost_delay;
1674 457564 : else if (autovacuum_vac_cost_delay >= 0)
1675 457564 : vacuum_cost_delay = autovacuum_vac_cost_delay;
1676 : else
1677 : /* fall back to VacuumCostDelay */
1678 0 : vacuum_cost_delay = VacuumCostDelay;
1679 :
1680 457564 : AutoVacuumUpdateCostLimit();
1681 : }
1682 : else
1683 : {
1684 : /* Must be explicit VACUUM or ANALYZE */
1685 13712 : vacuum_cost_delay = VacuumCostDelay;
1686 13712 : vacuum_cost_limit = VacuumCostLimit;
1687 : }
1688 :
1689 : /*
1690 : * If configuration changes are allowed to impact VacuumCostActive, make
1691 : * sure it is updated.
1692 : */
1693 471276 : if (VacuumFailsafeActive)
1694 : Assert(!VacuumCostActive);
1695 471276 : else if (vacuum_cost_delay > 0)
1696 457564 : VacuumCostActive = true;
1697 : else
1698 : {
1699 13712 : VacuumCostActive = false;
1700 13712 : VacuumCostBalance = 0;
1701 : }
1702 :
1703 : /*
1704 : * Since the cost logging requires a lock, avoid rendering the log message
1705 : * in case we are using a message level where the log wouldn't be emitted.
1706 : */
1707 471276 : if (MyWorkerInfo && message_level_is_interesting(DEBUG2))
1708 : {
1709 : Oid dboid,
1710 : tableoid;
1711 :
1712 : Assert(!LWLockHeldByMe(AutovacuumLock));
1713 :
1714 0 : LWLockAcquire(AutovacuumLock, LW_SHARED);
1715 0 : dboid = MyWorkerInfo->wi_dboid;
1716 0 : tableoid = MyWorkerInfo->wi_tableoid;
1717 0 : LWLockRelease(AutovacuumLock);
1718 :
1719 0 : elog(DEBUG2,
1720 : "Autovacuum VacuumUpdateCosts(db=%u, rel=%u, dobalance=%s, cost_limit=%d, cost_delay=%g active=%s failsafe=%s)",
1721 : dboid, tableoid, pg_atomic_unlocked_test_flag(&MyWorkerInfo->wi_dobalance) ? "no" : "yes",
1722 : vacuum_cost_limit, vacuum_cost_delay,
1723 : vacuum_cost_delay > 0 ? "yes" : "no",
1724 : VacuumFailsafeActive ? "yes" : "no");
1725 : }
1726 471276 : }
1727 :
1728 : /*
1729 : * Update vacuum_cost_limit with the correct value for an autovacuum worker,
1730 : * given the value of other relevant cost limit parameters and the number of
1731 : * workers across which the limit must be balanced. Autovacuum workers must
1732 : * call this regularly in case av_nworkersForBalance has been updated by
1733 : * another worker or by the autovacuum launcher. They must also call it after a
1734 : * config reload.
1735 : */
1736 : void
1737 465818 : AutoVacuumUpdateCostLimit(void)
1738 : {
1739 465818 : if (!MyWorkerInfo)
1740 0 : return;
1741 :
1742 : /*
1743 : * note: in cost_limit, zero also means use value from elsewhere, because
1744 : * zero is not a valid value.
1745 : */
1746 :
1747 465818 : if (av_storage_param_cost_limit > 0)
1748 0 : vacuum_cost_limit = av_storage_param_cost_limit;
1749 : else
1750 : {
1751 : int nworkers_for_balance;
1752 :
1753 465818 : if (autovacuum_vac_cost_limit > 0)
1754 0 : vacuum_cost_limit = autovacuum_vac_cost_limit;
1755 : else
1756 465818 : vacuum_cost_limit = VacuumCostLimit;
1757 :
1758 : /* Only balance limit if no cost-related storage parameters specified */
1759 465818 : if (pg_atomic_unlocked_test_flag(&MyWorkerInfo->wi_dobalance))
1760 0 : return;
1761 :
1762 : Assert(vacuum_cost_limit > 0);
1763 :
1764 465818 : nworkers_for_balance = pg_atomic_read_u32(&AutoVacuumShmem->av_nworkersForBalance);
1765 :
1766 : /* There is at least 1 autovac worker (this worker) */
1767 465818 : if (nworkers_for_balance <= 0)
1768 0 : elog(ERROR, "nworkers_for_balance must be > 0");
1769 :
1770 465818 : vacuum_cost_limit = Max(vacuum_cost_limit / nworkers_for_balance, 1);
1771 : }
1772 : }
1773 :
1774 : /*
1775 : * autovac_recalculate_workers_for_balance
1776 : * Recalculate the number of workers to consider, given cost-related
1777 : * storage parameters and the current number of active workers.
1778 : *
1779 : * Caller must hold the AutovacuumLock in at least shared mode to access
1780 : * worker->wi_proc.
1781 : */
1782 : static void
1783 233096 : autovac_recalculate_workers_for_balance(void)
1784 : {
1785 : dlist_iter iter;
1786 : int orig_nworkers_for_balance;
1787 233096 : int nworkers_for_balance = 0;
1788 :
1789 : Assert(LWLockHeldByMe(AutovacuumLock));
1790 :
1791 233096 : orig_nworkers_for_balance =
1792 233096 : pg_atomic_read_u32(&AutoVacuumShmem->av_nworkersForBalance);
1793 :
1794 727530 : dlist_foreach(iter, &AutoVacuumShmem->av_runningWorkers)
1795 : {
1796 494434 : WorkerInfo worker = dlist_container(WorkerInfoData, wi_links, iter.cur);
1797 :
1798 988868 : if (worker->wi_proc == NULL ||
1799 494434 : pg_atomic_unlocked_test_flag(&worker->wi_dobalance))
1800 10272 : continue;
1801 :
1802 484162 : nworkers_for_balance++;
1803 : }
1804 :
1805 233096 : if (nworkers_for_balance != orig_nworkers_for_balance)
1806 4518 : pg_atomic_write_u32(&AutoVacuumShmem->av_nworkersForBalance,
1807 : nworkers_for_balance);
1808 233096 : }
1809 :
1810 : /*
1811 : * get_database_list
1812 : * Return a list of all databases found in pg_database.
1813 : *
1814 : * The list and associated data is allocated in the caller's memory context,
1815 : * which is in charge of ensuring that it's properly cleaned up afterwards.
1816 : *
1817 : * Note: this is the only function in which the autovacuum launcher uses a
1818 : * transaction. Although we aren't attached to any particular database and
1819 : * therefore can't access most catalogs, we do have enough infrastructure
1820 : * to do a seqscan on pg_database.
1821 : */
1822 : static List *
1823 5418 : get_database_list(void)
1824 : {
1825 5418 : List *dblist = NIL;
1826 : Relation rel;
1827 : TableScanDesc scan;
1828 : HeapTuple tup;
1829 : MemoryContext resultcxt;
1830 :
1831 : /* This is the context that we will allocate our output data in */
1832 5418 : resultcxt = CurrentMemoryContext;
1833 :
1834 : /*
1835 : * Start a transaction so we can access pg_database.
1836 : */
1837 5418 : StartTransactionCommand();
1838 :
1839 5418 : rel = table_open(DatabaseRelationId, AccessShareLock);
1840 5418 : scan = table_beginscan_catalog(rel, 0, NULL);
1841 :
1842 22102 : while (HeapTupleIsValid(tup = heap_getnext(scan, ForwardScanDirection)))
1843 : {
1844 16684 : Form_pg_database pgdatabase = (Form_pg_database) GETSTRUCT(tup);
1845 : avw_dbase *avdb;
1846 : MemoryContext oldcxt;
1847 :
1848 : /*
1849 : * If database has partially been dropped, we can't, nor need to,
1850 : * vacuum it.
1851 : */
1852 16684 : if (database_is_invalid_form(pgdatabase))
1853 : {
1854 4 : elog(DEBUG2,
1855 : "autovacuum: skipping invalid database \"%s\"",
1856 : NameStr(pgdatabase->datname));
1857 4 : continue;
1858 : }
1859 :
1860 : /*
1861 : * Allocate our results in the caller's context, not the
1862 : * transaction's. We do this inside the loop, and restore the original
1863 : * context at the end, so that leaky things like heap_getnext() are
1864 : * not called in a potentially long-lived context.
1865 : */
1866 16680 : oldcxt = MemoryContextSwitchTo(resultcxt);
1867 :
1868 16680 : avdb = (avw_dbase *) palloc(sizeof(avw_dbase));
1869 :
1870 16680 : avdb->adw_datid = pgdatabase->oid;
1871 16680 : avdb->adw_name = pstrdup(NameStr(pgdatabase->datname));
1872 16680 : avdb->adw_frozenxid = pgdatabase->datfrozenxid;
1873 16680 : avdb->adw_minmulti = pgdatabase->datminmxid;
1874 : /* this gets set later: */
1875 16680 : avdb->adw_entry = NULL;
1876 :
1877 16680 : dblist = lappend(dblist, avdb);
1878 16680 : MemoryContextSwitchTo(oldcxt);
1879 : }
1880 :
1881 5418 : table_endscan(scan);
1882 5418 : table_close(rel, AccessShareLock);
1883 :
1884 5418 : CommitTransactionCommand();
1885 :
1886 : /* Be sure to restore caller's memory context */
1887 5418 : MemoryContextSwitchTo(resultcxt);
1888 :
1889 5418 : return dblist;
1890 : }
1891 :
1892 : /*
1893 : * Process a database table-by-table
1894 : *
1895 : * Note that CHECK_FOR_INTERRUPTS is supposed to be used in certain spots in
1896 : * order not to ignore shutdown commands for too long.
1897 : */
1898 : static void
1899 4324 : do_autovacuum(void)
1900 : {
1901 : Relation classRel;
1902 : HeapTuple tuple;
1903 : TableScanDesc relScan;
1904 : Form_pg_database dbForm;
1905 4324 : List *table_oids = NIL;
1906 4324 : List *orphan_oids = NIL;
1907 : HASHCTL ctl;
1908 : HTAB *table_toast_map;
1909 : ListCell *volatile cell;
1910 : BufferAccessStrategy bstrategy;
1911 : ScanKeyData key;
1912 : TupleDesc pg_class_desc;
1913 : int effective_multixact_freeze_max_age;
1914 4324 : bool did_vacuum = false;
1915 4324 : bool found_concurrent_worker = false;
1916 : int i;
1917 :
1918 : /*
1919 : * StartTransactionCommand and CommitTransactionCommand will automatically
1920 : * switch to other contexts. We need this one to keep the list of
1921 : * relations to vacuum/analyze across transactions.
1922 : */
1923 4324 : AutovacMemCxt = AllocSetContextCreate(TopMemoryContext,
1924 : "Autovacuum worker",
1925 : ALLOCSET_DEFAULT_SIZES);
1926 4324 : MemoryContextSwitchTo(AutovacMemCxt);
1927 :
1928 : /* Start a transaction so our commands have one to play into. */
1929 4324 : StartTransactionCommand();
1930 :
1931 : /*
1932 : * This injection point is put in a transaction block to work with a wait
1933 : * that uses a condition variable.
1934 : */
1935 4324 : INJECTION_POINT("autovacuum-worker-start", NULL);
1936 :
1937 : /*
1938 : * Compute the multixact age for which freezing is urgent. This is
1939 : * normally autovacuum_multixact_freeze_max_age, but may be less if we are
1940 : * short of multixact member space.
1941 : */
1942 4322 : effective_multixact_freeze_max_age = MultiXactMemberFreezeThreshold();
1943 :
1944 : /*
1945 : * Find the pg_database entry and select the default freeze ages. We use
1946 : * zero in template and nonconnectable databases, else the system-wide
1947 : * default.
1948 : */
1949 4322 : tuple = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
1950 4322 : if (!HeapTupleIsValid(tuple))
1951 0 : elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
1952 4322 : dbForm = (Form_pg_database) GETSTRUCT(tuple);
1953 :
1954 4322 : if (dbForm->datistemplate || !dbForm->datallowconn)
1955 : {
1956 1654 : default_freeze_min_age = 0;
1957 1654 : default_freeze_table_age = 0;
1958 1654 : default_multixact_freeze_min_age = 0;
1959 1654 : default_multixact_freeze_table_age = 0;
1960 : }
1961 : else
1962 : {
1963 2668 : default_freeze_min_age = vacuum_freeze_min_age;
1964 2668 : default_freeze_table_age = vacuum_freeze_table_age;
1965 2668 : default_multixact_freeze_min_age = vacuum_multixact_freeze_min_age;
1966 2668 : default_multixact_freeze_table_age = vacuum_multixact_freeze_table_age;
1967 : }
1968 :
1969 4322 : ReleaseSysCache(tuple);
1970 :
1971 : /* StartTransactionCommand changed elsewhere */
1972 4322 : MemoryContextSwitchTo(AutovacMemCxt);
1973 :
1974 4322 : classRel = table_open(RelationRelationId, AccessShareLock);
1975 :
1976 : /* create a copy so we can use it after closing pg_class */
1977 4322 : pg_class_desc = CreateTupleDescCopy(RelationGetDescr(classRel));
1978 :
1979 : /* create hash table for toast <-> main relid mapping */
1980 4322 : ctl.keysize = sizeof(Oid);
1981 4322 : ctl.entrysize = sizeof(av_relation);
1982 :
1983 4322 : table_toast_map = hash_create("TOAST to main relid map",
1984 : 100,
1985 : &ctl,
1986 : HASH_ELEM | HASH_BLOBS);
1987 :
1988 : /*
1989 : * Scan pg_class to determine which tables to vacuum.
1990 : *
1991 : * We do this in two passes: on the first one we collect the list of plain
1992 : * relations and materialized views, and on the second one we collect
1993 : * TOAST tables. The reason for doing the second pass is that during it we
1994 : * want to use the main relation's pg_class.reloptions entry if the TOAST
1995 : * table does not have any, and we cannot obtain it unless we know
1996 : * beforehand what's the main table OID.
1997 : *
1998 : * We need to check TOAST tables separately because in cases with short,
1999 : * wide tables there might be proportionally much more activity in the
2000 : * TOAST table than in its parent.
2001 : */
2002 4322 : relScan = table_beginscan_catalog(classRel, 0, NULL);
2003 :
2004 : /*
2005 : * On the first pass, we collect main tables to vacuum, and also the main
2006 : * table relid to TOAST relid mapping.
2007 : */
2008 1830606 : while ((tuple = heap_getnext(relScan, ForwardScanDirection)) != NULL)
2009 : {
2010 1826284 : Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
2011 : PgStat_StatTabEntry *tabentry;
2012 : AutoVacOpts *relopts;
2013 : Oid relid;
2014 : bool dovacuum;
2015 : bool doanalyze;
2016 : bool wraparound;
2017 :
2018 1826284 : if (classForm->relkind != RELKIND_RELATION &&
2019 1524722 : classForm->relkind != RELKIND_MATVIEW)
2020 1524658 : continue;
2021 :
2022 301642 : relid = classForm->oid;
2023 :
2024 : /*
2025 : * Check if it is a temp table (presumably, of some other backend's).
2026 : * We cannot safely process other backends' temp tables.
2027 : */
2028 301642 : if (classForm->relpersistence == RELPERSISTENCE_TEMP)
2029 : {
2030 : /*
2031 : * We just ignore it if the owning backend is still active and
2032 : * using the temporary schema. Also, for safety, ignore it if the
2033 : * namespace doesn't exist or isn't a temp namespace after all.
2034 : */
2035 16 : if (checkTempNamespaceStatus(classForm->relnamespace) == TEMP_NAMESPACE_IDLE)
2036 : {
2037 : /*
2038 : * The table seems to be orphaned -- although it might be that
2039 : * the owning backend has already deleted it and exited; our
2040 : * pg_class scan snapshot is not necessarily up-to-date
2041 : * anymore, so we could be looking at a committed-dead entry.
2042 : * Remember it so we can try to delete it later.
2043 : */
2044 0 : orphan_oids = lappend_oid(orphan_oids, relid);
2045 : }
2046 16 : continue;
2047 : }
2048 :
2049 : /* Fetch reloptions and the pgstat entry for this table */
2050 301626 : relopts = extract_autovac_opts(tuple, pg_class_desc);
2051 301626 : tabentry = pgstat_fetch_stat_tabentry_ext(classForm->relisshared,
2052 : relid);
2053 :
2054 : /* Check if it needs vacuum or analyze */
2055 301626 : relation_needs_vacanalyze(relid, relopts, classForm, tabentry,
2056 : effective_multixact_freeze_max_age,
2057 : &dovacuum, &doanalyze, &wraparound);
2058 :
2059 : /* Relations that need work are added to table_oids */
2060 301626 : if (dovacuum || doanalyze)
2061 145856 : table_oids = lappend_oid(table_oids, relid);
2062 :
2063 : /*
2064 : * Remember TOAST associations for the second pass. Note: we must do
2065 : * this whether or not the table is going to be vacuumed, because we
2066 : * don't automatically vacuum toast tables along the parent table.
2067 : */
2068 301626 : if (OidIsValid(classForm->reltoastrelid))
2069 : {
2070 : av_relation *hentry;
2071 : bool found;
2072 :
2073 347572 : hentry = hash_search(table_toast_map,
2074 173786 : &classForm->reltoastrelid,
2075 : HASH_ENTER, &found);
2076 :
2077 173786 : if (!found)
2078 : {
2079 : /* hash_search already filled in the key */
2080 173786 : hentry->ar_relid = relid;
2081 173786 : hentry->ar_hasrelopts = false;
2082 173786 : if (relopts != NULL)
2083 : {
2084 3762 : hentry->ar_hasrelopts = true;
2085 3762 : memcpy(&hentry->ar_reloptions, relopts,
2086 : sizeof(AutoVacOpts));
2087 : }
2088 : }
2089 : }
2090 :
2091 : /* Release stuff to avoid per-relation leakage */
2092 301626 : if (relopts)
2093 3830 : pfree(relopts);
2094 301626 : if (tabentry)
2095 297258 : pfree(tabentry);
2096 : }
2097 :
2098 4322 : table_endscan(relScan);
2099 :
2100 : /* second pass: check TOAST tables */
2101 4322 : ScanKeyInit(&key,
2102 : Anum_pg_class_relkind,
2103 : BTEqualStrategyNumber, F_CHAREQ,
2104 : CharGetDatum(RELKIND_TOASTVALUE));
2105 :
2106 4322 : relScan = table_beginscan_catalog(classRel, 1, &key);
2107 178114 : while ((tuple = heap_getnext(relScan, ForwardScanDirection)) != NULL)
2108 : {
2109 173792 : Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
2110 : PgStat_StatTabEntry *tabentry;
2111 : Oid relid;
2112 : AutoVacOpts *relopts;
2113 173792 : bool free_relopts = false;
2114 : bool dovacuum;
2115 : bool doanalyze;
2116 : bool wraparound;
2117 :
2118 : /*
2119 : * We cannot safely process other backends' temp tables, so skip 'em.
2120 : */
2121 173792 : if (classForm->relpersistence == RELPERSISTENCE_TEMP)
2122 6 : continue;
2123 :
2124 173786 : relid = classForm->oid;
2125 :
2126 : /*
2127 : * fetch reloptions -- if this toast table does not have them, try the
2128 : * main rel
2129 : */
2130 173786 : relopts = extract_autovac_opts(tuple, pg_class_desc);
2131 173786 : if (relopts)
2132 2 : free_relopts = true;
2133 : else
2134 : {
2135 : av_relation *hentry;
2136 : bool found;
2137 :
2138 173784 : hentry = hash_search(table_toast_map, &relid, HASH_FIND, &found);
2139 173784 : if (found && hentry->ar_hasrelopts)
2140 3760 : relopts = &hentry->ar_reloptions;
2141 : }
2142 :
2143 : /* Fetch the pgstat entry for this table */
2144 173786 : tabentry = pgstat_fetch_stat_tabentry_ext(classForm->relisshared,
2145 : relid);
2146 :
2147 173786 : relation_needs_vacanalyze(relid, relopts, classForm, tabentry,
2148 : effective_multixact_freeze_max_age,
2149 : &dovacuum, &doanalyze, &wraparound);
2150 :
2151 : /* ignore analyze for toast tables */
2152 173786 : if (dovacuum)
2153 84414 : table_oids = lappend_oid(table_oids, relid);
2154 :
2155 : /* Release stuff to avoid leakage */
2156 173786 : if (free_relopts)
2157 2 : pfree(relopts);
2158 173786 : if (tabentry)
2159 170482 : pfree(tabentry);
2160 : }
2161 :
2162 4322 : table_endscan(relScan);
2163 4322 : table_close(classRel, AccessShareLock);
2164 :
2165 : /*
2166 : * Recheck orphan temporary tables, and if they still seem orphaned, drop
2167 : * them. We'll eat a transaction per dropped table, which might seem
2168 : * excessive, but we should only need to do anything as a result of a
2169 : * previous backend crash, so this should not happen often enough to
2170 : * justify "optimizing". Using separate transactions ensures that we
2171 : * don't bloat the lock table if there are many temp tables to be dropped,
2172 : * and it ensures that we don't lose work if a deletion attempt fails.
2173 : */
2174 4322 : foreach(cell, orphan_oids)
2175 : {
2176 0 : Oid relid = lfirst_oid(cell);
2177 : Form_pg_class classForm;
2178 : ObjectAddress object;
2179 :
2180 : /*
2181 : * Check for user-requested abort.
2182 : */
2183 0 : CHECK_FOR_INTERRUPTS();
2184 :
2185 : /*
2186 : * Try to lock the table. If we can't get the lock immediately,
2187 : * somebody else is using (or dropping) the table, so it's not our
2188 : * concern anymore. Having the lock prevents race conditions below.
2189 : */
2190 0 : if (!ConditionalLockRelationOid(relid, AccessExclusiveLock))
2191 0 : continue;
2192 :
2193 : /*
2194 : * Re-fetch the pg_class tuple and re-check whether it still seems to
2195 : * be an orphaned temp table. If it's not there or no longer the same
2196 : * relation, ignore it.
2197 : */
2198 0 : tuple = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
2199 0 : if (!HeapTupleIsValid(tuple))
2200 : {
2201 : /* be sure to drop useless lock so we don't bloat lock table */
2202 0 : UnlockRelationOid(relid, AccessExclusiveLock);
2203 0 : continue;
2204 : }
2205 0 : classForm = (Form_pg_class) GETSTRUCT(tuple);
2206 :
2207 : /*
2208 : * Make all the same tests made in the loop above. In event of OID
2209 : * counter wraparound, the pg_class entry we have now might be
2210 : * completely unrelated to the one we saw before.
2211 : */
2212 0 : if (!((classForm->relkind == RELKIND_RELATION ||
2213 0 : classForm->relkind == RELKIND_MATVIEW) &&
2214 0 : classForm->relpersistence == RELPERSISTENCE_TEMP))
2215 : {
2216 0 : UnlockRelationOid(relid, AccessExclusiveLock);
2217 0 : continue;
2218 : }
2219 :
2220 0 : if (checkTempNamespaceStatus(classForm->relnamespace) != TEMP_NAMESPACE_IDLE)
2221 : {
2222 0 : UnlockRelationOid(relid, AccessExclusiveLock);
2223 0 : continue;
2224 : }
2225 :
2226 : /*
2227 : * Try to lock the temp namespace, too. Even though we have lock on
2228 : * the table itself, there's a risk of deadlock against an incoming
2229 : * backend trying to clean out the temp namespace, in case this table
2230 : * has dependencies (such as sequences) that the backend's
2231 : * performDeletion call might visit in a different order. If we can
2232 : * get AccessShareLock on the namespace, that's sufficient to ensure
2233 : * we're not running concurrently with RemoveTempRelations. If we
2234 : * can't, back off and let RemoveTempRelations do its thing.
2235 : */
2236 0 : if (!ConditionalLockDatabaseObject(NamespaceRelationId,
2237 : classForm->relnamespace, 0,
2238 : AccessShareLock))
2239 : {
2240 0 : UnlockRelationOid(relid, AccessExclusiveLock);
2241 0 : continue;
2242 : }
2243 :
2244 : /* OK, let's delete it */
2245 0 : ereport(LOG,
2246 : (errmsg("autovacuum: dropping orphan temp table \"%s.%s.%s\"",
2247 : get_database_name(MyDatabaseId),
2248 : get_namespace_name(classForm->relnamespace),
2249 : NameStr(classForm->relname))));
2250 :
2251 : /*
2252 : * Deletion might involve TOAST table access, so ensure we have a
2253 : * valid snapshot.
2254 : */
2255 0 : PushActiveSnapshot(GetTransactionSnapshot());
2256 :
2257 0 : object.classId = RelationRelationId;
2258 0 : object.objectId = relid;
2259 0 : object.objectSubId = 0;
2260 0 : performDeletion(&object, DROP_CASCADE,
2261 : PERFORM_DELETION_INTERNAL |
2262 : PERFORM_DELETION_QUIETLY |
2263 : PERFORM_DELETION_SKIP_EXTENSIONS);
2264 :
2265 : /*
2266 : * To commit the deletion, end current transaction and start a new
2267 : * one. Note this also releases the locks we took.
2268 : */
2269 0 : PopActiveSnapshot();
2270 0 : CommitTransactionCommand();
2271 0 : StartTransactionCommand();
2272 :
2273 : /* StartTransactionCommand changed current memory context */
2274 0 : MemoryContextSwitchTo(AutovacMemCxt);
2275 : }
2276 :
2277 : /*
2278 : * Optionally, create a buffer access strategy object for VACUUM to use.
2279 : * We use the same BufferAccessStrategy object for all tables VACUUMed by
2280 : * this worker to prevent autovacuum from blowing out shared buffers.
2281 : *
2282 : * VacuumBufferUsageLimit being set to 0 results in
2283 : * GetAccessStrategyWithSize returning NULL, effectively meaning we can
2284 : * use up to all of shared buffers.
2285 : *
2286 : * If we later enter failsafe mode on any of the tables being vacuumed, we
2287 : * will cease use of the BufferAccessStrategy only for that table.
2288 : *
2289 : * XXX should we consider adding code to adjust the size of this if
2290 : * VacuumBufferUsageLimit changes?
2291 : */
2292 4322 : bstrategy = GetAccessStrategyWithSize(BAS_VACUUM, VacuumBufferUsageLimit);
2293 :
2294 : /*
2295 : * create a memory context to act as fake PortalContext, so that the
2296 : * contexts created in the vacuum code are cleaned up for each table.
2297 : */
2298 4322 : PortalContext = AllocSetContextCreate(AutovacMemCxt,
2299 : "Autovacuum Portal",
2300 : ALLOCSET_DEFAULT_SIZES);
2301 :
2302 : /*
2303 : * Perform operations on collected tables.
2304 : */
2305 234462 : foreach(cell, table_oids)
2306 : {
2307 230144 : Oid relid = lfirst_oid(cell);
2308 : HeapTuple classTup;
2309 : autovac_table *tab;
2310 : bool isshared;
2311 : bool skipit;
2312 : dlist_iter iter;
2313 :
2314 230144 : CHECK_FOR_INTERRUPTS();
2315 :
2316 : /*
2317 : * Check for config changes before processing each collected table.
2318 : */
2319 230144 : if (ConfigReloadPending)
2320 : {
2321 0 : ConfigReloadPending = false;
2322 0 : ProcessConfigFile(PGC_SIGHUP);
2323 :
2324 : /*
2325 : * You might be tempted to bail out if we see autovacuum is now
2326 : * disabled. Must resist that temptation -- this might be a
2327 : * for-wraparound emergency worker, in which case that would be
2328 : * entirely inappropriate.
2329 : */
2330 : }
2331 :
2332 : /*
2333 : * Find out whether the table is shared or not. (It's slightly
2334 : * annoying to fetch the syscache entry just for this, but in typical
2335 : * cases it adds little cost because table_recheck_autovac would
2336 : * refetch the entry anyway. We could buy that back by copying the
2337 : * tuple here and passing it to table_recheck_autovac, but that
2338 : * increases the odds of that function working with stale data.)
2339 : */
2340 230144 : classTup = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
2341 230144 : if (!HeapTupleIsValid(classTup))
2342 1362 : continue; /* somebody deleted the rel, forget it */
2343 230144 : isshared = ((Form_pg_class) GETSTRUCT(classTup))->relisshared;
2344 230144 : ReleaseSysCache(classTup);
2345 :
2346 : /*
2347 : * Hold schedule lock from here until we've claimed the table. We
2348 : * also need the AutovacuumLock to walk the worker array, but that one
2349 : * can just be a shared lock.
2350 : */
2351 230144 : LWLockAcquire(AutovacuumScheduleLock, LW_EXCLUSIVE);
2352 230144 : LWLockAcquire(AutovacuumLock, LW_SHARED);
2353 :
2354 : /*
2355 : * Check whether the table is being vacuumed concurrently by another
2356 : * worker.
2357 : */
2358 230144 : skipit = false;
2359 723638 : dlist_foreach(iter, &AutoVacuumShmem->av_runningWorkers)
2360 : {
2361 494608 : WorkerInfo worker = dlist_container(WorkerInfoData, wi_links, iter.cur);
2362 :
2363 : /* ignore myself */
2364 494608 : if (worker == MyWorkerInfo)
2365 229636 : continue;
2366 :
2367 : /* ignore workers in other databases (unless table is shared) */
2368 264972 : if (!worker->wi_sharedrel && worker->wi_dboid != MyDatabaseId)
2369 92 : continue;
2370 :
2371 264880 : if (worker->wi_tableoid == relid)
2372 : {
2373 1114 : skipit = true;
2374 1114 : found_concurrent_worker = true;
2375 1114 : break;
2376 : }
2377 : }
2378 230144 : LWLockRelease(AutovacuumLock);
2379 230144 : if (skipit)
2380 : {
2381 1114 : LWLockRelease(AutovacuumScheduleLock);
2382 1114 : continue;
2383 : }
2384 :
2385 : /*
2386 : * Store the table's OID in shared memory before releasing the
2387 : * schedule lock, so that other workers don't try to vacuum it
2388 : * concurrently. (We claim it here so as not to hold
2389 : * AutovacuumScheduleLock while rechecking the stats.)
2390 : */
2391 229030 : MyWorkerInfo->wi_tableoid = relid;
2392 229030 : MyWorkerInfo->wi_sharedrel = isshared;
2393 229030 : LWLockRelease(AutovacuumScheduleLock);
2394 :
2395 : /*
2396 : * Check whether pgstat data still says we need to vacuum this table.
2397 : * It could have changed if something else processed the table while
2398 : * we weren't looking. This doesn't entirely close the race condition,
2399 : * but it is very small.
2400 : */
2401 229030 : MemoryContextSwitchTo(AutovacMemCxt);
2402 229030 : tab = table_recheck_autovac(relid, table_toast_map, pg_class_desc,
2403 : effective_multixact_freeze_max_age);
2404 229030 : if (tab == NULL)
2405 : {
2406 : /* someone else vacuumed the table, or it went away */
2407 248 : LWLockAcquire(AutovacuumScheduleLock, LW_EXCLUSIVE);
2408 248 : MyWorkerInfo->wi_tableoid = InvalidOid;
2409 248 : MyWorkerInfo->wi_sharedrel = false;
2410 248 : LWLockRelease(AutovacuumScheduleLock);
2411 248 : continue;
2412 : }
2413 :
2414 : /*
2415 : * Save the cost-related storage parameter values in global variables
2416 : * for reference when updating vacuum_cost_delay and vacuum_cost_limit
2417 : * during vacuuming this table.
2418 : */
2419 228782 : av_storage_param_cost_delay = tab->at_storage_param_vac_cost_delay;
2420 228782 : av_storage_param_cost_limit = tab->at_storage_param_vac_cost_limit;
2421 :
2422 : /*
2423 : * We only expect this worker to ever set the flag, so don't bother
2424 : * checking the return value. We shouldn't have to retry.
2425 : */
2426 228782 : if (tab->at_dobalance)
2427 228782 : pg_atomic_test_set_flag(&MyWorkerInfo->wi_dobalance);
2428 : else
2429 0 : pg_atomic_clear_flag(&MyWorkerInfo->wi_dobalance);
2430 :
2431 228782 : LWLockAcquire(AutovacuumLock, LW_SHARED);
2432 228782 : autovac_recalculate_workers_for_balance();
2433 228782 : LWLockRelease(AutovacuumLock);
2434 :
2435 : /*
2436 : * We wait until this point to update cost delay and cost limit
2437 : * values, even though we reloaded the configuration file above, so
2438 : * that we can take into account the cost-related storage parameters.
2439 : */
2440 228782 : VacuumUpdateCosts();
2441 :
2442 :
2443 : /* clean up memory before each iteration */
2444 228782 : MemoryContextReset(PortalContext);
2445 :
2446 : /*
2447 : * Save the relation name for a possible error message, to avoid a
2448 : * catalog lookup in case of an error. If any of these return NULL,
2449 : * then the relation has been dropped since last we checked; skip it.
2450 : * Note: they must live in a long-lived memory context because we call
2451 : * vacuum and analyze in different transactions.
2452 : */
2453 :
2454 228782 : tab->at_relname = get_rel_name(tab->at_relid);
2455 228782 : tab->at_nspname = get_namespace_name(get_rel_namespace(tab->at_relid));
2456 228782 : tab->at_datname = get_database_name(MyDatabaseId);
2457 228782 : if (!tab->at_relname || !tab->at_nspname || !tab->at_datname)
2458 0 : goto deleted;
2459 :
2460 : /*
2461 : * We will abort vacuuming the current table if something errors out,
2462 : * and continue with the next one in schedule; in particular, this
2463 : * happens if we are interrupted with SIGINT.
2464 : */
2465 228782 : PG_TRY();
2466 : {
2467 : /* Use PortalContext for any per-table allocations */
2468 228782 : MemoryContextSwitchTo(PortalContext);
2469 :
2470 : /* have at it */
2471 228782 : autovacuum_do_vac_analyze(tab, bstrategy);
2472 :
2473 : /*
2474 : * Clear a possible query-cancel signal, to avoid a late reaction
2475 : * to an automatically-sent signal because of vacuuming the
2476 : * current table (we're done with it, so it would make no sense to
2477 : * cancel at this point.)
2478 : */
2479 228778 : QueryCancelPending = false;
2480 : }
2481 0 : PG_CATCH();
2482 : {
2483 : /*
2484 : * Abort the transaction, start a new one, and proceed with the
2485 : * next table in our list.
2486 : */
2487 0 : HOLD_INTERRUPTS();
2488 0 : if (tab->at_params.options & VACOPT_VACUUM)
2489 0 : errcontext("automatic vacuum of table \"%s.%s.%s\"",
2490 : tab->at_datname, tab->at_nspname, tab->at_relname);
2491 : else
2492 0 : errcontext("automatic analyze of table \"%s.%s.%s\"",
2493 : tab->at_datname, tab->at_nspname, tab->at_relname);
2494 0 : EmitErrorReport();
2495 :
2496 : /* this resets ProcGlobal->statusFlags[i] too */
2497 0 : AbortOutOfAnyTransaction();
2498 0 : FlushErrorState();
2499 0 : MemoryContextReset(PortalContext);
2500 :
2501 : /* restart our transaction for the following operations */
2502 0 : StartTransactionCommand();
2503 0 : RESUME_INTERRUPTS();
2504 : }
2505 228778 : PG_END_TRY();
2506 :
2507 : /* Make sure we're back in AutovacMemCxt */
2508 228778 : MemoryContextSwitchTo(AutovacMemCxt);
2509 :
2510 228778 : did_vacuum = true;
2511 :
2512 : /* ProcGlobal->statusFlags[i] are reset at the next end of xact */
2513 :
2514 : /* be tidy */
2515 228778 : deleted:
2516 228778 : if (tab->at_datname != NULL)
2517 228778 : pfree(tab->at_datname);
2518 228778 : if (tab->at_nspname != NULL)
2519 228778 : pfree(tab->at_nspname);
2520 228778 : if (tab->at_relname != NULL)
2521 228778 : pfree(tab->at_relname);
2522 228778 : pfree(tab);
2523 :
2524 : /*
2525 : * Remove my info from shared memory. We set wi_dobalance on the
2526 : * assumption that we are more likely than not to vacuum a table with
2527 : * no cost-related storage parameters next, so we want to claim our
2528 : * share of I/O as soon as possible to avoid thrashing the global
2529 : * balance.
2530 : */
2531 228778 : LWLockAcquire(AutovacuumScheduleLock, LW_EXCLUSIVE);
2532 228778 : MyWorkerInfo->wi_tableoid = InvalidOid;
2533 228778 : MyWorkerInfo->wi_sharedrel = false;
2534 228778 : LWLockRelease(AutovacuumScheduleLock);
2535 228778 : pg_atomic_test_set_flag(&MyWorkerInfo->wi_dobalance);
2536 : }
2537 :
2538 4318 : list_free(table_oids);
2539 :
2540 : /*
2541 : * Perform additional work items, as requested by backends.
2542 : */
2543 4318 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
2544 1109726 : for (i = 0; i < NUM_WORKITEMS; i++)
2545 : {
2546 1105408 : AutoVacuumWorkItem *workitem = &AutoVacuumShmem->av_workItems[i];
2547 :
2548 1105408 : if (!workitem->avw_used)
2549 1105402 : continue;
2550 6 : if (workitem->avw_active)
2551 0 : continue;
2552 6 : if (workitem->avw_database != MyDatabaseId)
2553 0 : continue;
2554 :
2555 : /* claim this one, and release lock while performing it */
2556 6 : workitem->avw_active = true;
2557 6 : LWLockRelease(AutovacuumLock);
2558 :
2559 6 : perform_work_item(workitem);
2560 :
2561 : /*
2562 : * Check for config changes before acquiring lock for further jobs.
2563 : */
2564 6 : CHECK_FOR_INTERRUPTS();
2565 6 : if (ConfigReloadPending)
2566 : {
2567 0 : ConfigReloadPending = false;
2568 0 : ProcessConfigFile(PGC_SIGHUP);
2569 0 : VacuumUpdateCosts();
2570 : }
2571 :
2572 6 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
2573 :
2574 : /* and mark it done */
2575 6 : workitem->avw_active = false;
2576 6 : workitem->avw_used = false;
2577 : }
2578 4318 : LWLockRelease(AutovacuumLock);
2579 :
2580 : /*
2581 : * We leak table_toast_map here (among other things), but since we're
2582 : * going away soon, it's not a problem normally. But when using Valgrind,
2583 : * release some stuff to reduce complaints about leaked storage.
2584 : */
2585 : #ifdef USE_VALGRIND
2586 : hash_destroy(table_toast_map);
2587 : FreeTupleDesc(pg_class_desc);
2588 : if (bstrategy)
2589 : pfree(bstrategy);
2590 : #endif
2591 :
2592 : /* Run the rest in xact context, mainly to avoid Valgrind leak warnings */
2593 4318 : MemoryContextSwitchTo(TopTransactionContext);
2594 :
2595 : /*
2596 : * Update pg_database.datfrozenxid, and truncate pg_xact if possible. We
2597 : * only need to do this once, not after each table.
2598 : *
2599 : * Even if we didn't vacuum anything, it may still be important to do
2600 : * this, because one indirect effect of vac_update_datfrozenxid() is to
2601 : * update TransamVariables->xidVacLimit. That might need to be done even
2602 : * if we haven't vacuumed anything, because relations with older
2603 : * relfrozenxid values or other databases with older datfrozenxid values
2604 : * might have been dropped, allowing xidVacLimit to advance.
2605 : *
2606 : * However, it's also important not to do this blindly in all cases,
2607 : * because when autovacuum=off this will restart the autovacuum launcher.
2608 : * If we're not careful, an infinite loop can result, where workers find
2609 : * no work to do and restart the launcher, which starts another worker in
2610 : * the same database that finds no work to do. To prevent that, we skip
2611 : * this if (1) we found no work to do and (2) we skipped at least one
2612 : * table due to concurrent autovacuum activity. In that case, the other
2613 : * worker has already done it, or will do so when it finishes.
2614 : */
2615 4318 : if (did_vacuum || !found_concurrent_worker)
2616 4318 : vac_update_datfrozenxid();
2617 :
2618 : /* Finally close out the last transaction. */
2619 4318 : CommitTransactionCommand();
2620 4318 : }
2621 :
2622 : /*
2623 : * Execute a previously registered work item.
2624 : */
2625 : static void
2626 6 : perform_work_item(AutoVacuumWorkItem *workitem)
2627 : {
2628 6 : char *cur_datname = NULL;
2629 6 : char *cur_nspname = NULL;
2630 6 : char *cur_relname = NULL;
2631 :
2632 : /*
2633 : * Note we do not store table info in MyWorkerInfo, since this is not
2634 : * vacuuming proper.
2635 : */
2636 :
2637 : /*
2638 : * Save the relation name for a possible error message, to avoid a catalog
2639 : * lookup in case of an error. If any of these return NULL, then the
2640 : * relation has been dropped since last we checked; skip it.
2641 : */
2642 : Assert(CurrentMemoryContext == AutovacMemCxt);
2643 :
2644 6 : cur_relname = get_rel_name(workitem->avw_relation);
2645 6 : cur_nspname = get_namespace_name(get_rel_namespace(workitem->avw_relation));
2646 6 : cur_datname = get_database_name(MyDatabaseId);
2647 6 : if (!cur_relname || !cur_nspname || !cur_datname)
2648 0 : goto deleted2;
2649 :
2650 6 : autovac_report_workitem(workitem, cur_nspname, cur_relname);
2651 :
2652 : /* clean up memory before each work item */
2653 6 : MemoryContextReset(PortalContext);
2654 :
2655 : /*
2656 : * We will abort the current work item if something errors out, and
2657 : * continue with the next one; in particular, this happens if we are
2658 : * interrupted with SIGINT. Note that this means that the work item list
2659 : * can be lossy.
2660 : */
2661 6 : PG_TRY();
2662 : {
2663 : /* Use PortalContext for any per-work-item allocations */
2664 6 : MemoryContextSwitchTo(PortalContext);
2665 :
2666 : /*
2667 : * Have at it. Functions called here are responsible for any required
2668 : * user switch and sandbox.
2669 : */
2670 6 : switch (workitem->avw_type)
2671 : {
2672 6 : case AVW_BRINSummarizeRange:
2673 6 : DirectFunctionCall2(brin_summarize_range,
2674 : ObjectIdGetDatum(workitem->avw_relation),
2675 : Int64GetDatum((int64) workitem->avw_blockNumber));
2676 6 : break;
2677 0 : default:
2678 0 : elog(WARNING, "unrecognized work item found: type %d",
2679 : workitem->avw_type);
2680 0 : break;
2681 : }
2682 :
2683 : /*
2684 : * Clear a possible query-cancel signal, to avoid a late reaction to
2685 : * an automatically-sent signal because of vacuuming the current table
2686 : * (we're done with it, so it would make no sense to cancel at this
2687 : * point.)
2688 : */
2689 6 : QueryCancelPending = false;
2690 : }
2691 0 : PG_CATCH();
2692 : {
2693 : /*
2694 : * Abort the transaction, start a new one, and proceed with the next
2695 : * table in our list.
2696 : */
2697 0 : HOLD_INTERRUPTS();
2698 0 : errcontext("processing work entry for relation \"%s.%s.%s\"",
2699 : cur_datname, cur_nspname, cur_relname);
2700 0 : EmitErrorReport();
2701 :
2702 : /* this resets ProcGlobal->statusFlags[i] too */
2703 0 : AbortOutOfAnyTransaction();
2704 0 : FlushErrorState();
2705 0 : MemoryContextReset(PortalContext);
2706 :
2707 : /* restart our transaction for the following operations */
2708 0 : StartTransactionCommand();
2709 0 : RESUME_INTERRUPTS();
2710 : }
2711 6 : PG_END_TRY();
2712 :
2713 : /* Make sure we're back in AutovacMemCxt */
2714 6 : MemoryContextSwitchTo(AutovacMemCxt);
2715 :
2716 : /* We intentionally do not set did_vacuum here */
2717 :
2718 : /* be tidy */
2719 6 : deleted2:
2720 6 : if (cur_datname)
2721 6 : pfree(cur_datname);
2722 6 : if (cur_nspname)
2723 6 : pfree(cur_nspname);
2724 6 : if (cur_relname)
2725 6 : pfree(cur_relname);
2726 6 : }
2727 :
2728 : /*
2729 : * extract_autovac_opts
2730 : *
2731 : * Given a relation's pg_class tuple, return a palloc'd copy of the
2732 : * AutoVacOpts portion of reloptions, if set; otherwise, return NULL.
2733 : *
2734 : * Note: callers do not have a relation lock on the table at this point,
2735 : * so the table could have been dropped, and its catalog rows gone, after
2736 : * we acquired the pg_class row. If pg_class had a TOAST table, this would
2737 : * be a risk; fortunately, it doesn't.
2738 : */
2739 : static AutoVacOpts *
2740 704442 : extract_autovac_opts(HeapTuple tup, TupleDesc pg_class_desc)
2741 : {
2742 : bytea *relopts;
2743 : AutoVacOpts *av;
2744 :
2745 : Assert(((Form_pg_class) GETSTRUCT(tup))->relkind == RELKIND_RELATION ||
2746 : ((Form_pg_class) GETSTRUCT(tup))->relkind == RELKIND_MATVIEW ||
2747 : ((Form_pg_class) GETSTRUCT(tup))->relkind == RELKIND_TOASTVALUE);
2748 :
2749 704442 : relopts = extractRelOptions(tup, pg_class_desc, NULL);
2750 704442 : if (relopts == NULL)
2751 697776 : return NULL;
2752 :
2753 6666 : av = palloc(sizeof(AutoVacOpts));
2754 6666 : memcpy(av, &(((StdRdOptions *) relopts)->autovacuum), sizeof(AutoVacOpts));
2755 6666 : pfree(relopts);
2756 :
2757 6666 : return av;
2758 : }
2759 :
2760 :
2761 : /*
2762 : * table_recheck_autovac
2763 : *
2764 : * Recheck whether a table still needs vacuum or analyze. Return value is a
2765 : * valid autovac_table pointer if it does, NULL otherwise.
2766 : *
2767 : * Note that the returned autovac_table does not have the name fields set.
2768 : */
2769 : static autovac_table *
2770 229030 : table_recheck_autovac(Oid relid, HTAB *table_toast_map,
2771 : TupleDesc pg_class_desc,
2772 : int effective_multixact_freeze_max_age)
2773 : {
2774 : Form_pg_class classForm;
2775 : HeapTuple classTup;
2776 : bool dovacuum;
2777 : bool doanalyze;
2778 229030 : autovac_table *tab = NULL;
2779 : bool wraparound;
2780 : AutoVacOpts *avopts;
2781 229030 : bool free_avopts = false;
2782 :
2783 : /* fetch the relation's relcache entry */
2784 229030 : classTup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(relid));
2785 229030 : if (!HeapTupleIsValid(classTup))
2786 0 : return NULL;
2787 229030 : classForm = (Form_pg_class) GETSTRUCT(classTup);
2788 :
2789 : /*
2790 : * Get the applicable reloptions. If it is a TOAST table, try to get the
2791 : * main table reloptions if the toast table itself doesn't have.
2792 : */
2793 229030 : avopts = extract_autovac_opts(classTup, pg_class_desc);
2794 229030 : if (avopts)
2795 2834 : free_avopts = true;
2796 226196 : else if (classForm->relkind == RELKIND_TOASTVALUE &&
2797 : table_toast_map != NULL)
2798 : {
2799 : av_relation *hentry;
2800 : bool found;
2801 :
2802 83992 : hentry = hash_search(table_toast_map, &relid, HASH_FIND, &found);
2803 83992 : if (found && hentry->ar_hasrelopts)
2804 2816 : avopts = &hentry->ar_reloptions;
2805 : }
2806 :
2807 229030 : recheck_relation_needs_vacanalyze(relid, avopts, classForm,
2808 : effective_multixact_freeze_max_age,
2809 : &dovacuum, &doanalyze, &wraparound);
2810 :
2811 : /* OK, it needs something done */
2812 229030 : if (doanalyze || dovacuum)
2813 : {
2814 : int freeze_min_age;
2815 : int freeze_table_age;
2816 : int multixact_freeze_min_age;
2817 : int multixact_freeze_table_age;
2818 : int log_vacuum_min_duration;
2819 : int log_analyze_min_duration;
2820 :
2821 : /*
2822 : * Calculate the vacuum cost parameters and the freeze ages. If there
2823 : * are options set in pg_class.reloptions, use them; in the case of a
2824 : * toast table, try the main table too. Otherwise use the GUC
2825 : * defaults, autovacuum's own first and plain vacuum second.
2826 : */
2827 :
2828 : /* -1 in autovac setting means use log_autovacuum_min_duration */
2829 5646 : log_vacuum_min_duration = (avopts && avopts->log_vacuum_min_duration >= 0)
2830 : ? avopts->log_vacuum_min_duration
2831 234428 : : Log_autovacuum_min_duration;
2832 :
2833 : /* -1 in autovac setting means use log_autoanalyze_min_duration */
2834 5646 : log_analyze_min_duration = (avopts && avopts->log_analyze_min_duration >= 0)
2835 : ? avopts->log_analyze_min_duration
2836 234428 : : Log_autoanalyze_min_duration;
2837 :
2838 : /* these do not have autovacuum-specific settings */
2839 5646 : freeze_min_age = (avopts && avopts->freeze_min_age >= 0)
2840 : ? avopts->freeze_min_age
2841 234428 : : default_freeze_min_age;
2842 :
2843 5646 : freeze_table_age = (avopts && avopts->freeze_table_age >= 0)
2844 : ? avopts->freeze_table_age
2845 234428 : : default_freeze_table_age;
2846 :
2847 234428 : multixact_freeze_min_age = (avopts &&
2848 5646 : avopts->multixact_freeze_min_age >= 0)
2849 : ? avopts->multixact_freeze_min_age
2850 234428 : : default_multixact_freeze_min_age;
2851 :
2852 234428 : multixact_freeze_table_age = (avopts &&
2853 5646 : avopts->multixact_freeze_table_age >= 0)
2854 : ? avopts->multixact_freeze_table_age
2855 234428 : : default_multixact_freeze_table_age;
2856 :
2857 228782 : tab = palloc(sizeof(autovac_table));
2858 228782 : tab->at_relid = relid;
2859 228782 : tab->at_sharedrel = classForm->relisshared;
2860 :
2861 : /*
2862 : * Select VACUUM options. Note we don't say VACOPT_PROCESS_TOAST, so
2863 : * that vacuum() skips toast relations. Also note we tell vacuum() to
2864 : * skip vac_update_datfrozenxid(); we'll do that separately.
2865 : */
2866 228782 : tab->at_params.options =
2867 228782 : (dovacuum ? (VACOPT_VACUUM |
2868 : VACOPT_PROCESS_MAIN |
2869 228782 : VACOPT_SKIP_DATABASE_STATS) : 0) |
2870 228782 : (doanalyze ? VACOPT_ANALYZE : 0) |
2871 228782 : (!wraparound ? VACOPT_SKIP_LOCKED : 0);
2872 :
2873 : /*
2874 : * index_cleanup and truncate are unspecified at first in autovacuum.
2875 : * They will be filled in with usable values using their reloptions
2876 : * (or reloption defaults) later.
2877 : */
2878 228782 : tab->at_params.index_cleanup = VACOPTVALUE_UNSPECIFIED;
2879 228782 : tab->at_params.truncate = VACOPTVALUE_UNSPECIFIED;
2880 : /* As of now, we don't support parallel vacuum for autovacuum */
2881 228782 : tab->at_params.nworkers = -1;
2882 228782 : tab->at_params.freeze_min_age = freeze_min_age;
2883 228782 : tab->at_params.freeze_table_age = freeze_table_age;
2884 228782 : tab->at_params.multixact_freeze_min_age = multixact_freeze_min_age;
2885 228782 : tab->at_params.multixact_freeze_table_age = multixact_freeze_table_age;
2886 228782 : tab->at_params.is_wraparound = wraparound;
2887 228782 : tab->at_params.log_vacuum_min_duration = log_vacuum_min_duration;
2888 228782 : tab->at_params.log_analyze_min_duration = log_analyze_min_duration;
2889 228782 : tab->at_params.toast_parent = InvalidOid;
2890 :
2891 : /*
2892 : * Later, in vacuum_rel(), we check reloptions for any
2893 : * vacuum_max_eager_freeze_failure_rate override.
2894 : */
2895 228782 : tab->at_params.max_eager_freeze_failure_rate = vacuum_max_eager_freeze_failure_rate;
2896 228782 : tab->at_storage_param_vac_cost_limit = avopts ?
2897 228782 : avopts->vacuum_cost_limit : 0;
2898 228782 : tab->at_storage_param_vac_cost_delay = avopts ?
2899 228782 : avopts->vacuum_cost_delay : -1;
2900 228782 : tab->at_relname = NULL;
2901 228782 : tab->at_nspname = NULL;
2902 228782 : tab->at_datname = NULL;
2903 :
2904 : /*
2905 : * If any of the cost delay parameters has been set individually for
2906 : * this table, disable the balancing algorithm.
2907 : */
2908 228782 : tab->at_dobalance =
2909 234428 : !(avopts && (avopts->vacuum_cost_limit > 0 ||
2910 5646 : avopts->vacuum_cost_delay >= 0));
2911 : }
2912 :
2913 229030 : if (free_avopts)
2914 2834 : pfree(avopts);
2915 229030 : heap_freetuple(classTup);
2916 229030 : return tab;
2917 : }
2918 :
2919 : /*
2920 : * recheck_relation_needs_vacanalyze
2921 : *
2922 : * Subroutine for table_recheck_autovac.
2923 : *
2924 : * Fetch the pgstat of a relation and recheck whether a relation
2925 : * needs to be vacuumed or analyzed.
2926 : */
2927 : static void
2928 229030 : recheck_relation_needs_vacanalyze(Oid relid,
2929 : AutoVacOpts *avopts,
2930 : Form_pg_class classForm,
2931 : int effective_multixact_freeze_max_age,
2932 : bool *dovacuum,
2933 : bool *doanalyze,
2934 : bool *wraparound)
2935 : {
2936 : PgStat_StatTabEntry *tabentry;
2937 :
2938 : /* fetch the pgstat table entry */
2939 229030 : tabentry = pgstat_fetch_stat_tabentry_ext(classForm->relisshared,
2940 : relid);
2941 :
2942 229030 : relation_needs_vacanalyze(relid, avopts, classForm, tabentry,
2943 : effective_multixact_freeze_max_age,
2944 : dovacuum, doanalyze, wraparound);
2945 :
2946 : /* Release tabentry to avoid leakage */
2947 229030 : if (tabentry)
2948 228110 : pfree(tabentry);
2949 :
2950 : /* ignore ANALYZE for toast tables */
2951 229030 : if (classForm->relkind == RELKIND_TOASTVALUE)
2952 83992 : *doanalyze = false;
2953 229030 : }
2954 :
2955 : /*
2956 : * relation_needs_vacanalyze
2957 : *
2958 : * Check whether a relation needs to be vacuumed or analyzed; return each into
2959 : * "dovacuum" and "doanalyze", respectively. Also return whether the vacuum is
2960 : * being forced because of Xid or multixact wraparound.
2961 : *
2962 : * relopts is a pointer to the AutoVacOpts options (either for itself in the
2963 : * case of a plain table, or for either itself or its parent table in the case
2964 : * of a TOAST table), NULL if none; tabentry is the pgstats entry, which can be
2965 : * NULL.
2966 : *
2967 : * A table needs to be vacuumed if the number of dead tuples exceeds a
2968 : * threshold. This threshold is calculated as
2969 : *
2970 : * threshold = vac_base_thresh + vac_scale_factor * reltuples
2971 : * if (threshold > vac_max_thresh)
2972 : * threshold = vac_max_thresh;
2973 : *
2974 : * For analyze, the analysis done is that the number of tuples inserted,
2975 : * deleted and updated since the last analyze exceeds a threshold calculated
2976 : * in the same fashion as above. Note that the cumulative stats system stores
2977 : * the number of tuples (both live and dead) that there were as of the last
2978 : * analyze. This is asymmetric to the VACUUM case.
2979 : *
2980 : * We also force vacuum if the table's relfrozenxid is more than freeze_max_age
2981 : * transactions back, and if its relminmxid is more than
2982 : * multixact_freeze_max_age multixacts back.
2983 : *
2984 : * A table whose autovacuum_enabled option is false is
2985 : * automatically skipped (unless we have to vacuum it due to freeze_max_age).
2986 : * Thus autovacuum can be disabled for specific tables. Also, when the cumulative
2987 : * stats system does not have data about a table, it will be skipped.
2988 : *
2989 : * A table whose vac_base_thresh value is < 0 takes the base value from the
2990 : * autovacuum_vacuum_threshold GUC variable. Similarly, a vac_scale_factor
2991 : * value < 0 is substituted with the value of
2992 : * autovacuum_vacuum_scale_factor GUC variable. Ditto for analyze.
2993 : */
2994 : static void
2995 704442 : relation_needs_vacanalyze(Oid relid,
2996 : AutoVacOpts *relopts,
2997 : Form_pg_class classForm,
2998 : PgStat_StatTabEntry *tabentry,
2999 : int effective_multixact_freeze_max_age,
3000 : /* output params below */
3001 : bool *dovacuum,
3002 : bool *doanalyze,
3003 : bool *wraparound)
3004 : {
3005 : bool force_vacuum;
3006 : bool av_enabled;
3007 :
3008 : /* constants from reloptions or GUC variables */
3009 : int vac_base_thresh,
3010 : vac_max_thresh,
3011 : vac_ins_base_thresh,
3012 : anl_base_thresh;
3013 : float4 vac_scale_factor,
3014 : vac_ins_scale_factor,
3015 : anl_scale_factor;
3016 :
3017 : /* thresholds calculated from above constants */
3018 : float4 vacthresh,
3019 : vacinsthresh,
3020 : anlthresh;
3021 :
3022 : /* number of vacuum (resp. analyze) tuples at this time */
3023 : float4 vactuples,
3024 : instuples,
3025 : anltuples;
3026 :
3027 : /* freeze parameters */
3028 : int freeze_max_age;
3029 : int multixact_freeze_max_age;
3030 : TransactionId xidForceLimit;
3031 : TransactionId relfrozenxid;
3032 : MultiXactId multiForceLimit;
3033 :
3034 : Assert(classForm != NULL);
3035 : Assert(OidIsValid(relid));
3036 :
3037 : /*
3038 : * Determine vacuum/analyze equation parameters. We have two possible
3039 : * sources: the passed reloptions (which could be a main table or a toast
3040 : * table), or the autovacuum GUC variables.
3041 : */
3042 :
3043 : /* -1 in autovac setting means use plain vacuum_scale_factor */
3044 13242 : vac_scale_factor = (relopts && relopts->vacuum_scale_factor >= 0)
3045 0 : ? relopts->vacuum_scale_factor
3046 717684 : : autovacuum_vac_scale;
3047 :
3048 13242 : vac_base_thresh = (relopts && relopts->vacuum_threshold >= 0)
3049 : ? relopts->vacuum_threshold
3050 717684 : : autovacuum_vac_thresh;
3051 :
3052 : /* -1 is used to disable max threshold */
3053 13242 : vac_max_thresh = (relopts && relopts->vacuum_max_threshold >= -1)
3054 : ? relopts->vacuum_max_threshold
3055 717684 : : autovacuum_vac_max_thresh;
3056 :
3057 13242 : vac_ins_scale_factor = (relopts && relopts->vacuum_ins_scale_factor >= 0)
3058 0 : ? relopts->vacuum_ins_scale_factor
3059 717684 : : autovacuum_vac_ins_scale;
3060 :
3061 : /* -1 is used to disable insert vacuums */
3062 13242 : vac_ins_base_thresh = (relopts && relopts->vacuum_ins_threshold >= -1)
3063 : ? relopts->vacuum_ins_threshold
3064 717684 : : autovacuum_vac_ins_thresh;
3065 :
3066 13242 : anl_scale_factor = (relopts && relopts->analyze_scale_factor >= 0)
3067 0 : ? relopts->analyze_scale_factor
3068 717684 : : autovacuum_anl_scale;
3069 :
3070 13242 : anl_base_thresh = (relopts && relopts->analyze_threshold >= 0)
3071 : ? relopts->analyze_threshold
3072 717684 : : autovacuum_anl_thresh;
3073 :
3074 13242 : freeze_max_age = (relopts && relopts->freeze_max_age >= 0)
3075 0 : ? Min(relopts->freeze_max_age, autovacuum_freeze_max_age)
3076 717684 : : autovacuum_freeze_max_age;
3077 :
3078 13242 : multixact_freeze_max_age = (relopts && relopts->multixact_freeze_max_age >= 0)
3079 0 : ? Min(relopts->multixact_freeze_max_age, effective_multixact_freeze_max_age)
3080 717684 : : effective_multixact_freeze_max_age;
3081 :
3082 704442 : av_enabled = (relopts ? relopts->enabled : true);
3083 :
3084 : /* Force vacuum if table is at risk of wraparound */
3085 704442 : xidForceLimit = recentXid - freeze_max_age;
3086 704442 : if (xidForceLimit < FirstNormalTransactionId)
3087 0 : xidForceLimit -= FirstNormalTransactionId;
3088 704442 : relfrozenxid = classForm->relfrozenxid;
3089 1408884 : force_vacuum = (TransactionIdIsNormal(relfrozenxid) &&
3090 704442 : TransactionIdPrecedes(relfrozenxid, xidForceLimit));
3091 704442 : if (!force_vacuum)
3092 : {
3093 246634 : MultiXactId relminmxid = classForm->relminmxid;
3094 :
3095 246634 : multiForceLimit = recentMulti - multixact_freeze_max_age;
3096 246634 : if (multiForceLimit < FirstMultiXactId)
3097 0 : multiForceLimit -= FirstMultiXactId;
3098 493268 : force_vacuum = MultiXactIdIsValid(relminmxid) &&
3099 246634 : MultiXactIdPrecedes(relminmxid, multiForceLimit);
3100 : }
3101 704442 : *wraparound = force_vacuum;
3102 :
3103 : /* User disabled it in pg_class.reloptions? (But ignore if at risk) */
3104 704442 : if (!av_enabled && !force_vacuum)
3105 : {
3106 1872 : *doanalyze = false;
3107 1872 : *dovacuum = false;
3108 1872 : return;
3109 : }
3110 :
3111 : /*
3112 : * If we found stats for the table, and autovacuum is currently enabled,
3113 : * make a threshold-based decision whether to vacuum and/or analyze. If
3114 : * autovacuum is currently disabled, we must be here for anti-wraparound
3115 : * vacuuming only, so don't vacuum (or analyze) anything that's not being
3116 : * forced.
3117 : */
3118 702570 : if (tabentry && AutoVacuumingActive())
3119 693978 : {
3120 693978 : float4 pcnt_unfrozen = 1;
3121 693978 : float4 reltuples = classForm->reltuples;
3122 693978 : int32 relpages = classForm->relpages;
3123 693978 : int32 relallfrozen = classForm->relallfrozen;
3124 :
3125 693978 : vactuples = tabentry->dead_tuples;
3126 693978 : instuples = tabentry->ins_since_vacuum;
3127 693978 : anltuples = tabentry->mod_since_analyze;
3128 :
3129 : /* If the table hasn't yet been vacuumed, take reltuples as zero */
3130 693978 : if (reltuples < 0)
3131 2674 : reltuples = 0;
3132 :
3133 : /*
3134 : * If we have data for relallfrozen, calculate the unfrozen percentage
3135 : * of the table to modify insert scale factor. This helps us decide
3136 : * whether or not to vacuum an insert-heavy table based on the number
3137 : * of inserts to the more "active" part of the table.
3138 : */
3139 693978 : if (relpages > 0 && relallfrozen > 0)
3140 : {
3141 : /*
3142 : * It could be the stats were updated manually and relallfrozen >
3143 : * relpages. Clamp relallfrozen to relpages to avoid nonsensical
3144 : * calculations.
3145 : */
3146 269450 : relallfrozen = Min(relallfrozen, relpages);
3147 269450 : pcnt_unfrozen = 1 - ((float4) relallfrozen / relpages);
3148 : }
3149 :
3150 693978 : vacthresh = (float4) vac_base_thresh + vac_scale_factor * reltuples;
3151 693978 : if (vac_max_thresh >= 0 && vacthresh > (float4) vac_max_thresh)
3152 0 : vacthresh = (float4) vac_max_thresh;
3153 :
3154 693978 : vacinsthresh = (float4) vac_ins_base_thresh +
3155 693978 : vac_ins_scale_factor * reltuples * pcnt_unfrozen;
3156 693978 : anlthresh = (float4) anl_base_thresh + anl_scale_factor * reltuples;
3157 :
3158 : /*
3159 : * Note that we don't need to take special consideration for stat
3160 : * reset, because if that happens, the last vacuum and analyze counts
3161 : * will be reset too.
3162 : */
3163 693978 : if (vac_ins_base_thresh >= 0)
3164 693978 : elog(DEBUG3, "%s: vac: %.0f (threshold %.0f), ins: %.0f (threshold %.0f), anl: %.0f (threshold %.0f)",
3165 : NameStr(classForm->relname),
3166 : vactuples, vacthresh, instuples, vacinsthresh, anltuples, anlthresh);
3167 : else
3168 0 : elog(DEBUG3, "%s: vac: %.0f (threshold %.0f), ins: (disabled), anl: %.0f (threshold %.0f)",
3169 : NameStr(classForm->relname),
3170 : vactuples, vacthresh, anltuples, anlthresh);
3171 :
3172 : /* Determine if this table needs vacuum or analyze. */
3173 931658 : *dovacuum = force_vacuum || (vactuples > vacthresh) ||
3174 237680 : (vac_ins_base_thresh >= 0 && instuples > vacinsthresh);
3175 693978 : *doanalyze = (anltuples > anlthresh);
3176 : }
3177 : else
3178 : {
3179 : /*
3180 : * Skip a table not found in stat hash, unless we have to force vacuum
3181 : * for anti-wrap purposes. If it's not acted upon, there's no need to
3182 : * vacuum it.
3183 : */
3184 8592 : *dovacuum = force_vacuum;
3185 8592 : *doanalyze = false;
3186 : }
3187 :
3188 : /* ANALYZE refuses to work with pg_statistic */
3189 702570 : if (relid == StatisticRelationId)
3190 6418 : *doanalyze = false;
3191 : }
3192 :
3193 : /*
3194 : * autovacuum_do_vac_analyze
3195 : * Vacuum and/or analyze the specified table
3196 : *
3197 : * We expect the caller to have switched into a memory context that won't
3198 : * disappear at transaction commit.
3199 : */
3200 : static void
3201 228782 : autovacuum_do_vac_analyze(autovac_table *tab, BufferAccessStrategy bstrategy)
3202 : {
3203 : RangeVar *rangevar;
3204 : VacuumRelation *rel;
3205 : List *rel_list;
3206 : MemoryContext vac_context;
3207 : MemoryContext old_context;
3208 :
3209 : /* Let pgstat know what we're doing */
3210 228782 : autovac_report_activity(tab);
3211 :
3212 : /* Create a context that vacuum() can use as cross-transaction storage */
3213 228782 : vac_context = AllocSetContextCreate(CurrentMemoryContext,
3214 : "Vacuum",
3215 : ALLOCSET_DEFAULT_SIZES);
3216 :
3217 : /* Set up one VacuumRelation target, identified by OID, for vacuum() */
3218 228782 : old_context = MemoryContextSwitchTo(vac_context);
3219 228782 : rangevar = makeRangeVar(tab->at_nspname, tab->at_relname, -1);
3220 228782 : rel = makeVacuumRelation(rangevar, tab->at_relid, NIL);
3221 228782 : rel_list = list_make1(rel);
3222 228782 : MemoryContextSwitchTo(old_context);
3223 :
3224 228782 : vacuum(rel_list, tab->at_params, bstrategy, vac_context, true);
3225 :
3226 228778 : MemoryContextDelete(vac_context);
3227 228778 : }
3228 :
3229 : /*
3230 : * autovac_report_activity
3231 : * Report to pgstat what autovacuum is doing
3232 : *
3233 : * We send a SQL string corresponding to what the user would see if the
3234 : * equivalent command was to be issued manually.
3235 : *
3236 : * Note we assume that we are going to report the next command as soon as we're
3237 : * done with the current one, and exit right after the last one, so we don't
3238 : * bother to report "<IDLE>" or some such.
3239 : */
3240 : static void
3241 228782 : autovac_report_activity(autovac_table *tab)
3242 : {
3243 : #define MAX_AUTOVAC_ACTIV_LEN (NAMEDATALEN * 2 + 56)
3244 : char activity[MAX_AUTOVAC_ACTIV_LEN];
3245 : int len;
3246 :
3247 : /* Report the command and possible options */
3248 228782 : if (tab->at_params.options & VACOPT_VACUUM)
3249 228500 : snprintf(activity, MAX_AUTOVAC_ACTIV_LEN,
3250 : "autovacuum: VACUUM%s",
3251 228500 : tab->at_params.options & VACOPT_ANALYZE ? " ANALYZE" : "");
3252 : else
3253 282 : snprintf(activity, MAX_AUTOVAC_ACTIV_LEN,
3254 : "autovacuum: ANALYZE");
3255 :
3256 : /*
3257 : * Report the qualified name of the relation.
3258 : */
3259 228782 : len = strlen(activity);
3260 :
3261 228782 : snprintf(activity + len, MAX_AUTOVAC_ACTIV_LEN - len,
3262 : " %s.%s%s", tab->at_nspname, tab->at_relname,
3263 228782 : tab->at_params.is_wraparound ? " (to prevent wraparound)" : "");
3264 :
3265 : /* Set statement_timestamp() to current time for pg_stat_activity */
3266 228782 : SetCurrentStatementStartTimestamp();
3267 :
3268 228782 : pgstat_report_activity(STATE_RUNNING, activity);
3269 228782 : }
3270 :
3271 : /*
3272 : * autovac_report_workitem
3273 : * Report to pgstat that autovacuum is processing a work item
3274 : */
3275 : static void
3276 6 : autovac_report_workitem(AutoVacuumWorkItem *workitem,
3277 : const char *nspname, const char *relname)
3278 : {
3279 : char activity[MAX_AUTOVAC_ACTIV_LEN + 12 + 2];
3280 : char blk[12 + 2];
3281 : int len;
3282 :
3283 6 : switch (workitem->avw_type)
3284 : {
3285 6 : case AVW_BRINSummarizeRange:
3286 6 : snprintf(activity, MAX_AUTOVAC_ACTIV_LEN,
3287 : "autovacuum: BRIN summarize");
3288 6 : break;
3289 : }
3290 :
3291 : /*
3292 : * Report the qualified name of the relation, and the block number if any
3293 : */
3294 6 : len = strlen(activity);
3295 :
3296 6 : if (BlockNumberIsValid(workitem->avw_blockNumber))
3297 6 : snprintf(blk, sizeof(blk), " %u", workitem->avw_blockNumber);
3298 : else
3299 0 : blk[0] = '\0';
3300 :
3301 6 : snprintf(activity + len, MAX_AUTOVAC_ACTIV_LEN - len,
3302 : " %s.%s%s", nspname, relname, blk);
3303 :
3304 : /* Set statement_timestamp() to current time for pg_stat_activity */
3305 6 : SetCurrentStatementStartTimestamp();
3306 :
3307 6 : pgstat_report_activity(STATE_RUNNING, activity);
3308 6 : }
3309 :
3310 : /*
3311 : * AutoVacuumingActive
3312 : * Check GUC vars and report whether the autovacuum process should be
3313 : * running.
3314 : */
3315 : bool
3316 769348 : AutoVacuumingActive(void)
3317 : {
3318 769348 : if (!autovacuum_start_daemon || !pgstat_track_counts)
3319 9942 : return false;
3320 759406 : return true;
3321 : }
3322 :
3323 : /*
3324 : * Request one work item to the next autovacuum run processing our database.
3325 : * Return false if the request can't be recorded.
3326 : */
3327 : bool
3328 6 : AutoVacuumRequestWork(AutoVacuumWorkItemType type, Oid relationId,
3329 : BlockNumber blkno)
3330 : {
3331 : int i;
3332 6 : bool result = false;
3333 :
3334 6 : LWLockAcquire(AutovacuumLock, LW_EXCLUSIVE);
3335 :
3336 : /*
3337 : * Locate an unused work item and fill it with the given data.
3338 : */
3339 12 : for (i = 0; i < NUM_WORKITEMS; i++)
3340 : {
3341 12 : AutoVacuumWorkItem *workitem = &AutoVacuumShmem->av_workItems[i];
3342 :
3343 12 : if (workitem->avw_used)
3344 6 : continue;
3345 :
3346 6 : workitem->avw_used = true;
3347 6 : workitem->avw_active = false;
3348 6 : workitem->avw_type = type;
3349 6 : workitem->avw_database = MyDatabaseId;
3350 6 : workitem->avw_relation = relationId;
3351 6 : workitem->avw_blockNumber = blkno;
3352 6 : result = true;
3353 :
3354 : /* done */
3355 6 : break;
3356 : }
3357 :
3358 6 : LWLockRelease(AutovacuumLock);
3359 :
3360 6 : return result;
3361 : }
3362 :
3363 : /*
3364 : * autovac_init
3365 : * This is called at postmaster initialization.
3366 : *
3367 : * All we do here is annoy the user if he got it wrong.
3368 : */
3369 : void
3370 1734 : autovac_init(void)
3371 : {
3372 1734 : if (!autovacuum_start_daemon)
3373 242 : return;
3374 1492 : else if (!pgstat_track_counts)
3375 0 : ereport(WARNING,
3376 : (errmsg("autovacuum not started because of misconfiguration"),
3377 : errhint("Enable the \"track_counts\" option.")));
3378 : else
3379 1492 : check_av_worker_gucs();
3380 : }
3381 :
3382 : /*
3383 : * AutoVacuumShmemSize
3384 : * Compute space needed for autovacuum-related shared memory
3385 : */
3386 : Size
3387 6246 : AutoVacuumShmemSize(void)
3388 : {
3389 : Size size;
3390 :
3391 : /*
3392 : * Need the fixed struct and the array of WorkerInfoData.
3393 : */
3394 6246 : size = sizeof(AutoVacuumShmemStruct);
3395 6246 : size = MAXALIGN(size);
3396 6246 : size = add_size(size, mul_size(autovacuum_worker_slots,
3397 : sizeof(WorkerInfoData)));
3398 6246 : return size;
3399 : }
3400 :
3401 : /*
3402 : * AutoVacuumShmemInit
3403 : * Allocate and initialize autovacuum-related shared memory
3404 : */
3405 : void
3406 2182 : AutoVacuumShmemInit(void)
3407 : {
3408 : bool found;
3409 :
3410 2182 : AutoVacuumShmem = (AutoVacuumShmemStruct *)
3411 2182 : ShmemInitStruct("AutoVacuum Data",
3412 : AutoVacuumShmemSize(),
3413 : &found);
3414 :
3415 2182 : if (!IsUnderPostmaster)
3416 : {
3417 : WorkerInfo worker;
3418 : int i;
3419 :
3420 : Assert(!found);
3421 :
3422 2182 : AutoVacuumShmem->av_launcherpid = 0;
3423 2182 : dclist_init(&AutoVacuumShmem->av_freeWorkers);
3424 2182 : dlist_init(&AutoVacuumShmem->av_runningWorkers);
3425 2182 : AutoVacuumShmem->av_startingWorker = NULL;
3426 2182 : memset(AutoVacuumShmem->av_workItems, 0,
3427 : sizeof(AutoVacuumWorkItem) * NUM_WORKITEMS);
3428 :
3429 2182 : worker = (WorkerInfo) ((char *) AutoVacuumShmem +
3430 : MAXALIGN(sizeof(AutoVacuumShmemStruct)));
3431 :
3432 : /* initialize the WorkerInfo free list */
3433 26096 : for (i = 0; i < autovacuum_worker_slots; i++)
3434 : {
3435 23914 : dclist_push_head(&AutoVacuumShmem->av_freeWorkers,
3436 23914 : &worker[i].wi_links);
3437 23914 : pg_atomic_init_flag(&worker[i].wi_dobalance);
3438 : }
3439 :
3440 2182 : pg_atomic_init_u32(&AutoVacuumShmem->av_nworkersForBalance, 0);
3441 :
3442 : }
3443 : else
3444 : Assert(found);
3445 2182 : }
3446 :
3447 : /*
3448 : * GUC check_hook for autovacuum_work_mem
3449 : */
3450 : bool
3451 2262 : check_autovacuum_work_mem(int *newval, void **extra, GucSource source)
3452 : {
3453 : /*
3454 : * -1 indicates fallback.
3455 : *
3456 : * If we haven't yet changed the boot_val default of -1, just let it be.
3457 : * Autovacuum will look to maintenance_work_mem instead.
3458 : */
3459 2262 : if (*newval == -1)
3460 2258 : return true;
3461 :
3462 : /*
3463 : * We clamp manually-set values to at least 64kB. Since
3464 : * maintenance_work_mem is always set to at least this value, do the same
3465 : * here.
3466 : */
3467 4 : if (*newval < 64)
3468 4 : *newval = 64;
3469 :
3470 4 : return true;
3471 : }
3472 :
3473 : /*
3474 : * Returns whether there is a free autovacuum worker slot available.
3475 : */
3476 : static bool
3477 34422 : av_worker_available(void)
3478 : {
3479 : int free_slots;
3480 : int reserved_slots;
3481 :
3482 34422 : free_slots = dclist_count(&AutoVacuumShmem->av_freeWorkers);
3483 :
3484 34422 : reserved_slots = autovacuum_worker_slots - autovacuum_max_workers;
3485 34422 : reserved_slots = Max(0, reserved_slots);
3486 :
3487 34422 : return free_slots > reserved_slots;
3488 : }
3489 :
3490 : /*
3491 : * Emits a WARNING if autovacuum_worker_slots < autovacuum_max_workers.
3492 : */
3493 : static void
3494 1492 : check_av_worker_gucs(void)
3495 : {
3496 1492 : if (autovacuum_worker_slots < autovacuum_max_workers)
3497 0 : ereport(WARNING,
3498 : (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3499 : errmsg("\"autovacuum_max_workers\" (%d) should be less than or equal to \"autovacuum_worker_slots\" (%d)",
3500 : autovacuum_max_workers, autovacuum_worker_slots),
3501 : errdetail("The server will only start up to \"autovacuum_worker_slots\" (%d) autovacuum workers at a given time.",
3502 : autovacuum_worker_slots)));
3503 1492 : }
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