Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * walreceiver.c
4 : *
5 : * The WAL receiver process (walreceiver) is new as of Postgres 9.0. It
6 : * is the process in the standby server that takes charge of receiving
7 : * XLOG records from a primary server during streaming replication.
8 : *
9 : * When the startup process determines that it's time to start streaming,
10 : * it instructs postmaster to start walreceiver. Walreceiver first connects
11 : * to the primary server (it will be served by a walsender process
12 : * in the primary server), and then keeps receiving XLOG records and
13 : * writing them to the disk as long as the connection is alive. As XLOG
14 : * records are received and flushed to disk, it updates the
15 : * WalRcv->flushedUpto variable in shared memory, to inform the startup
16 : * process of how far it can proceed with XLOG replay.
17 : *
18 : * A WAL receiver cannot directly load GUC parameters used when establishing
19 : * its connection to the primary. Instead it relies on parameter values
20 : * that are passed down by the startup process when streaming is requested.
21 : * This applies, for example, to the replication slot and the connection
22 : * string to be used for the connection with the primary.
23 : *
24 : * If the primary server ends streaming, but doesn't disconnect, walreceiver
25 : * goes into "waiting" mode, and waits for the startup process to give new
26 : * instructions. The startup process will treat that the same as
27 : * disconnection, and will rescan the archive/pg_wal directory. But when the
28 : * startup process wants to try streaming replication again, it will just
29 : * nudge the existing walreceiver process that's waiting, instead of launching
30 : * a new one.
31 : *
32 : * Normal termination is by SIGTERM, which instructs the walreceiver to
33 : * exit(0). Emergency termination is by SIGQUIT; like any postmaster child
34 : * process, the walreceiver will simply abort and exit on SIGQUIT. A close
35 : * of the connection and a FATAL error are treated not as a crash but as
36 : * normal operation.
37 : *
38 : * This file contains the server-facing parts of walreceiver. The libpq-
39 : * specific parts are in the libpqwalreceiver module. It's loaded
40 : * dynamically to avoid linking the server with libpq.
41 : *
42 : * Portions Copyright (c) 2010-2026, PostgreSQL Global Development Group
43 : *
44 : *
45 : * IDENTIFICATION
46 : * src/backend/replication/walreceiver.c
47 : *
48 : *-------------------------------------------------------------------------
49 : */
50 : #include "postgres.h"
51 :
52 : #include <unistd.h>
53 :
54 : #include "access/htup_details.h"
55 : #include "access/timeline.h"
56 : #include "access/transam.h"
57 : #include "access/xlog_internal.h"
58 : #include "access/xlogarchive.h"
59 : #include "access/xlogrecovery.h"
60 : #include "access/xlogwait.h"
61 : #include "catalog/pg_authid.h"
62 : #include "funcapi.h"
63 : #include "libpq/pqformat.h"
64 : #include "libpq/pqsignal.h"
65 : #include "miscadmin.h"
66 : #include "pgstat.h"
67 : #include "postmaster/auxprocess.h"
68 : #include "postmaster/interrupt.h"
69 : #include "replication/walreceiver.h"
70 : #include "replication/walsender.h"
71 : #include "storage/ipc.h"
72 : #include "storage/proc.h"
73 : #include "storage/procarray.h"
74 : #include "storage/procsignal.h"
75 : #include "tcop/tcopprot.h"
76 : #include "utils/acl.h"
77 : #include "utils/builtins.h"
78 : #include "utils/guc.h"
79 : #include "utils/pg_lsn.h"
80 : #include "utils/ps_status.h"
81 : #include "utils/timestamp.h"
82 : #include "utils/wait_event.h"
83 :
84 :
85 : /*
86 : * GUC variables. (Other variables that affect walreceiver are in xlog.c
87 : * because they're passed down from the startup process, for better
88 : * synchronization.)
89 : */
90 : int wal_receiver_status_interval;
91 : int wal_receiver_timeout;
92 : bool hot_standby_feedback;
93 :
94 : /* libpqwalreceiver connection */
95 : static WalReceiverConn *wrconn = NULL;
96 : WalReceiverFunctionsType *WalReceiverFunctions = NULL;
97 :
98 : /*
99 : * These variables are used similarly to openLogFile/SegNo,
100 : * but for walreceiver to write the XLOG. recvFileTLI is the TimeLineID
101 : * corresponding the filename of recvFile.
102 : */
103 : static int recvFile = -1;
104 : static TimeLineID recvFileTLI = 0;
105 : static XLogSegNo recvSegNo = 0;
106 :
107 : /*
108 : * LogstreamResult indicates the byte positions that we have already
109 : * written/fsynced.
110 : */
111 : static struct
112 : {
113 : XLogRecPtr Write; /* last byte + 1 written out in the standby */
114 : XLogRecPtr Flush; /* last byte + 1 flushed in the standby */
115 : } LogstreamResult;
116 :
117 : /*
118 : * Reasons to wake up and perform periodic tasks.
119 : */
120 : typedef enum WalRcvWakeupReason
121 : {
122 : WALRCV_WAKEUP_TERMINATE,
123 : WALRCV_WAKEUP_PING,
124 : WALRCV_WAKEUP_REPLY,
125 : WALRCV_WAKEUP_HSFEEDBACK,
126 : #define NUM_WALRCV_WAKEUPS (WALRCV_WAKEUP_HSFEEDBACK + 1)
127 : } WalRcvWakeupReason;
128 :
129 : /*
130 : * Wake up times for periodic tasks.
131 : */
132 : static TimestampTz wakeup[NUM_WALRCV_WAKEUPS];
133 :
134 : static StringInfoData reply_message;
135 :
136 : /* Prototypes for private functions */
137 : static void WalRcvFetchTimeLineHistoryFiles(TimeLineID first, TimeLineID last);
138 : static void WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI);
139 : static void WalRcvDie(int code, Datum arg);
140 : static void XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len,
141 : TimeLineID tli);
142 : static void XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr,
143 : TimeLineID tli);
144 : static void XLogWalRcvFlush(bool dying, TimeLineID tli);
145 : static void XLogWalRcvClose(XLogRecPtr recptr, TimeLineID tli);
146 : static void XLogWalRcvSendReply(bool force, bool requestReply);
147 : static void XLogWalRcvSendHSFeedback(bool immed);
148 : static void ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime);
149 : static void WalRcvComputeNextWakeup(WalRcvWakeupReason reason, TimestampTz now);
150 :
151 :
152 : /* Main entry point for walreceiver process */
153 : void
154 247 : WalReceiverMain(const void *startup_data, size_t startup_data_len)
155 : {
156 : char conninfo[MAXCONNINFO];
157 : char *tmp_conninfo;
158 : char slotname[NAMEDATALEN];
159 : bool is_temp_slot;
160 : XLogRecPtr startpoint;
161 : TimeLineID startpointTLI;
162 : TimeLineID primaryTLI;
163 : bool first_stream;
164 : WalRcvData *walrcv;
165 : TimestampTz now;
166 : char *err;
167 247 : char *sender_host = NULL;
168 247 : int sender_port = 0;
169 : char *appname;
170 :
171 : Assert(startup_data_len == 0);
172 :
173 247 : AuxiliaryProcessMainCommon();
174 :
175 : /*
176 : * WalRcv should be set up already (if we are a backend, we inherit this
177 : * by fork() or EXEC_BACKEND mechanism from the postmaster).
178 : */
179 247 : walrcv = WalRcv;
180 : Assert(walrcv != NULL);
181 :
182 : /*
183 : * Mark walreceiver as running in shared memory.
184 : *
185 : * Do this as early as possible, so that if we fail later on, we'll set
186 : * state to STOPPED. If we die before this, the startup process will keep
187 : * waiting for us to start up, until it times out.
188 : */
189 247 : SpinLockAcquire(&walrcv->mutex);
190 : Assert(walrcv->pid == 0);
191 247 : switch (walrcv->walRcvState)
192 : {
193 0 : case WALRCV_STOPPING:
194 : /* If we've already been requested to stop, don't start up. */
195 0 : walrcv->walRcvState = WALRCV_STOPPED;
196 : pg_fallthrough;
197 :
198 4 : case WALRCV_STOPPED:
199 4 : SpinLockRelease(&walrcv->mutex);
200 4 : ConditionVariableBroadcast(&walrcv->walRcvStoppedCV);
201 4 : proc_exit(1);
202 : break;
203 :
204 243 : case WALRCV_STARTING:
205 : /* The usual case */
206 243 : break;
207 :
208 0 : case WALRCV_CONNECTING:
209 : case WALRCV_WAITING:
210 : case WALRCV_STREAMING:
211 : case WALRCV_RESTARTING:
212 : default:
213 : /* Shouldn't happen */
214 0 : SpinLockRelease(&walrcv->mutex);
215 0 : elog(PANIC, "walreceiver still running according to shared memory state");
216 : }
217 : /* Advertise our PID so that the startup process can kill us */
218 243 : walrcv->pid = MyProcPid;
219 243 : walrcv->walRcvState = WALRCV_CONNECTING;
220 :
221 : /* Fetch information required to start streaming */
222 243 : walrcv->ready_to_display = false;
223 243 : strlcpy(conninfo, walrcv->conninfo, MAXCONNINFO);
224 243 : strlcpy(slotname, walrcv->slotname, NAMEDATALEN);
225 243 : is_temp_slot = walrcv->is_temp_slot;
226 243 : startpoint = walrcv->receiveStart;
227 243 : startpointTLI = walrcv->receiveStartTLI;
228 :
229 : /*
230 : * At most one of is_temp_slot and slotname can be set; otherwise,
231 : * RequestXLogStreaming messed up.
232 : */
233 : Assert(!is_temp_slot || (slotname[0] == '\0'));
234 :
235 : /* Initialise to a sanish value */
236 243 : now = GetCurrentTimestamp();
237 243 : walrcv->lastMsgSendTime =
238 243 : walrcv->lastMsgReceiptTime = walrcv->latestWalEndTime = now;
239 :
240 : /* Report our proc number so that others can wake us up */
241 243 : walrcv->procno = MyProcNumber;
242 :
243 243 : SpinLockRelease(&walrcv->mutex);
244 :
245 243 : pg_atomic_write_u64(&WalRcv->writtenUpto, 0);
246 :
247 : /* Arrange to clean up at walreceiver exit */
248 243 : on_shmem_exit(WalRcvDie, PointerGetDatum(&startpointTLI));
249 :
250 : /* Properly accept or ignore signals the postmaster might send us */
251 243 : pqsignal(SIGHUP, SignalHandlerForConfigReload); /* set flag to read config
252 : * file */
253 243 : pqsignal(SIGINT, SIG_IGN);
254 243 : pqsignal(SIGTERM, die); /* request shutdown */
255 : /* SIGQUIT handler was already set up by InitPostmasterChild */
256 243 : pqsignal(SIGALRM, SIG_IGN);
257 243 : pqsignal(SIGPIPE, SIG_IGN);
258 243 : pqsignal(SIGUSR1, procsignal_sigusr1_handler);
259 243 : pqsignal(SIGUSR2, SIG_IGN);
260 :
261 : /* Reset some signals that are accepted by postmaster but not here */
262 243 : pqsignal(SIGCHLD, SIG_DFL);
263 :
264 : /* Load the libpq-specific functions */
265 243 : load_file("libpqwalreceiver", false);
266 243 : if (WalReceiverFunctions == NULL)
267 0 : elog(ERROR, "libpqwalreceiver didn't initialize correctly");
268 :
269 : /* Unblock signals (they were blocked when the postmaster forked us) */
270 243 : sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
271 :
272 : /* Establish the connection to the primary for XLOG streaming */
273 243 : appname = cluster_name[0] ? cluster_name : "walreceiver";
274 243 : wrconn = walrcv_connect(conninfo, true, false, false, appname, &err);
275 243 : if (!wrconn)
276 98 : ereport(ERROR,
277 : (errcode(ERRCODE_CONNECTION_FAILURE),
278 : errmsg("streaming replication receiver \"%s\" could not connect to the primary server: %s",
279 : appname, err)));
280 :
281 : /*
282 : * Save user-visible connection string. This clobbers the original
283 : * conninfo, for security. Also save host and port of the sender server
284 : * this walreceiver is connected to.
285 : */
286 145 : tmp_conninfo = walrcv_get_conninfo(wrconn);
287 145 : walrcv_get_senderinfo(wrconn, &sender_host, &sender_port);
288 145 : SpinLockAcquire(&walrcv->mutex);
289 145 : memset(walrcv->conninfo, 0, MAXCONNINFO);
290 145 : if (tmp_conninfo)
291 145 : strlcpy(walrcv->conninfo, tmp_conninfo, MAXCONNINFO);
292 :
293 145 : memset(walrcv->sender_host, 0, NI_MAXHOST);
294 145 : if (sender_host)
295 145 : strlcpy(walrcv->sender_host, sender_host, NI_MAXHOST);
296 :
297 145 : walrcv->sender_port = sender_port;
298 145 : walrcv->ready_to_display = true;
299 145 : SpinLockRelease(&walrcv->mutex);
300 :
301 145 : if (tmp_conninfo)
302 145 : pfree(tmp_conninfo);
303 :
304 145 : if (sender_host)
305 145 : pfree(sender_host);
306 :
307 145 : first_stream = true;
308 : for (;;)
309 12 : {
310 : char *primary_sysid;
311 : char standby_sysid[32];
312 : WalRcvStreamOptions options;
313 :
314 : /*
315 : * Check that we're connected to a valid server using the
316 : * IDENTIFY_SYSTEM replication command.
317 : */
318 157 : primary_sysid = walrcv_identify_system(wrconn, &primaryTLI);
319 :
320 157 : snprintf(standby_sysid, sizeof(standby_sysid), UINT64_FORMAT,
321 : GetSystemIdentifier());
322 157 : if (strcmp(primary_sysid, standby_sysid) != 0)
323 : {
324 0 : ereport(ERROR,
325 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
326 : errmsg("database system identifier differs between the primary and standby"),
327 : errdetail("The primary's identifier is %s, the standby's identifier is %s.",
328 : primary_sysid, standby_sysid)));
329 : }
330 :
331 : /*
332 : * Confirm that the current timeline of the primary is the same or
333 : * ahead of ours.
334 : */
335 157 : if (primaryTLI < startpointTLI)
336 0 : ereport(ERROR,
337 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
338 : errmsg("highest timeline %u of the primary is behind recovery timeline %u",
339 : primaryTLI, startpointTLI)));
340 :
341 : /*
342 : * Get any missing history files. We do this always, even when we're
343 : * not interested in that timeline, so that if we're promoted to
344 : * become the primary later on, we don't select the same timeline that
345 : * was already used in the current primary. This isn't bullet-proof -
346 : * you'll need some external software to manage your cluster if you
347 : * need to ensure that a unique timeline id is chosen in every case,
348 : * but let's avoid the confusion of timeline id collisions where we
349 : * can.
350 : */
351 157 : WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
352 :
353 : /*
354 : * Create temporary replication slot if requested, and update slot
355 : * name in shared memory. (Note the slot name cannot already be set
356 : * in this case.)
357 : */
358 157 : if (is_temp_slot)
359 : {
360 0 : snprintf(slotname, sizeof(slotname),
361 : "pg_walreceiver_%lld",
362 0 : (long long int) walrcv_get_backend_pid(wrconn));
363 :
364 0 : walrcv_create_slot(wrconn, slotname, true, false, false, 0, NULL);
365 :
366 0 : SpinLockAcquire(&walrcv->mutex);
367 0 : strlcpy(walrcv->slotname, slotname, NAMEDATALEN);
368 0 : SpinLockRelease(&walrcv->mutex);
369 : }
370 :
371 : /*
372 : * Start streaming.
373 : *
374 : * We'll try to start at the requested starting point and timeline,
375 : * even if it's different from the server's latest timeline. In case
376 : * we've already reached the end of the old timeline, the server will
377 : * finish the streaming immediately, and we will go back to await
378 : * orders from the startup process. If recovery_target_timeline is
379 : * 'latest', the startup process will scan pg_wal and find the new
380 : * history file, bump recovery target timeline, and ask us to restart
381 : * on the new timeline.
382 : */
383 157 : options.logical = false;
384 157 : options.startpoint = startpoint;
385 157 : options.slotname = slotname[0] != '\0' ? slotname : NULL;
386 157 : options.proto.physical.startpointTLI = startpointTLI;
387 157 : if (walrcv_startstreaming(wrconn, &options))
388 : {
389 155 : if (first_stream)
390 143 : ereport(LOG,
391 : errmsg("started streaming WAL from primary at %X/%08X on timeline %u",
392 : LSN_FORMAT_ARGS(startpoint), startpointTLI));
393 : else
394 12 : ereport(LOG,
395 : errmsg("restarted WAL streaming at %X/%08X on timeline %u",
396 : LSN_FORMAT_ARGS(startpoint), startpointTLI));
397 155 : first_stream = false;
398 :
399 : /*
400 : * Switch to STREAMING after a successful connection if current
401 : * state is CONNECTING. This switch happens after an initial
402 : * startup, or after a restart as determined by
403 : * WalRcvWaitForStartPosition().
404 : */
405 155 : SpinLockAcquire(&walrcv->mutex);
406 155 : if (walrcv->walRcvState == WALRCV_CONNECTING)
407 155 : walrcv->walRcvState = WALRCV_STREAMING;
408 155 : SpinLockRelease(&walrcv->mutex);
409 :
410 : /* Initialize LogstreamResult and buffers for processing messages */
411 155 : LogstreamResult.Write = LogstreamResult.Flush = GetXLogReplayRecPtr(NULL);
412 155 : initStringInfo(&reply_message);
413 :
414 : /* Initialize nap wakeup times. */
415 155 : now = GetCurrentTimestamp();
416 775 : for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
417 620 : WalRcvComputeNextWakeup(i, now);
418 :
419 : /* Send initial reply/feedback messages. */
420 155 : XLogWalRcvSendReply(true, false);
421 155 : XLogWalRcvSendHSFeedback(true);
422 :
423 : /* Loop until end-of-streaming or error */
424 : for (;;)
425 55271 : {
426 : char *buf;
427 : int len;
428 55426 : bool endofwal = false;
429 55426 : pgsocket wait_fd = PGINVALID_SOCKET;
430 : int rc;
431 : TimestampTz nextWakeup;
432 : long nap;
433 :
434 : /*
435 : * Exit walreceiver if we're not in recovery. This should not
436 : * happen, but cross-check the status here.
437 : */
438 55426 : if (!RecoveryInProgress())
439 0 : ereport(FATAL,
440 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
441 : errmsg("cannot continue WAL streaming, recovery has already ended")));
442 :
443 : /* Process any requests or signals received recently */
444 55426 : CHECK_FOR_INTERRUPTS();
445 :
446 55425 : if (ConfigReloadPending)
447 : {
448 26 : ConfigReloadPending = false;
449 26 : ProcessConfigFile(PGC_SIGHUP);
450 : /* recompute wakeup times */
451 26 : now = GetCurrentTimestamp();
452 130 : for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
453 104 : WalRcvComputeNextWakeup(i, now);
454 26 : XLogWalRcvSendHSFeedback(true);
455 : }
456 :
457 : /* See if we can read data immediately */
458 55425 : len = walrcv_receive(wrconn, &buf, &wait_fd);
459 55398 : if (len != 0)
460 : {
461 : /*
462 : * Process the received data, and any subsequent data we
463 : * can read without blocking.
464 : */
465 : for (;;)
466 : {
467 144745 : if (len > 0)
468 : {
469 : /*
470 : * Something was received from primary, so adjust
471 : * the ping and terminate wakeup times.
472 : */
473 104978 : now = GetCurrentTimestamp();
474 104978 : WalRcvComputeNextWakeup(WALRCV_WAKEUP_TERMINATE,
475 : now);
476 104978 : WalRcvComputeNextWakeup(WALRCV_WAKEUP_PING, now);
477 104978 : XLogWalRcvProcessMsg(buf[0], &buf[1], len - 1,
478 : startpointTLI);
479 : }
480 39767 : else if (len == 0)
481 39723 : break;
482 44 : else if (len < 0)
483 : {
484 44 : ereport(LOG,
485 : (errmsg("replication terminated by primary server"),
486 : errdetail("End of WAL reached on timeline %u at %X/%08X.",
487 : startpointTLI,
488 : LSN_FORMAT_ARGS(LogstreamResult.Write))));
489 44 : endofwal = true;
490 44 : break;
491 : }
492 104978 : len = walrcv_receive(wrconn, &buf, &wait_fd);
493 : }
494 :
495 : /* Let the primary know that we received some data. */
496 39767 : XLogWalRcvSendReply(false, false);
497 :
498 : /*
499 : * If we've written some records, flush them to disk and
500 : * let the startup process and primary server know about
501 : * them.
502 : */
503 39767 : XLogWalRcvFlush(false, startpointTLI);
504 : }
505 :
506 : /* Check if we need to exit the streaming loop. */
507 55397 : if (endofwal)
508 44 : break;
509 :
510 : /* Find the soonest wakeup time, to limit our nap. */
511 55353 : nextWakeup = TIMESTAMP_INFINITY;
512 276765 : for (int i = 0; i < NUM_WALRCV_WAKEUPS; ++i)
513 221412 : nextWakeup = Min(wakeup[i], nextWakeup);
514 :
515 : /* Calculate the nap time, clamping as necessary. */
516 55353 : now = GetCurrentTimestamp();
517 55353 : nap = TimestampDifferenceMilliseconds(now, nextWakeup);
518 :
519 : /*
520 : * Ideally we would reuse a WaitEventSet object repeatedly
521 : * here to avoid the overheads of WaitLatchOrSocket on epoll
522 : * systems, but we can't be sure that libpq (or any other
523 : * walreceiver implementation) has the same socket (even if
524 : * the fd is the same number, it may have been closed and
525 : * reopened since the last time). In future, if there is a
526 : * function for removing sockets from WaitEventSet, then we
527 : * could add and remove just the socket each time, potentially
528 : * avoiding some system calls.
529 : */
530 : Assert(wait_fd != PGINVALID_SOCKET);
531 55353 : rc = WaitLatchOrSocket(MyLatch,
532 : WL_EXIT_ON_PM_DEATH | WL_SOCKET_READABLE |
533 : WL_TIMEOUT | WL_LATCH_SET,
534 : wait_fd,
535 : nap,
536 : WAIT_EVENT_WAL_RECEIVER_MAIN);
537 55353 : if (rc & WL_LATCH_SET)
538 : {
539 12498 : ResetLatch(MyLatch);
540 12498 : CHECK_FOR_INTERRUPTS();
541 :
542 12416 : if (walrcv->force_reply)
543 : {
544 : /*
545 : * The recovery process has asked us to send apply
546 : * feedback now. Make sure the flag is really set to
547 : * false in shared memory before sending the reply, so
548 : * we don't miss a new request for a reply.
549 : */
550 12363 : walrcv->force_reply = false;
551 12363 : pg_memory_barrier();
552 12363 : XLogWalRcvSendReply(true, false);
553 : }
554 : }
555 55271 : if (rc & WL_TIMEOUT)
556 : {
557 : /*
558 : * We didn't receive anything new. If we haven't heard
559 : * anything from the server for more than
560 : * wal_receiver_timeout / 2, ping the server. Also, if
561 : * it's been longer than wal_receiver_status_interval
562 : * since the last update we sent, send a status update to
563 : * the primary anyway, to report any progress in applying
564 : * WAL.
565 : */
566 5 : bool requestReply = false;
567 :
568 : /*
569 : * Report pending statistics to the cumulative stats
570 : * system. This location is useful for the report as it
571 : * is not within a tight loop in the WAL receiver, to
572 : * avoid bloating pgstats with requests, while also making
573 : * sure that the reports happen each time a status update
574 : * is sent.
575 : */
576 5 : pgstat_report_wal(false);
577 :
578 : /*
579 : * Check if time since last receive from primary has
580 : * reached the configured limit.
581 : */
582 5 : now = GetCurrentTimestamp();
583 5 : if (now >= wakeup[WALRCV_WAKEUP_TERMINATE])
584 0 : ereport(ERROR,
585 : (errcode(ERRCODE_CONNECTION_FAILURE),
586 : errmsg("terminating walreceiver due to timeout")));
587 :
588 : /*
589 : * If we didn't receive anything new for half of receiver
590 : * replication timeout, then ping the server.
591 : */
592 5 : if (now >= wakeup[WALRCV_WAKEUP_PING])
593 : {
594 0 : requestReply = true;
595 0 : wakeup[WALRCV_WAKEUP_PING] = TIMESTAMP_INFINITY;
596 : }
597 :
598 5 : XLogWalRcvSendReply(requestReply, requestReply);
599 5 : XLogWalRcvSendHSFeedback(false);
600 : }
601 : }
602 :
603 : /*
604 : * The backend finished streaming. Exit streaming COPY-mode from
605 : * our side, too.
606 : */
607 44 : walrcv_endstreaming(wrconn, &primaryTLI);
608 :
609 : /*
610 : * If the server had switched to a new timeline that we didn't
611 : * know about when we began streaming, fetch its timeline history
612 : * file now.
613 : */
614 12 : WalRcvFetchTimeLineHistoryFiles(startpointTLI, primaryTLI);
615 : }
616 : else
617 0 : ereport(LOG,
618 : (errmsg("primary server contains no more WAL on requested timeline %u",
619 : startpointTLI)));
620 :
621 : /*
622 : * End of WAL reached on the requested timeline. Close the last
623 : * segment, and await for new orders from the startup process.
624 : */
625 12 : if (recvFile >= 0)
626 : {
627 : char xlogfname[MAXFNAMELEN];
628 :
629 11 : XLogWalRcvFlush(false, startpointTLI);
630 11 : XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
631 11 : if (close(recvFile) != 0)
632 0 : ereport(PANIC,
633 : (errcode_for_file_access(),
634 : errmsg("could not close WAL segment %s: %m",
635 : xlogfname)));
636 :
637 : /*
638 : * Create .done file forcibly to prevent the streamed segment from
639 : * being archived later.
640 : */
641 11 : if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
642 11 : XLogArchiveForceDone(xlogfname);
643 : else
644 0 : XLogArchiveNotify(xlogfname);
645 : }
646 12 : recvFile = -1;
647 :
648 12 : elog(DEBUG1, "walreceiver ended streaming and awaits new instructions");
649 12 : WalRcvWaitForStartPosition(&startpoint, &startpointTLI);
650 : }
651 : /* not reached */
652 : }
653 :
654 : /*
655 : * Wait for startup process to set receiveStart and receiveStartTLI.
656 : */
657 : static void
658 12 : WalRcvWaitForStartPosition(XLogRecPtr *startpoint, TimeLineID *startpointTLI)
659 : {
660 12 : WalRcvData *walrcv = WalRcv;
661 : int state;
662 :
663 12 : SpinLockAcquire(&walrcv->mutex);
664 12 : state = walrcv->walRcvState;
665 12 : if (state != WALRCV_STREAMING && state != WALRCV_CONNECTING)
666 : {
667 0 : SpinLockRelease(&walrcv->mutex);
668 0 : if (state == WALRCV_STOPPING)
669 0 : proc_exit(0);
670 : else
671 0 : elog(FATAL, "unexpected walreceiver state");
672 : }
673 12 : walrcv->walRcvState = WALRCV_WAITING;
674 12 : walrcv->receiveStart = InvalidXLogRecPtr;
675 12 : walrcv->receiveStartTLI = 0;
676 12 : SpinLockRelease(&walrcv->mutex);
677 :
678 12 : set_ps_display("idle");
679 :
680 : /*
681 : * nudge startup process to notice that we've stopped streaming and are
682 : * now waiting for instructions.
683 : */
684 12 : WakeupRecovery();
685 : for (;;)
686 : {
687 24 : ResetLatch(MyLatch);
688 :
689 24 : CHECK_FOR_INTERRUPTS();
690 :
691 24 : SpinLockAcquire(&walrcv->mutex);
692 : Assert(walrcv->walRcvState == WALRCV_RESTARTING ||
693 : walrcv->walRcvState == WALRCV_WAITING ||
694 : walrcv->walRcvState == WALRCV_STOPPING);
695 24 : if (walrcv->walRcvState == WALRCV_RESTARTING)
696 : {
697 : /*
698 : * No need to handle changes in primary_conninfo or
699 : * primary_slot_name here. Startup process will signal us to
700 : * terminate in case those change.
701 : */
702 12 : *startpoint = walrcv->receiveStart;
703 12 : *startpointTLI = walrcv->receiveStartTLI;
704 12 : walrcv->walRcvState = WALRCV_CONNECTING;
705 12 : SpinLockRelease(&walrcv->mutex);
706 12 : break;
707 : }
708 12 : if (walrcv->walRcvState == WALRCV_STOPPING)
709 : {
710 : /*
711 : * We should've received SIGTERM if the startup process wants us
712 : * to die, but might as well check it here too.
713 : */
714 0 : SpinLockRelease(&walrcv->mutex);
715 0 : exit(1);
716 : }
717 12 : SpinLockRelease(&walrcv->mutex);
718 :
719 12 : (void) WaitLatch(MyLatch, WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, 0,
720 : WAIT_EVENT_WAL_RECEIVER_WAIT_START);
721 : }
722 :
723 12 : if (update_process_title)
724 : {
725 : char activitymsg[50];
726 :
727 12 : snprintf(activitymsg, sizeof(activitymsg), "restarting at %X/%08X",
728 12 : LSN_FORMAT_ARGS(*startpoint));
729 12 : set_ps_display(activitymsg);
730 : }
731 12 : }
732 :
733 : /*
734 : * Fetch any missing timeline history files between 'first' and 'last'
735 : * (inclusive) from the server.
736 : */
737 : static void
738 169 : WalRcvFetchTimeLineHistoryFiles(TimeLineID first, TimeLineID last)
739 : {
740 : TimeLineID tli;
741 :
742 360 : for (tli = first; tli <= last; tli++)
743 : {
744 : /* there's no history file for timeline 1 */
745 191 : if (tli != 1 && !existsTimeLineHistory(tli))
746 : {
747 : char *fname;
748 : char *content;
749 : int len;
750 : char expectedfname[MAXFNAMELEN];
751 :
752 11 : ereport(LOG,
753 : (errmsg("fetching timeline history file for timeline %u from primary server",
754 : tli)));
755 :
756 11 : walrcv_readtimelinehistoryfile(wrconn, tli, &fname, &content, &len);
757 :
758 : /*
759 : * Check that the filename on the primary matches what we
760 : * calculated ourselves. This is just a sanity check, it should
761 : * always match.
762 : */
763 11 : TLHistoryFileName(expectedfname, tli);
764 11 : if (strcmp(fname, expectedfname) != 0)
765 0 : ereport(ERROR,
766 : (errcode(ERRCODE_PROTOCOL_VIOLATION),
767 : errmsg_internal("primary reported unexpected file name for timeline history file of timeline %u",
768 : tli)));
769 :
770 : /*
771 : * Write the file to pg_wal.
772 : */
773 11 : writeTimeLineHistoryFile(tli, content, len);
774 :
775 : /*
776 : * Mark the streamed history file as ready for archiving if
777 : * archive_mode is always.
778 : */
779 11 : if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
780 11 : XLogArchiveForceDone(fname);
781 : else
782 0 : XLogArchiveNotify(fname);
783 :
784 11 : pfree(fname);
785 11 : pfree(content);
786 : }
787 : }
788 169 : }
789 :
790 : /*
791 : * Mark us as STOPPED in shared memory at exit.
792 : */
793 : static void
794 243 : WalRcvDie(int code, Datum arg)
795 : {
796 243 : WalRcvData *walrcv = WalRcv;
797 243 : TimeLineID *startpointTLI_p = (TimeLineID *) DatumGetPointer(arg);
798 :
799 : Assert(*startpointTLI_p != 0);
800 :
801 : /* Ensure that all WAL records received are flushed to disk */
802 243 : XLogWalRcvFlush(true, *startpointTLI_p);
803 :
804 : /* Mark ourselves inactive in shared memory */
805 243 : SpinLockAcquire(&walrcv->mutex);
806 : Assert(walrcv->walRcvState == WALRCV_STREAMING ||
807 : walrcv->walRcvState == WALRCV_CONNECTING ||
808 : walrcv->walRcvState == WALRCV_RESTARTING ||
809 : walrcv->walRcvState == WALRCV_STARTING ||
810 : walrcv->walRcvState == WALRCV_WAITING ||
811 : walrcv->walRcvState == WALRCV_STOPPING);
812 : Assert(walrcv->pid == MyProcPid);
813 243 : walrcv->walRcvState = WALRCV_STOPPED;
814 243 : walrcv->pid = 0;
815 243 : walrcv->procno = INVALID_PROC_NUMBER;
816 243 : walrcv->ready_to_display = false;
817 243 : SpinLockRelease(&walrcv->mutex);
818 :
819 243 : ConditionVariableBroadcast(&walrcv->walRcvStoppedCV);
820 :
821 : /* Terminate the connection gracefully. */
822 243 : if (wrconn != NULL)
823 145 : walrcv_disconnect(wrconn);
824 :
825 : /* Wake up the startup process to notice promptly that we're gone */
826 243 : WakeupRecovery();
827 243 : }
828 :
829 : /*
830 : * Accept the message from XLOG stream, and process it.
831 : */
832 : static void
833 104978 : XLogWalRcvProcessMsg(unsigned char type, char *buf, Size len, TimeLineID tli)
834 : {
835 : int hdrlen;
836 : XLogRecPtr dataStart;
837 : XLogRecPtr walEnd;
838 : TimestampTz sendTime;
839 : bool replyRequested;
840 :
841 104978 : switch (type)
842 : {
843 104413 : case PqReplMsg_WALData:
844 : {
845 : StringInfoData incoming_message;
846 :
847 104413 : hdrlen = sizeof(int64) + sizeof(int64) + sizeof(int64);
848 104413 : if (len < hdrlen)
849 0 : ereport(ERROR,
850 : (errcode(ERRCODE_PROTOCOL_VIOLATION),
851 : errmsg_internal("invalid WAL message received from primary")));
852 :
853 : /* initialize a StringInfo with the given buffer */
854 104413 : initReadOnlyStringInfo(&incoming_message, buf, hdrlen);
855 :
856 : /* read the fields */
857 104413 : dataStart = pq_getmsgint64(&incoming_message);
858 104413 : walEnd = pq_getmsgint64(&incoming_message);
859 104413 : sendTime = pq_getmsgint64(&incoming_message);
860 104413 : ProcessWalSndrMessage(walEnd, sendTime);
861 :
862 104413 : buf += hdrlen;
863 104413 : len -= hdrlen;
864 104413 : XLogWalRcvWrite(buf, len, dataStart, tli);
865 104413 : break;
866 : }
867 565 : case PqReplMsg_Keepalive:
868 : {
869 : StringInfoData incoming_message;
870 :
871 565 : hdrlen = sizeof(int64) + sizeof(int64) + sizeof(char);
872 565 : if (len != hdrlen)
873 0 : ereport(ERROR,
874 : (errcode(ERRCODE_PROTOCOL_VIOLATION),
875 : errmsg_internal("invalid keepalive message received from primary")));
876 :
877 : /* initialize a StringInfo with the given buffer */
878 565 : initReadOnlyStringInfo(&incoming_message, buf, hdrlen);
879 :
880 : /* read the fields */
881 565 : walEnd = pq_getmsgint64(&incoming_message);
882 565 : sendTime = pq_getmsgint64(&incoming_message);
883 565 : replyRequested = pq_getmsgbyte(&incoming_message);
884 :
885 565 : ProcessWalSndrMessage(walEnd, sendTime);
886 :
887 : /* If the primary requested a reply, send one immediately */
888 565 : if (replyRequested)
889 565 : XLogWalRcvSendReply(true, false);
890 565 : break;
891 : }
892 0 : default:
893 0 : ereport(ERROR,
894 : (errcode(ERRCODE_PROTOCOL_VIOLATION),
895 : errmsg_internal("invalid replication message type %d",
896 : type)));
897 : }
898 104978 : }
899 :
900 : /*
901 : * Write XLOG data to disk.
902 : */
903 : static void
904 104413 : XLogWalRcvWrite(char *buf, Size nbytes, XLogRecPtr recptr, TimeLineID tli)
905 : {
906 : int startoff;
907 : int byteswritten;
908 : instr_time start;
909 :
910 : Assert(tli != 0);
911 :
912 209249 : while (nbytes > 0)
913 : {
914 : int segbytes;
915 :
916 : /* Close the current segment if it's completed */
917 104836 : if (recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size))
918 423 : XLogWalRcvClose(recptr, tli);
919 :
920 104836 : if (recvFile < 0)
921 : {
922 : /* Create/use new log file */
923 869 : XLByteToSeg(recptr, recvSegNo, wal_segment_size);
924 869 : recvFile = XLogFileInit(recvSegNo, tli);
925 869 : recvFileTLI = tli;
926 : }
927 :
928 : /* Calculate the start offset of the received logs */
929 104836 : startoff = XLogSegmentOffset(recptr, wal_segment_size);
930 :
931 104836 : if (startoff + nbytes > wal_segment_size)
932 423 : segbytes = wal_segment_size - startoff;
933 : else
934 104413 : segbytes = nbytes;
935 :
936 : /* OK to write the logs */
937 104836 : errno = 0;
938 :
939 : /*
940 : * Measure I/O timing to write WAL data, for pg_stat_io.
941 : */
942 104836 : start = pgstat_prepare_io_time(track_wal_io_timing);
943 :
944 104836 : pgstat_report_wait_start(WAIT_EVENT_WAL_WRITE);
945 104836 : byteswritten = pg_pwrite(recvFile, buf, segbytes, (pgoff_t) startoff);
946 104836 : pgstat_report_wait_end();
947 :
948 104836 : pgstat_count_io_op_time(IOOBJECT_WAL, IOCONTEXT_NORMAL,
949 : IOOP_WRITE, start, 1, byteswritten);
950 :
951 104836 : if (byteswritten <= 0)
952 : {
953 : char xlogfname[MAXFNAMELEN];
954 : int save_errno;
955 :
956 : /* if write didn't set errno, assume no disk space */
957 0 : if (errno == 0)
958 0 : errno = ENOSPC;
959 :
960 0 : save_errno = errno;
961 0 : XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
962 0 : errno = save_errno;
963 0 : ereport(PANIC,
964 : (errcode_for_file_access(),
965 : errmsg("could not write to WAL segment %s "
966 : "at offset %d, length %d: %m",
967 : xlogfname, startoff, segbytes)));
968 : }
969 :
970 : /* Update state for write */
971 104836 : recptr += byteswritten;
972 :
973 104836 : nbytes -= byteswritten;
974 104836 : buf += byteswritten;
975 :
976 104836 : LogstreamResult.Write = recptr;
977 : }
978 :
979 : /* Update shared-memory status */
980 104413 : pg_atomic_write_u64(&WalRcv->writtenUpto, LogstreamResult.Write);
981 :
982 : /*
983 : * If we wrote an LSN that someone was waiting for, notify the waiters.
984 : */
985 208826 : if (waitLSNState &&
986 104413 : (LogstreamResult.Write >=
987 104413 : pg_atomic_read_u64(&waitLSNState->minWaitedLSN[WAIT_LSN_TYPE_STANDBY_WRITE])))
988 2 : WaitLSNWakeup(WAIT_LSN_TYPE_STANDBY_WRITE, LogstreamResult.Write);
989 :
990 : /*
991 : * Close the current segment if it's fully written up in the last cycle of
992 : * the loop, to create its archive notification file soon. Otherwise WAL
993 : * archiving of the segment will be delayed until any data in the next
994 : * segment is received and written.
995 : */
996 104413 : if (recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size))
997 314 : XLogWalRcvClose(recptr, tli);
998 104413 : }
999 :
1000 : /*
1001 : * Flush the log to disk.
1002 : *
1003 : * If we're in the midst of dying, it's unwise to do anything that might throw
1004 : * an error, so we skip sending a reply in that case.
1005 : */
1006 : static void
1007 40758 : XLogWalRcvFlush(bool dying, TimeLineID tli)
1008 : {
1009 : Assert(tli != 0);
1010 :
1011 40758 : if (LogstreamResult.Flush < LogstreamResult.Write)
1012 : {
1013 40119 : WalRcvData *walrcv = WalRcv;
1014 :
1015 40119 : issue_xlog_fsync(recvFile, recvSegNo, tli);
1016 :
1017 40119 : LogstreamResult.Flush = LogstreamResult.Write;
1018 :
1019 : /* Update shared-memory status */
1020 40119 : SpinLockAcquire(&walrcv->mutex);
1021 40119 : if (walrcv->flushedUpto < LogstreamResult.Flush)
1022 : {
1023 40119 : walrcv->latestChunkStart = walrcv->flushedUpto;
1024 40119 : walrcv->flushedUpto = LogstreamResult.Flush;
1025 40119 : walrcv->receivedTLI = tli;
1026 : }
1027 40119 : SpinLockRelease(&walrcv->mutex);
1028 :
1029 : /*
1030 : * If we flushed an LSN that someone was waiting for, notify the
1031 : * waiters.
1032 : */
1033 80238 : if (waitLSNState &&
1034 40119 : (LogstreamResult.Flush >=
1035 40119 : pg_atomic_read_u64(&waitLSNState->minWaitedLSN[WAIT_LSN_TYPE_STANDBY_FLUSH])))
1036 2 : WaitLSNWakeup(WAIT_LSN_TYPE_STANDBY_FLUSH, LogstreamResult.Flush);
1037 :
1038 : /* Signal the startup process and walsender that new WAL has arrived */
1039 40119 : WakeupRecovery();
1040 40119 : if (AllowCascadeReplication())
1041 40119 : WalSndWakeup(true, false);
1042 :
1043 : /* Report XLOG streaming progress in PS display */
1044 40119 : if (update_process_title)
1045 : {
1046 : char activitymsg[50];
1047 :
1048 40119 : snprintf(activitymsg, sizeof(activitymsg), "streaming %X/%08X",
1049 40119 : LSN_FORMAT_ARGS(LogstreamResult.Write));
1050 40119 : set_ps_display(activitymsg);
1051 : }
1052 :
1053 : /* Also let the primary know that we made some progress */
1054 40119 : if (!dying)
1055 : {
1056 40118 : XLogWalRcvSendReply(false, false);
1057 40118 : XLogWalRcvSendHSFeedback(false);
1058 : }
1059 : }
1060 40758 : }
1061 :
1062 : /*
1063 : * Close the current segment.
1064 : *
1065 : * Flush the segment to disk before closing it. Otherwise we have to
1066 : * reopen and fsync it later.
1067 : *
1068 : * Create an archive notification file since the segment is known completed.
1069 : */
1070 : static void
1071 737 : XLogWalRcvClose(XLogRecPtr recptr, TimeLineID tli)
1072 : {
1073 : char xlogfname[MAXFNAMELEN];
1074 :
1075 : Assert(recvFile >= 0 && !XLByteInSeg(recptr, recvSegNo, wal_segment_size));
1076 : Assert(tli != 0);
1077 :
1078 : /*
1079 : * fsync() and close current file before we switch to next one. We would
1080 : * otherwise have to reopen this file to fsync it later
1081 : */
1082 737 : XLogWalRcvFlush(false, tli);
1083 :
1084 737 : XLogFileName(xlogfname, recvFileTLI, recvSegNo, wal_segment_size);
1085 :
1086 : /*
1087 : * XLOG segment files will be re-read by recovery in startup process soon,
1088 : * so we don't advise the OS to release cache pages associated with the
1089 : * file like XLogFileClose() does.
1090 : */
1091 737 : if (close(recvFile) != 0)
1092 0 : ereport(PANIC,
1093 : (errcode_for_file_access(),
1094 : errmsg("could not close WAL segment %s: %m",
1095 : xlogfname)));
1096 :
1097 : /*
1098 : * Create .done file forcibly to prevent the streamed segment from being
1099 : * archived later.
1100 : */
1101 737 : if (XLogArchiveMode != ARCHIVE_MODE_ALWAYS)
1102 737 : XLogArchiveForceDone(xlogfname);
1103 : else
1104 0 : XLogArchiveNotify(xlogfname);
1105 :
1106 737 : recvFile = -1;
1107 737 : }
1108 :
1109 : /*
1110 : * Send reply message to primary, indicating our current WAL locations, oldest
1111 : * xmin and the current time.
1112 : *
1113 : * If 'force' is not set, the message is only sent if enough time has
1114 : * passed since last status update to reach wal_receiver_status_interval.
1115 : * If wal_receiver_status_interval is disabled altogether and 'force' is
1116 : * false, this is a no-op.
1117 : *
1118 : * If 'requestReply' is true, requests the server to reply immediately upon
1119 : * receiving this message. This is used for heartbeats, when approaching
1120 : * wal_receiver_timeout.
1121 : */
1122 : static void
1123 92973 : XLogWalRcvSendReply(bool force, bool requestReply)
1124 : {
1125 : static XLogRecPtr writePtr = InvalidXLogRecPtr;
1126 : static XLogRecPtr flushPtr = InvalidXLogRecPtr;
1127 : XLogRecPtr applyPtr;
1128 : TimestampTz now;
1129 :
1130 : /*
1131 : * If the user doesn't want status to be reported to the primary, be sure
1132 : * to exit before doing anything at all.
1133 : */
1134 92973 : if (!force && wal_receiver_status_interval <= 0)
1135 0 : return;
1136 :
1137 : /* Get current timestamp. */
1138 92973 : now = GetCurrentTimestamp();
1139 :
1140 : /*
1141 : * We can compare the write and flush positions to the last message we
1142 : * sent without taking any lock, but the apply position requires a spin
1143 : * lock, so we don't check that unless something else has changed or 10
1144 : * seconds have passed. This means that the apply WAL location will
1145 : * appear, from the primary's point of view, to lag slightly, but since
1146 : * this is only for reporting purposes and only on idle systems, that's
1147 : * probably OK.
1148 : */
1149 92973 : if (!force
1150 79890 : && writePtr == LogstreamResult.Write
1151 39664 : && flushPtr == LogstreamResult.Flush
1152 283 : && now < wakeup[WALRCV_WAKEUP_REPLY])
1153 282 : return;
1154 :
1155 : /* Make sure we wake up when it's time to send another reply. */
1156 92691 : WalRcvComputeNextWakeup(WALRCV_WAKEUP_REPLY, now);
1157 :
1158 : /* Construct a new message */
1159 92691 : writePtr = LogstreamResult.Write;
1160 92691 : flushPtr = LogstreamResult.Flush;
1161 92691 : applyPtr = GetXLogReplayRecPtr(NULL);
1162 :
1163 92691 : resetStringInfo(&reply_message);
1164 92691 : pq_sendbyte(&reply_message, PqReplMsg_StandbyStatusUpdate);
1165 92691 : pq_sendint64(&reply_message, writePtr);
1166 92691 : pq_sendint64(&reply_message, flushPtr);
1167 92691 : pq_sendint64(&reply_message, applyPtr);
1168 92691 : pq_sendint64(&reply_message, GetCurrentTimestamp());
1169 92691 : pq_sendbyte(&reply_message, requestReply ? 1 : 0);
1170 :
1171 : /* Send it */
1172 92691 : elog(DEBUG2, "sending write %X/%08X flush %X/%08X apply %X/%08X%s",
1173 : LSN_FORMAT_ARGS(writePtr),
1174 : LSN_FORMAT_ARGS(flushPtr),
1175 : LSN_FORMAT_ARGS(applyPtr),
1176 : requestReply ? " (reply requested)" : "");
1177 :
1178 92691 : walrcv_send(wrconn, reply_message.data, reply_message.len);
1179 : }
1180 :
1181 : /*
1182 : * Send hot standby feedback message to primary, plus the current time,
1183 : * in case they don't have a watch.
1184 : *
1185 : * If the user disables feedback, send one final message to tell sender
1186 : * to forget about the xmin on this standby. We also send this message
1187 : * on first connect because a previous connection might have set xmin
1188 : * on a replication slot. (If we're not using a slot it's harmless to
1189 : * send a feedback message explicitly setting InvalidTransactionId).
1190 : */
1191 : static void
1192 40304 : XLogWalRcvSendHSFeedback(bool immed)
1193 : {
1194 : TimestampTz now;
1195 : FullTransactionId nextFullXid;
1196 : TransactionId nextXid;
1197 : uint32 xmin_epoch,
1198 : catalog_xmin_epoch;
1199 : TransactionId xmin,
1200 : catalog_xmin;
1201 :
1202 : /* initially true so we always send at least one feedback message */
1203 : static bool primary_has_standby_xmin = true;
1204 :
1205 : /*
1206 : * If the user doesn't want status to be reported to the primary, be sure
1207 : * to exit before doing anything at all.
1208 : */
1209 40304 : if ((wal_receiver_status_interval <= 0 || !hot_standby_feedback) &&
1210 39694 : !primary_has_standby_xmin)
1211 40136 : return;
1212 :
1213 : /* Get current timestamp. */
1214 783 : now = GetCurrentTimestamp();
1215 :
1216 : /* Send feedback at most once per wal_receiver_status_interval. */
1217 783 : if (!immed && now < wakeup[WALRCV_WAKEUP_HSFEEDBACK])
1218 614 : return;
1219 :
1220 : /* Make sure we wake up when it's time to send feedback again. */
1221 169 : WalRcvComputeNextWakeup(WALRCV_WAKEUP_HSFEEDBACK, now);
1222 :
1223 : /*
1224 : * If Hot Standby is not yet accepting connections there is nothing to
1225 : * send. Check this after the interval has expired to reduce number of
1226 : * calls.
1227 : *
1228 : * Bailing out here also ensures that we don't send feedback until we've
1229 : * read our own replication slot state, so we don't tell the primary to
1230 : * discard needed xmin or catalog_xmin from any slots that may exist on
1231 : * this replica.
1232 : */
1233 169 : if (!HotStandbyActive())
1234 1 : return;
1235 :
1236 : /*
1237 : * Make the expensive call to get the oldest xmin once we are certain
1238 : * everything else has been checked.
1239 : */
1240 168 : if (hot_standby_feedback)
1241 : {
1242 53 : GetReplicationHorizons(&xmin, &catalog_xmin);
1243 : }
1244 : else
1245 : {
1246 115 : xmin = InvalidTransactionId;
1247 115 : catalog_xmin = InvalidTransactionId;
1248 : }
1249 :
1250 : /*
1251 : * Get epoch and adjust if nextXid and oldestXmin are different sides of
1252 : * the epoch boundary.
1253 : */
1254 168 : nextFullXid = ReadNextFullTransactionId();
1255 168 : nextXid = XidFromFullTransactionId(nextFullXid);
1256 168 : xmin_epoch = EpochFromFullTransactionId(nextFullXid);
1257 168 : catalog_xmin_epoch = xmin_epoch;
1258 168 : if (nextXid < xmin)
1259 0 : xmin_epoch--;
1260 168 : if (nextXid < catalog_xmin)
1261 0 : catalog_xmin_epoch--;
1262 :
1263 168 : elog(DEBUG2, "sending hot standby feedback xmin %u epoch %u catalog_xmin %u catalog_xmin_epoch %u",
1264 : xmin, xmin_epoch, catalog_xmin, catalog_xmin_epoch);
1265 :
1266 : /* Construct the message and send it. */
1267 168 : resetStringInfo(&reply_message);
1268 168 : pq_sendbyte(&reply_message, PqReplMsg_HotStandbyFeedback);
1269 168 : pq_sendint64(&reply_message, GetCurrentTimestamp());
1270 168 : pq_sendint32(&reply_message, xmin);
1271 168 : pq_sendint32(&reply_message, xmin_epoch);
1272 168 : pq_sendint32(&reply_message, catalog_xmin);
1273 168 : pq_sendint32(&reply_message, catalog_xmin_epoch);
1274 168 : walrcv_send(wrconn, reply_message.data, reply_message.len);
1275 168 : if (TransactionIdIsValid(xmin) || TransactionIdIsValid(catalog_xmin))
1276 53 : primary_has_standby_xmin = true;
1277 : else
1278 115 : primary_has_standby_xmin = false;
1279 : }
1280 :
1281 : /*
1282 : * Update shared memory status upon receiving a message from primary.
1283 : *
1284 : * 'walEnd' and 'sendTime' are the end-of-WAL and timestamp of the latest
1285 : * message, reported by primary.
1286 : */
1287 : static void
1288 104978 : ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
1289 : {
1290 104978 : WalRcvData *walrcv = WalRcv;
1291 104978 : TimestampTz lastMsgReceiptTime = GetCurrentTimestamp();
1292 :
1293 : /* Update shared-memory status */
1294 104978 : SpinLockAcquire(&walrcv->mutex);
1295 104978 : if (walrcv->latestWalEnd < walEnd)
1296 21652 : walrcv->latestWalEndTime = sendTime;
1297 104978 : walrcv->latestWalEnd = walEnd;
1298 104978 : walrcv->lastMsgSendTime = sendTime;
1299 104978 : walrcv->lastMsgReceiptTime = lastMsgReceiptTime;
1300 104978 : SpinLockRelease(&walrcv->mutex);
1301 :
1302 104978 : if (message_level_is_interesting(DEBUG2))
1303 : {
1304 : char *sendtime;
1305 : char *receipttime;
1306 : int applyDelay;
1307 :
1308 : /* Copy because timestamptz_to_str returns a static buffer */
1309 407 : sendtime = pstrdup(timestamptz_to_str(sendTime));
1310 407 : receipttime = pstrdup(timestamptz_to_str(lastMsgReceiptTime));
1311 407 : applyDelay = GetReplicationApplyDelay();
1312 :
1313 : /* apply delay is not available */
1314 407 : if (applyDelay == -1)
1315 5 : elog(DEBUG2, "sendtime %s receipttime %s replication apply delay (N/A) transfer latency %d ms",
1316 : sendtime,
1317 : receipttime,
1318 : GetReplicationTransferLatency());
1319 : else
1320 402 : elog(DEBUG2, "sendtime %s receipttime %s replication apply delay %d ms transfer latency %d ms",
1321 : sendtime,
1322 : receipttime,
1323 : applyDelay,
1324 : GetReplicationTransferLatency());
1325 :
1326 407 : pfree(sendtime);
1327 407 : pfree(receipttime);
1328 : }
1329 104978 : }
1330 :
1331 : /*
1332 : * Compute the next wakeup time for a given wakeup reason. Can be called to
1333 : * initialize a wakeup time, to adjust it for the next wakeup, or to
1334 : * reinitialize it when GUCs have changed. We ask the caller to pass in the
1335 : * value of "now" because this frequently avoids multiple calls of
1336 : * GetCurrentTimestamp(). It had better be a reasonably up-to-date value
1337 : * though.
1338 : */
1339 : static void
1340 303540 : WalRcvComputeNextWakeup(WalRcvWakeupReason reason, TimestampTz now)
1341 : {
1342 303540 : switch (reason)
1343 : {
1344 105159 : case WALRCV_WAKEUP_TERMINATE:
1345 105159 : if (wal_receiver_timeout <= 0)
1346 0 : wakeup[reason] = TIMESTAMP_INFINITY;
1347 : else
1348 105159 : wakeup[reason] = TimestampTzPlusMilliseconds(now, wal_receiver_timeout);
1349 105159 : break;
1350 105159 : case WALRCV_WAKEUP_PING:
1351 105159 : if (wal_receiver_timeout <= 0)
1352 0 : wakeup[reason] = TIMESTAMP_INFINITY;
1353 : else
1354 105159 : wakeup[reason] = TimestampTzPlusMilliseconds(now, wal_receiver_timeout / 2);
1355 105159 : break;
1356 350 : case WALRCV_WAKEUP_HSFEEDBACK:
1357 350 : if (!hot_standby_feedback || wal_receiver_status_interval <= 0)
1358 249 : wakeup[reason] = TIMESTAMP_INFINITY;
1359 : else
1360 101 : wakeup[reason] = TimestampTzPlusSeconds(now, wal_receiver_status_interval);
1361 350 : break;
1362 92872 : case WALRCV_WAKEUP_REPLY:
1363 92872 : if (wal_receiver_status_interval <= 0)
1364 0 : wakeup[reason] = TIMESTAMP_INFINITY;
1365 : else
1366 92872 : wakeup[reason] = TimestampTzPlusSeconds(now, wal_receiver_status_interval);
1367 92872 : break;
1368 : /* there's intentionally no default: here */
1369 : }
1370 303540 : }
1371 :
1372 : /*
1373 : * Wake up the walreceiver main loop.
1374 : *
1375 : * This is called by the startup process whenever interesting xlog records
1376 : * are applied, so that walreceiver can check if it needs to send an apply
1377 : * notification back to the primary which may be waiting in a COMMIT with
1378 : * synchronous_commit = remote_apply.
1379 : */
1380 : void
1381 12294 : WalRcvForceReply(void)
1382 : {
1383 : ProcNumber procno;
1384 :
1385 12294 : WalRcv->force_reply = true;
1386 : /* fetching the proc number is probably atomic, but don't rely on it */
1387 12294 : SpinLockAcquire(&WalRcv->mutex);
1388 12294 : procno = WalRcv->procno;
1389 12294 : SpinLockRelease(&WalRcv->mutex);
1390 12294 : if (procno != INVALID_PROC_NUMBER)
1391 12121 : SetLatch(&GetPGProcByNumber(procno)->procLatch);
1392 12294 : }
1393 :
1394 : /*
1395 : * Return a string constant representing the state. This is used
1396 : * in system functions and views, and should *not* be translated.
1397 : */
1398 : static const char *
1399 11 : WalRcvGetStateString(WalRcvState state)
1400 : {
1401 11 : switch (state)
1402 : {
1403 0 : case WALRCV_STOPPED:
1404 0 : return "stopped";
1405 0 : case WALRCV_STARTING:
1406 0 : return "starting";
1407 0 : case WALRCV_CONNECTING:
1408 0 : return "connecting";
1409 11 : case WALRCV_STREAMING:
1410 11 : return "streaming";
1411 0 : case WALRCV_WAITING:
1412 0 : return "waiting";
1413 0 : case WALRCV_RESTARTING:
1414 0 : return "restarting";
1415 0 : case WALRCV_STOPPING:
1416 0 : return "stopping";
1417 : }
1418 0 : return "UNKNOWN";
1419 : }
1420 :
1421 : /*
1422 : * Returns activity of WAL receiver, including pid, state and xlog locations
1423 : * received from the WAL sender of another server.
1424 : */
1425 : Datum
1426 20 : pg_stat_get_wal_receiver(PG_FUNCTION_ARGS)
1427 : {
1428 : TupleDesc tupdesc;
1429 : Datum *values;
1430 : bool *nulls;
1431 : int pid;
1432 : bool ready_to_display;
1433 : WalRcvState state;
1434 : XLogRecPtr receive_start_lsn;
1435 : TimeLineID receive_start_tli;
1436 : XLogRecPtr written_lsn;
1437 : XLogRecPtr flushed_lsn;
1438 : TimeLineID received_tli;
1439 : TimestampTz last_send_time;
1440 : TimestampTz last_receipt_time;
1441 : XLogRecPtr latest_end_lsn;
1442 : TimestampTz latest_end_time;
1443 : char sender_host[NI_MAXHOST];
1444 20 : int sender_port = 0;
1445 : char slotname[NAMEDATALEN];
1446 : char conninfo[MAXCONNINFO];
1447 :
1448 : /* Take a lock to ensure value consistency */
1449 20 : SpinLockAcquire(&WalRcv->mutex);
1450 20 : pid = (int) WalRcv->pid;
1451 20 : ready_to_display = WalRcv->ready_to_display;
1452 20 : state = WalRcv->walRcvState;
1453 20 : receive_start_lsn = WalRcv->receiveStart;
1454 20 : receive_start_tli = WalRcv->receiveStartTLI;
1455 20 : flushed_lsn = WalRcv->flushedUpto;
1456 20 : received_tli = WalRcv->receivedTLI;
1457 20 : last_send_time = WalRcv->lastMsgSendTime;
1458 20 : last_receipt_time = WalRcv->lastMsgReceiptTime;
1459 20 : latest_end_lsn = WalRcv->latestWalEnd;
1460 20 : latest_end_time = WalRcv->latestWalEndTime;
1461 20 : strlcpy(slotname, WalRcv->slotname, sizeof(slotname));
1462 20 : strlcpy(sender_host, WalRcv->sender_host, sizeof(sender_host));
1463 20 : sender_port = WalRcv->sender_port;
1464 20 : strlcpy(conninfo, WalRcv->conninfo, sizeof(conninfo));
1465 20 : SpinLockRelease(&WalRcv->mutex);
1466 :
1467 : /*
1468 : * No WAL receiver (or not ready yet), just return a tuple with NULL
1469 : * values
1470 : */
1471 20 : if (pid == 0 || !ready_to_display)
1472 9 : PG_RETURN_NULL();
1473 :
1474 : /*
1475 : * Read "writtenUpto" without holding a spinlock. Note that it may not be
1476 : * consistent with the other shared variables of the WAL receiver
1477 : * protected by a spinlock, but this should not be used for data integrity
1478 : * checks.
1479 : */
1480 11 : written_lsn = pg_atomic_read_u64(&WalRcv->writtenUpto);
1481 :
1482 : /* determine result type */
1483 11 : if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
1484 0 : elog(ERROR, "return type must be a row type");
1485 :
1486 11 : values = palloc0_array(Datum, tupdesc->natts);
1487 11 : nulls = palloc0_array(bool, tupdesc->natts);
1488 :
1489 : /* Fetch values */
1490 11 : values[0] = Int32GetDatum(pid);
1491 :
1492 11 : if (!has_privs_of_role(GetUserId(), ROLE_PG_READ_ALL_STATS))
1493 : {
1494 : /*
1495 : * Only superusers and roles with privileges of pg_read_all_stats can
1496 : * see details. Other users only get the pid value to know whether it
1497 : * is a WAL receiver, but no details.
1498 : */
1499 0 : memset(&nulls[1], true, sizeof(bool) * (tupdesc->natts - 1));
1500 : }
1501 : else
1502 : {
1503 11 : values[1] = CStringGetTextDatum(WalRcvGetStateString(state));
1504 :
1505 11 : if (!XLogRecPtrIsValid(receive_start_lsn))
1506 0 : nulls[2] = true;
1507 : else
1508 11 : values[2] = LSNGetDatum(receive_start_lsn);
1509 11 : values[3] = Int32GetDatum(receive_start_tli);
1510 11 : if (!XLogRecPtrIsValid(written_lsn))
1511 0 : nulls[4] = true;
1512 : else
1513 11 : values[4] = LSNGetDatum(written_lsn);
1514 11 : if (!XLogRecPtrIsValid(flushed_lsn))
1515 0 : nulls[5] = true;
1516 : else
1517 11 : values[5] = LSNGetDatum(flushed_lsn);
1518 11 : values[6] = Int32GetDatum(received_tli);
1519 11 : if (last_send_time == 0)
1520 0 : nulls[7] = true;
1521 : else
1522 11 : values[7] = TimestampTzGetDatum(last_send_time);
1523 11 : if (last_receipt_time == 0)
1524 0 : nulls[8] = true;
1525 : else
1526 11 : values[8] = TimestampTzGetDatum(last_receipt_time);
1527 11 : if (!XLogRecPtrIsValid(latest_end_lsn))
1528 0 : nulls[9] = true;
1529 : else
1530 11 : values[9] = LSNGetDatum(latest_end_lsn);
1531 11 : if (latest_end_time == 0)
1532 0 : nulls[10] = true;
1533 : else
1534 11 : values[10] = TimestampTzGetDatum(latest_end_time);
1535 11 : if (*slotname == '\0')
1536 11 : nulls[11] = true;
1537 : else
1538 0 : values[11] = CStringGetTextDatum(slotname);
1539 11 : if (*sender_host == '\0')
1540 0 : nulls[12] = true;
1541 : else
1542 11 : values[12] = CStringGetTextDatum(sender_host);
1543 11 : if (sender_port == 0)
1544 0 : nulls[13] = true;
1545 : else
1546 11 : values[13] = Int32GetDatum(sender_port);
1547 11 : if (*conninfo == '\0')
1548 0 : nulls[14] = true;
1549 : else
1550 11 : values[14] = CStringGetTextDatum(conninfo);
1551 : }
1552 :
1553 : /* Returns the record as Datum */
1554 11 : PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
1555 : }
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