Line data Source code
1 : /*-------------------------------------------------------------------------
2 : * sequencesync.c
3 : * PostgreSQL logical replication: sequence synchronization
4 : *
5 : * Copyright (c) 2025, PostgreSQL Global Development Group
6 : *
7 : * IDENTIFICATION
8 : * src/backend/replication/logical/sequencesync.c
9 : *
10 : * NOTES
11 : * This file contains code for sequence synchronization for
12 : * logical replication.
13 : *
14 : * Sequences requiring synchronization are tracked in the pg_subscription_rel
15 : * catalog.
16 : *
17 : * Sequences to be synchronized will be added with state INIT when either of
18 : * the following commands is executed:
19 : * CREATE SUBSCRIPTION
20 : * ALTER SUBSCRIPTION ... REFRESH PUBLICATION
21 : *
22 : * Executing the following command resets all sequences in the subscription to
23 : * state INIT, triggering re-synchronization:
24 : * ALTER SUBSCRIPTION ... REFRESH SEQUENCES
25 : *
26 : * The apply worker periodically scans pg_subscription_rel for sequences in
27 : * INIT state. When such sequences are found, it spawns a sequencesync worker
28 : * to handle synchronization.
29 : *
30 : * A single sequencesync worker is responsible for synchronizing all sequences.
31 : * It begins by retrieving the list of sequences that are flagged for
32 : * synchronization, i.e., those in the INIT state. These sequences are then
33 : * processed in batches, allowing multiple entries to be synchronized within a
34 : * single transaction. The worker fetches the current sequence values and page
35 : * LSNs from the remote publisher, updates the corresponding sequences on the
36 : * local subscriber, and finally marks each sequence as READY upon successful
37 : * synchronization.
38 : *
39 : * Sequence state transitions follow this pattern:
40 : * INIT -> READY
41 : *
42 : * To avoid creating too many transactions, up to MAX_SEQUENCES_SYNC_PER_BATCH
43 : * sequences are synchronized per transaction. The locks on the sequence
44 : * relation will be periodically released at each transaction commit.
45 : *
46 : * XXX: We didn't choose launcher process to maintain the launch of sequencesync
47 : * worker as it didn't have database connection to access the sequences from the
48 : * pg_subscription_rel system catalog that need to be synchronized.
49 : *-------------------------------------------------------------------------
50 : */
51 :
52 : #include "postgres.h"
53 :
54 : #include "access/table.h"
55 : #include "catalog/pg_sequence.h"
56 : #include "catalog/pg_subscription_rel.h"
57 : #include "commands/sequence.h"
58 : #include "pgstat.h"
59 : #include "postmaster/interrupt.h"
60 : #include "replication/logicalworker.h"
61 : #include "replication/worker_internal.h"
62 : #include "utils/acl.h"
63 : #include "utils/builtins.h"
64 : #include "utils/fmgroids.h"
65 : #include "utils/guc.h"
66 : #include "utils/inval.h"
67 : #include "utils/lsyscache.h"
68 : #include "utils/memutils.h"
69 : #include "utils/pg_lsn.h"
70 : #include "utils/syscache.h"
71 : #include "utils/usercontext.h"
72 :
73 : #define REMOTE_SEQ_COL_COUNT 10
74 :
75 : typedef enum CopySeqResult
76 : {
77 : COPYSEQ_SUCCESS,
78 : COPYSEQ_MISMATCH,
79 : COPYSEQ_INSUFFICIENT_PERM,
80 : COPYSEQ_SKIPPED
81 : } CopySeqResult;
82 :
83 : static List *seqinfos = NIL;
84 :
85 : /*
86 : * Apply worker determines if sequence synchronization is needed.
87 : *
88 : * Start a sequencesync worker if one is not already running. The active
89 : * sequencesync worker will handle all pending sequence synchronization. If any
90 : * sequences remain unsynchronized after it exits, a new worker can be started
91 : * in the next iteration.
92 : */
93 : void
94 11976 : ProcessSequencesForSync(void)
95 : {
96 : LogicalRepWorker *sequencesync_worker;
97 : int nsyncworkers;
98 : bool has_pending_sequences;
99 : bool started_tx;
100 :
101 11976 : FetchRelationStates(NULL, &has_pending_sequences, &started_tx);
102 :
103 11976 : if (started_tx)
104 : {
105 356 : CommitTransactionCommand();
106 356 : pgstat_report_stat(true);
107 : }
108 :
109 11976 : if (!has_pending_sequences)
110 11944 : return;
111 :
112 56 : LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
113 :
114 : /* Check if there is a sequencesync worker already running? */
115 56 : sequencesync_worker = logicalrep_worker_find(WORKERTYPE_SEQUENCESYNC,
116 56 : MyLogicalRepWorker->subid,
117 : InvalidOid, true);
118 56 : if (sequencesync_worker)
119 : {
120 24 : LWLockRelease(LogicalRepWorkerLock);
121 24 : return;
122 : }
123 :
124 : /*
125 : * Count running sync workers for this subscription, while we have the
126 : * lock.
127 : */
128 32 : nsyncworkers = logicalrep_sync_worker_count(MyLogicalRepWorker->subid);
129 32 : LWLockRelease(LogicalRepWorkerLock);
130 :
131 : /*
132 : * It is okay to read/update last_seqsync_start_time here in apply worker
133 : * as we have already ensured that sync worker doesn't exist.
134 : */
135 32 : launch_sync_worker(WORKERTYPE_SEQUENCESYNC, nsyncworkers, InvalidOid,
136 32 : &MyLogicalRepWorker->last_seqsync_start_time);
137 : }
138 :
139 : /*
140 : * get_sequences_string
141 : *
142 : * Build a comma-separated string of schema-qualified sequence names
143 : * for the given list of sequence indexes.
144 : */
145 : static void
146 8 : get_sequences_string(List *seqindexes, StringInfo buf)
147 : {
148 8 : resetStringInfo(buf);
149 24 : foreach_int(seqidx, seqindexes)
150 : {
151 : LogicalRepSequenceInfo *seqinfo =
152 8 : (LogicalRepSequenceInfo *) list_nth(seqinfos, seqidx);
153 :
154 8 : if (buf->len > 0)
155 0 : appendStringInfoString(buf, ", ");
156 :
157 8 : appendStringInfo(buf, "\"%s.%s\"", seqinfo->nspname, seqinfo->seqname);
158 : }
159 8 : }
160 :
161 : /*
162 : * report_sequence_errors
163 : *
164 : * Report discrepancies found during sequence synchronization between
165 : * the publisher and subscriber. Emits warnings for:
166 : * a) mismatched definitions or concurrent rename
167 : * b) insufficient privileges
168 : * c) missing sequences on the subscriber
169 : * Then raises an ERROR to indicate synchronization failure.
170 : */
171 : static void
172 18 : report_sequence_errors(List *mismatched_seqs_idx, List *insuffperm_seqs_idx,
173 : List *missing_seqs_idx)
174 : {
175 : StringInfo seqstr;
176 :
177 : /* Quick exit if there are no errors to report */
178 18 : if (!mismatched_seqs_idx && !insuffperm_seqs_idx && !missing_seqs_idx)
179 10 : return;
180 :
181 8 : seqstr = makeStringInfo();
182 :
183 8 : if (mismatched_seqs_idx)
184 : {
185 6 : get_sequences_string(mismatched_seqs_idx, seqstr);
186 6 : ereport(WARNING,
187 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
188 : errmsg_plural("mismatched or renamed sequence on subscriber (%s)",
189 : "mismatched or renamed sequences on subscriber (%s)",
190 : list_length(mismatched_seqs_idx),
191 : seqstr->data));
192 : }
193 :
194 8 : if (insuffperm_seqs_idx)
195 : {
196 0 : get_sequences_string(insuffperm_seqs_idx, seqstr);
197 0 : ereport(WARNING,
198 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
199 : errmsg_plural("insufficient privileges on sequence (%s)",
200 : "insufficient privileges on sequences (%s)",
201 : list_length(insuffperm_seqs_idx),
202 : seqstr->data));
203 : }
204 :
205 8 : if (missing_seqs_idx)
206 : {
207 2 : get_sequences_string(missing_seqs_idx, seqstr);
208 2 : ereport(WARNING,
209 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
210 : errmsg_plural("missing sequence on publisher (%s)",
211 : "missing sequences on publisher (%s)",
212 : list_length(missing_seqs_idx),
213 : seqstr->data));
214 : }
215 :
216 8 : ereport(ERROR,
217 : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
218 : errmsg("logical replication sequence synchronization failed for subscription \"%s\"",
219 : MySubscription->name));
220 : }
221 :
222 : /*
223 : * get_and_validate_seq_info
224 : *
225 : * Extracts remote sequence information from the tuple slot received from the
226 : * publisher, and validates it against the corresponding local sequence
227 : * definition.
228 : */
229 : static CopySeqResult
230 24 : get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel,
231 : LogicalRepSequenceInfo **seqinfo, int *seqidx)
232 : {
233 : bool isnull;
234 24 : int col = 0;
235 : Oid remote_typid;
236 : int64 remote_start;
237 : int64 remote_increment;
238 : int64 remote_min;
239 : int64 remote_max;
240 : bool remote_cycle;
241 24 : CopySeqResult result = COPYSEQ_SUCCESS;
242 : HeapTuple tup;
243 : Form_pg_sequence local_seq;
244 : LogicalRepSequenceInfo *seqinfo_local;
245 :
246 24 : *seqidx = DatumGetInt32(slot_getattr(slot, ++col, &isnull));
247 : Assert(!isnull);
248 :
249 : /* Identify the corresponding local sequence for the given index. */
250 24 : *seqinfo = seqinfo_local =
251 24 : (LogicalRepSequenceInfo *) list_nth(seqinfos, *seqidx);
252 :
253 24 : seqinfo_local->last_value = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
254 : Assert(!isnull);
255 :
256 24 : seqinfo_local->is_called = DatumGetBool(slot_getattr(slot, ++col, &isnull));
257 : Assert(!isnull);
258 :
259 24 : seqinfo_local->page_lsn = DatumGetLSN(slot_getattr(slot, ++col, &isnull));
260 : Assert(!isnull);
261 :
262 24 : remote_typid = DatumGetObjectId(slot_getattr(slot, ++col, &isnull));
263 : Assert(!isnull);
264 :
265 24 : remote_start = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
266 : Assert(!isnull);
267 :
268 24 : remote_increment = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
269 : Assert(!isnull);
270 :
271 24 : remote_min = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
272 : Assert(!isnull);
273 :
274 24 : remote_max = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
275 : Assert(!isnull);
276 :
277 24 : remote_cycle = DatumGetBool(slot_getattr(slot, ++col, &isnull));
278 : Assert(!isnull);
279 :
280 : /* Sanity check */
281 : Assert(col == REMOTE_SEQ_COL_COUNT);
282 :
283 24 : seqinfo_local->found_on_pub = true;
284 :
285 24 : *sequence_rel = try_table_open(seqinfo_local->localrelid, RowExclusiveLock);
286 :
287 : /* Sequence was concurrently dropped? */
288 24 : if (!*sequence_rel)
289 0 : return COPYSEQ_SKIPPED;
290 :
291 24 : tup = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqinfo_local->localrelid));
292 :
293 : /* Sequence was concurrently dropped? */
294 24 : if (!HeapTupleIsValid(tup))
295 0 : elog(ERROR, "cache lookup failed for sequence %u",
296 : seqinfo_local->localrelid);
297 :
298 24 : local_seq = (Form_pg_sequence) GETSTRUCT(tup);
299 :
300 : /* Sequence parameters for remote/local are the same? */
301 24 : if (local_seq->seqtypid != remote_typid ||
302 24 : local_seq->seqstart != remote_start ||
303 22 : local_seq->seqincrement != remote_increment ||
304 18 : local_seq->seqmin != remote_min ||
305 18 : local_seq->seqmax != remote_max ||
306 18 : local_seq->seqcycle != remote_cycle)
307 6 : result = COPYSEQ_MISMATCH;
308 :
309 : /* Sequence was concurrently renamed? */
310 24 : if (strcmp(seqinfo_local->nspname,
311 24 : get_namespace_name(RelationGetNamespace(*sequence_rel))) ||
312 24 : strcmp(seqinfo_local->seqname, RelationGetRelationName(*sequence_rel)))
313 0 : result = COPYSEQ_MISMATCH;
314 :
315 24 : ReleaseSysCache(tup);
316 24 : return result;
317 : }
318 :
319 : /*
320 : * Apply remote sequence state to local sequence and mark it as
321 : * synchronized (READY).
322 : */
323 : static CopySeqResult
324 18 : copy_sequence(LogicalRepSequenceInfo *seqinfo, Oid seqowner)
325 : {
326 : UserContext ucxt;
327 : AclResult aclresult;
328 18 : bool run_as_owner = MySubscription->runasowner;
329 18 : Oid seqoid = seqinfo->localrelid;
330 :
331 : /*
332 : * If the user did not opt to run as the owner of the subscription
333 : * ('run_as_owner'), then copy the sequence as the owner of the sequence.
334 : */
335 18 : if (!run_as_owner)
336 18 : SwitchToUntrustedUser(seqowner, &ucxt);
337 :
338 18 : aclresult = pg_class_aclcheck(seqoid, GetUserId(), ACL_UPDATE);
339 :
340 18 : if (aclresult != ACLCHECK_OK)
341 : {
342 0 : if (!run_as_owner)
343 0 : RestoreUserContext(&ucxt);
344 :
345 0 : return COPYSEQ_INSUFFICIENT_PERM;
346 : }
347 :
348 : /*
349 : * The log counter (log_cnt) tracks how many sequence values are still
350 : * unused locally. It is only relevant to the local node and managed
351 : * internally by nextval() when allocating new ranges. Since log_cnt does
352 : * not affect the visible sequence state (like last_value or is_called)
353 : * and is only used for local caching, it need not be copied to the
354 : * subscriber during synchronization.
355 : */
356 18 : SetSequence(seqoid, seqinfo->last_value, seqinfo->is_called);
357 :
358 18 : if (!run_as_owner)
359 18 : RestoreUserContext(&ucxt);
360 :
361 : /*
362 : * Record the remote sequence's LSN in pg_subscription_rel and mark the
363 : * sequence as READY.
364 : */
365 18 : UpdateSubscriptionRelState(MySubscription->oid, seqoid, SUBREL_STATE_READY,
366 : seqinfo->page_lsn, false);
367 :
368 18 : return COPYSEQ_SUCCESS;
369 : }
370 :
371 : /*
372 : * Copy existing data of sequences from the publisher.
373 : */
374 : static void
375 18 : copy_sequences(WalReceiverConn *conn)
376 : {
377 18 : int cur_batch_base_index = 0;
378 18 : int n_seqinfos = list_length(seqinfos);
379 18 : List *mismatched_seqs_idx = NIL;
380 18 : List *missing_seqs_idx = NIL;
381 18 : List *insuffperm_seqs_idx = NIL;
382 18 : StringInfo seqstr = makeStringInfo();
383 18 : StringInfo cmd = makeStringInfo();
384 : MemoryContext oldctx;
385 :
386 : #define MAX_SEQUENCES_SYNC_PER_BATCH 100
387 :
388 18 : elog(DEBUG1,
389 : "logical replication sequence synchronization for subscription \"%s\" - total unsynchronized: %d",
390 : MySubscription->name, n_seqinfos);
391 :
392 36 : while (cur_batch_base_index < n_seqinfos)
393 : {
394 18 : Oid seqRow[REMOTE_SEQ_COL_COUNT] = {INT8OID, INT8OID,
395 : BOOLOID, LSNOID, OIDOID, INT8OID, INT8OID, INT8OID, INT8OID, BOOLOID};
396 18 : int batch_size = 0;
397 18 : int batch_succeeded_count = 0;
398 18 : int batch_mismatched_count = 0;
399 18 : int batch_skipped_count = 0;
400 18 : int batch_insuffperm_count = 0;
401 : int batch_missing_count;
402 : Relation sequence_rel;
403 :
404 : WalRcvExecResult *res;
405 : TupleTableSlot *slot;
406 :
407 18 : StartTransactionCommand();
408 :
409 44 : for (int idx = cur_batch_base_index; idx < n_seqinfos; idx++)
410 : {
411 : char *nspname_literal;
412 : char *seqname_literal;
413 :
414 : LogicalRepSequenceInfo *seqinfo =
415 26 : (LogicalRepSequenceInfo *) list_nth(seqinfos, idx);
416 :
417 26 : if (seqstr->len > 0)
418 8 : appendStringInfoString(seqstr, ", ");
419 :
420 26 : nspname_literal = quote_literal_cstr(seqinfo->nspname);
421 26 : seqname_literal = quote_literal_cstr(seqinfo->seqname);
422 :
423 26 : appendStringInfo(seqstr, "(%s, %s, %d)",
424 : nspname_literal, seqname_literal, idx);
425 :
426 26 : if (++batch_size == MAX_SEQUENCES_SYNC_PER_BATCH)
427 0 : break;
428 : }
429 :
430 : /*
431 : * We deliberately avoid acquiring a local lock on the sequence before
432 : * querying the publisher to prevent potential distributed deadlocks
433 : * in bi-directional replication setups.
434 : *
435 : * Example scenario:
436 : *
437 : * - On each node, a background worker acquires a lock on a sequence
438 : * as part of a sync operation.
439 : *
440 : * - Concurrently, a user transaction attempts to alter the same
441 : * sequence, waiting on the background worker's lock.
442 : *
443 : * - Meanwhile, a query from the other node tries to access metadata
444 : * that depends on the completion of the alter operation.
445 : *
446 : * - This creates a circular wait across nodes:
447 : *
448 : * Node-1: Query -> waits on Alter -> waits on Sync Worker
449 : *
450 : * Node-2: Query -> waits on Alter -> waits on Sync Worker
451 : *
452 : * Since each node only sees part of the wait graph, the deadlock may
453 : * go undetected, leading to indefinite blocking.
454 : *
455 : * Note: Each entry in VALUES includes an index 'seqidx' that
456 : * represents the sequence's position in the local 'seqinfos' list.
457 : * This index is propagated to the query results and later used to
458 : * directly map the fetched publisher sequence rows back to their
459 : * corresponding local entries without relying on result order or name
460 : * matching.
461 : */
462 18 : appendStringInfo(cmd,
463 : "SELECT s.seqidx, ps.*, seq.seqtypid,\n"
464 : " seq.seqstart, seq.seqincrement, seq.seqmin,\n"
465 : " seq.seqmax, seq.seqcycle\n"
466 : "FROM ( VALUES %s ) AS s (schname, seqname, seqidx)\n"
467 : "JOIN pg_namespace n ON n.nspname = s.schname\n"
468 : "JOIN pg_class c ON c.relnamespace = n.oid AND c.relname = s.seqname\n"
469 : "JOIN pg_sequence seq ON seq.seqrelid = c.oid\n"
470 : "JOIN LATERAL pg_get_sequence_data(seq.seqrelid) AS ps ON true\n",
471 : seqstr->data);
472 :
473 18 : res = walrcv_exec(conn, cmd->data, lengthof(seqRow), seqRow);
474 18 : if (res->status != WALRCV_OK_TUPLES)
475 0 : ereport(ERROR,
476 : errcode(ERRCODE_CONNECTION_FAILURE),
477 : errmsg("could not fetch sequence information from the publisher: %s",
478 : res->err));
479 :
480 18 : slot = MakeSingleTupleTableSlot(res->tupledesc, &TTSOpsMinimalTuple);
481 42 : while (tuplestore_gettupleslot(res->tuplestore, true, false, slot))
482 : {
483 : CopySeqResult sync_status;
484 : LogicalRepSequenceInfo *seqinfo;
485 : int seqidx;
486 :
487 24 : CHECK_FOR_INTERRUPTS();
488 :
489 24 : if (ConfigReloadPending)
490 : {
491 0 : ConfigReloadPending = false;
492 0 : ProcessConfigFile(PGC_SIGHUP);
493 : }
494 :
495 24 : sync_status = get_and_validate_seq_info(slot, &sequence_rel,
496 : &seqinfo, &seqidx);
497 24 : if (sync_status == COPYSEQ_SUCCESS)
498 18 : sync_status = copy_sequence(seqinfo,
499 18 : sequence_rel->rd_rel->relowner);
500 :
501 24 : switch (sync_status)
502 : {
503 18 : case COPYSEQ_SUCCESS:
504 18 : elog(DEBUG1,
505 : "logical replication synchronization for subscription \"%s\", sequence \"%s.%s\" has finished",
506 : MySubscription->name, seqinfo->nspname,
507 : seqinfo->seqname);
508 18 : batch_succeeded_count++;
509 18 : break;
510 6 : case COPYSEQ_MISMATCH:
511 :
512 : /*
513 : * Remember mismatched sequences in a long-lived memory
514 : * context since these will be used after the transaction
515 : * is committed.
516 : */
517 6 : oldctx = MemoryContextSwitchTo(ApplyContext);
518 6 : mismatched_seqs_idx = lappend_int(mismatched_seqs_idx,
519 : seqidx);
520 6 : MemoryContextSwitchTo(oldctx);
521 6 : batch_mismatched_count++;
522 6 : break;
523 0 : case COPYSEQ_INSUFFICIENT_PERM:
524 :
525 : /*
526 : * Remember sequences with insufficient privileges in a
527 : * long-lived memory context since these will be used
528 : * after the transaction is committed.
529 : */
530 0 : oldctx = MemoryContextSwitchTo(ApplyContext);
531 0 : insuffperm_seqs_idx = lappend_int(insuffperm_seqs_idx,
532 : seqidx);
533 0 : MemoryContextSwitchTo(oldctx);
534 0 : batch_insuffperm_count++;
535 0 : break;
536 0 : case COPYSEQ_SKIPPED:
537 0 : ereport(LOG,
538 : errmsg("skip synchronization of sequence \"%s.%s\" because it has been dropped concurrently",
539 : seqinfo->nspname,
540 : seqinfo->seqname));
541 0 : batch_skipped_count++;
542 0 : break;
543 : }
544 :
545 24 : if (sequence_rel)
546 24 : table_close(sequence_rel, NoLock);
547 : }
548 :
549 18 : ExecDropSingleTupleTableSlot(slot);
550 18 : walrcv_clear_result(res);
551 18 : resetStringInfo(seqstr);
552 18 : resetStringInfo(cmd);
553 :
554 18 : batch_missing_count = batch_size - (batch_succeeded_count +
555 18 : batch_mismatched_count +
556 18 : batch_insuffperm_count +
557 : batch_skipped_count);
558 :
559 18 : elog(DEBUG1,
560 : "logical replication sequence synchronization for subscription \"%s\" - batch #%d = %d attempted, %d succeeded, %d mismatched, %d insufficient permission, %d missing from publisher, %d skipped",
561 : MySubscription->name,
562 : (cur_batch_base_index / MAX_SEQUENCES_SYNC_PER_BATCH) + 1,
563 : batch_size, batch_succeeded_count, batch_mismatched_count,
564 : batch_insuffperm_count, batch_missing_count, batch_skipped_count);
565 :
566 : /* Commit this batch, and prepare for next batch */
567 18 : CommitTransactionCommand();
568 :
569 18 : if (batch_missing_count)
570 : {
571 4 : for (int idx = cur_batch_base_index; idx < cur_batch_base_index + batch_size; idx++)
572 : {
573 : LogicalRepSequenceInfo *seqinfo =
574 2 : (LogicalRepSequenceInfo *) list_nth(seqinfos, idx);
575 :
576 : /* If the sequence was not found on publisher, record it */
577 2 : if (!seqinfo->found_on_pub)
578 2 : missing_seqs_idx = lappend_int(missing_seqs_idx, idx);
579 : }
580 : }
581 :
582 : /*
583 : * cur_batch_base_index is not incremented sequentially because some
584 : * sequences may be missing, and the number of fetched rows may not
585 : * match the batch size.
586 : */
587 18 : cur_batch_base_index += batch_size;
588 : }
589 :
590 : /* Report mismatches, permission issues, or missing sequences */
591 18 : report_sequence_errors(mismatched_seqs_idx, insuffperm_seqs_idx,
592 : missing_seqs_idx);
593 10 : }
594 :
595 : /*
596 : * Identifies sequences that require synchronization and initiates the
597 : * synchronization process.
598 : */
599 : static void
600 18 : LogicalRepSyncSequences(void)
601 : {
602 : char *err;
603 : bool must_use_password;
604 : Relation rel;
605 : HeapTuple tup;
606 : ScanKeyData skey[2];
607 : SysScanDesc scan;
608 18 : Oid subid = MyLogicalRepWorker->subid;
609 : StringInfoData app_name;
610 :
611 18 : StartTransactionCommand();
612 :
613 18 : rel = table_open(SubscriptionRelRelationId, AccessShareLock);
614 :
615 18 : ScanKeyInit(&skey[0],
616 : Anum_pg_subscription_rel_srsubid,
617 : BTEqualStrategyNumber, F_OIDEQ,
618 : ObjectIdGetDatum(subid));
619 :
620 18 : ScanKeyInit(&skey[1],
621 : Anum_pg_subscription_rel_srsubstate,
622 : BTEqualStrategyNumber, F_CHAREQ,
623 : CharGetDatum(SUBREL_STATE_INIT));
624 :
625 18 : scan = systable_beginscan(rel, InvalidOid, false,
626 : NULL, 2, skey);
627 48 : while (HeapTupleIsValid(tup = systable_getnext(scan)))
628 : {
629 : Form_pg_subscription_rel subrel;
630 : LogicalRepSequenceInfo *seq;
631 : Relation sequence_rel;
632 : MemoryContext oldctx;
633 :
634 30 : CHECK_FOR_INTERRUPTS();
635 :
636 30 : subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
637 :
638 30 : sequence_rel = try_table_open(subrel->srrelid, RowExclusiveLock);
639 :
640 : /* Skip if sequence was dropped concurrently */
641 30 : if (!sequence_rel)
642 0 : continue;
643 :
644 : /* Skip if the relation is not a sequence */
645 30 : if (sequence_rel->rd_rel->relkind != RELKIND_SEQUENCE)
646 : {
647 4 : table_close(sequence_rel, NoLock);
648 4 : continue;
649 : }
650 :
651 : /*
652 : * Worker needs to process sequences across transaction boundary, so
653 : * allocate them under long-lived context.
654 : */
655 26 : oldctx = MemoryContextSwitchTo(ApplyContext);
656 :
657 26 : seq = palloc0_object(LogicalRepSequenceInfo);
658 26 : seq->localrelid = subrel->srrelid;
659 26 : seq->nspname = get_namespace_name(RelationGetNamespace(sequence_rel));
660 26 : seq->seqname = pstrdup(RelationGetRelationName(sequence_rel));
661 26 : seqinfos = lappend(seqinfos, seq);
662 :
663 26 : MemoryContextSwitchTo(oldctx);
664 :
665 26 : table_close(sequence_rel, NoLock);
666 : }
667 :
668 : /* Cleanup */
669 18 : systable_endscan(scan);
670 18 : table_close(rel, AccessShareLock);
671 :
672 18 : CommitTransactionCommand();
673 :
674 : /*
675 : * Exit early if no catalog entries found, likely due to concurrent drops.
676 : */
677 18 : if (!seqinfos)
678 0 : return;
679 :
680 : /* Is the use of a password mandatory? */
681 36 : must_use_password = MySubscription->passwordrequired &&
682 18 : !MySubscription->ownersuperuser;
683 :
684 18 : initStringInfo(&app_name);
685 18 : appendStringInfo(&app_name, "pg_%u_sequence_sync_" UINT64_FORMAT,
686 18 : MySubscription->oid, GetSystemIdentifier());
687 :
688 : /*
689 : * Establish the connection to the publisher for sequence synchronization.
690 : */
691 18 : LogRepWorkerWalRcvConn =
692 18 : walrcv_connect(MySubscription->conninfo, true, true,
693 : must_use_password,
694 : app_name.data, &err);
695 18 : if (LogRepWorkerWalRcvConn == NULL)
696 0 : ereport(ERROR,
697 : errcode(ERRCODE_CONNECTION_FAILURE),
698 : errmsg("sequencesync worker for subscription \"%s\" could not connect to the publisher: %s",
699 : MySubscription->name, err));
700 :
701 18 : pfree(app_name.data);
702 :
703 18 : copy_sequences(LogRepWorkerWalRcvConn);
704 : }
705 :
706 : /*
707 : * Execute the initial sync with error handling. Disable the subscription,
708 : * if required.
709 : *
710 : * Note that we don't handle FATAL errors which are probably because of system
711 : * resource error and are not repeatable.
712 : */
713 : static void
714 18 : start_sequence_sync()
715 : {
716 : Assert(am_sequencesync_worker());
717 :
718 18 : PG_TRY();
719 : {
720 : /* Call initial sync. */
721 18 : LogicalRepSyncSequences();
722 : }
723 8 : PG_CATCH();
724 : {
725 8 : if (MySubscription->disableonerr)
726 0 : DisableSubscriptionAndExit();
727 : else
728 : {
729 : /*
730 : * Report the worker failed during sequence synchronization. Abort
731 : * the current transaction so that the stats message is sent in an
732 : * idle state.
733 : */
734 8 : AbortOutOfAnyTransaction();
735 8 : pgstat_report_subscription_error(MySubscription->oid,
736 : WORKERTYPE_SEQUENCESYNC);
737 :
738 8 : PG_RE_THROW();
739 : }
740 : }
741 10 : PG_END_TRY();
742 10 : }
743 :
744 : /* Logical Replication sequencesync worker entry point */
745 : void
746 18 : SequenceSyncWorkerMain(Datum main_arg)
747 : {
748 18 : int worker_slot = DatumGetInt32(main_arg);
749 :
750 18 : SetupApplyOrSyncWorker(worker_slot);
751 :
752 18 : start_sequence_sync();
753 :
754 10 : FinishSyncWorker();
755 : }
|
