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1 : : /*-------------------------------------------------------------------------
2 : : * sequencesync.c
3 : : * PostgreSQL logical replication: sequence synchronization
4 : : *
5 : : * Copyright (c) 2025-2026, 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/genam.h"
55 : : #include "access/table.h"
56 : : #include "catalog/pg_sequence.h"
57 : : #include "catalog/pg_subscription_rel.h"
58 : : #include "commands/sequence.h"
59 : : #include "pgstat.h"
60 : : #include "postmaster/interrupt.h"
61 : : #include "replication/logicalworker.h"
62 : : #include "replication/worker_internal.h"
63 : : #include "storage/lwlock.h"
64 : : #include "utils/acl.h"
65 : : #include "utils/builtins.h"
66 : : #include "utils/fmgroids.h"
67 : : #include "utils/guc.h"
68 : : #include "utils/inval.h"
69 : : #include "utils/lsyscache.h"
70 : : #include "utils/memutils.h"
71 : : #include "utils/pg_lsn.h"
72 : : #include "utils/syscache.h"
73 : : #include "utils/usercontext.h"
74 : :
75 : : #define REMOTE_SEQ_COL_COUNT 11
76 : :
77 : : typedef enum CopySeqResult
78 : : {
79 : : COPYSEQ_SUCCESS,
80 : : COPYSEQ_MISMATCH,
81 : : COPYSEQ_SUBSCRIBER_INSUFFICIENT_PERM,
82 : : COPYSEQ_PUBLISHER_INSUFFICIENT_PERM,
83 : : COPYSEQ_SKIPPED
84 : : } CopySeqResult;
85 : :
86 : : static List *seqinfos = NIL;
87 : :
88 : : /*
89 : : * Apply worker determines if sequence synchronization is needed.
90 : : *
91 : : * Start a sequencesync worker if one is not already running. The active
92 : : * sequencesync worker will handle all pending sequence synchronization. If any
93 : : * sequences remain unsynchronized after it exits, a new worker can be started
94 : : * in the next iteration.
95 : : */
96 : : void
97 : 9877 : ProcessSequencesForSync(void)
98 : : {
99 : : LogicalRepWorker *sequencesync_worker;
100 : : int nsyncworkers;
101 : : bool has_pending_sequences;
102 : : bool started_tx;
103 : :
104 : 9877 : FetchRelationStates(NULL, &has_pending_sequences, &started_tx);
105 : :
106 [ + + ]: 9877 : if (started_tx)
107 : : {
108 : 190 : CommitTransactionCommand();
109 : 190 : pgstat_report_stat(true);
110 : : }
111 : :
112 [ + + ]: 9877 : if (!has_pending_sequences)
113 : 9851 : return;
114 : :
115 : 44 : LWLockAcquire(LogicalRepWorkerLock, LW_SHARED);
116 : :
117 : : /* Check if there is a sequencesync worker already running? */
118 : 44 : sequencesync_worker = logicalrep_worker_find(WORKERTYPE_SEQUENCESYNC,
119 : 44 : MyLogicalRepWorker->subid,
120 : : InvalidOid, true);
121 [ + + ]: 44 : if (sequencesync_worker)
122 : : {
123 : 18 : LWLockRelease(LogicalRepWorkerLock);
124 : 18 : return;
125 : : }
126 : :
127 : : /*
128 : : * Count running sync workers for this subscription, while we have the
129 : : * lock.
130 : : */
131 : 26 : nsyncworkers = logicalrep_sync_worker_count(MyLogicalRepWorker->subid);
132 : 26 : LWLockRelease(LogicalRepWorkerLock);
133 : :
134 : : /*
135 : : * It is okay to read/update last_seqsync_start_time here in apply worker
136 : : * as we have already ensured that sync worker doesn't exist.
137 : : */
138 : 26 : launch_sync_worker(WORKERTYPE_SEQUENCESYNC, nsyncworkers, InvalidOid,
139 : 26 : &MyLogicalRepWorker->last_seqsync_start_time);
140 : : }
141 : :
142 : : /*
143 : : * get_sequences_string
144 : : *
145 : : * Build a comma-separated string of schema-qualified sequence names
146 : : * for the given list of sequence indexes.
147 : : */
148 : : static void
149 : 7 : get_sequences_string(List *seqindexes, StringInfo buf)
150 : : {
151 : 7 : resetStringInfo(buf);
152 [ + - + + : 21 : foreach_int(seqidx, seqindexes)
+ + ]
153 : : {
154 : : LogicalRepSequenceInfo *seqinfo =
155 : 7 : (LogicalRepSequenceInfo *) list_nth(seqinfos, seqidx);
156 : :
157 [ - + ]: 7 : if (buf->len > 0)
158 : 0 : appendStringInfoString(buf, ", ");
159 : :
160 : 7 : appendStringInfo(buf, "\"%s.%s\"", seqinfo->nspname, seqinfo->seqname);
161 : : }
162 : 7 : }
163 : :
164 : : /*
165 : : * report_sequence_errors
166 : : *
167 : : * Report discrepancies found during sequence synchronization between
168 : : * the publisher and subscriber. Emits warnings for:
169 : : * a) mismatched definitions or concurrent rename
170 : : * b) insufficient privileges on the subscriber
171 : : * c) insufficient privileges on the publisher
172 : : * d) missing sequences on the publisher
173 : : * Then raises an ERROR to indicate synchronization failure.
174 : : */
175 : : static void
176 : 14 : report_sequence_errors(List *mismatched_seqs_idx,
177 : : List *sub_insuffperm_seqs_idx,
178 : : List *pub_insuffperm_seqs_idx,
179 : : List *missing_seqs_idx)
180 : : {
181 : : StringInfoData seqstr;
182 : :
183 : : /* Quick exit if there are no errors to report */
184 [ + + + - : 14 : if (!mismatched_seqs_idx && !sub_insuffperm_seqs_idx &&
+ + ]
185 [ + + ]: 10 : !pub_insuffperm_seqs_idx && !missing_seqs_idx)
186 : 7 : return;
187 : :
188 : 7 : initStringInfo(&seqstr);
189 : :
190 [ + + ]: 7 : if (mismatched_seqs_idx)
191 : : {
192 : 3 : get_sequences_string(mismatched_seqs_idx, &seqstr);
193 [ + - ]: 3 : ereport(WARNING,
194 : : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
195 : : errmsg_plural("mismatched or renamed sequence on subscriber (%s)",
196 : : "mismatched or renamed sequences on subscriber (%s)",
197 : : list_length(mismatched_seqs_idx),
198 : : seqstr.data));
199 : : }
200 : :
201 [ - + ]: 7 : if (sub_insuffperm_seqs_idx)
202 : : {
203 : 0 : get_sequences_string(sub_insuffperm_seqs_idx, &seqstr);
204 : :
205 : : /*
206 : : * With run_as_owner enabled, sequence synchronization runs as the
207 : : * subscription owner, so a missing UPDATE privilege should be granted
208 : : * to that role. Otherwise, the worker switches to the sequence owner
209 : : * before checking privileges, so no useful GRANT hint can be
210 : : * provided.
211 : : */
212 [ # # # # ]: 0 : ereport(WARNING,
213 : : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
214 : : errmsg_plural("insufficient privileges on subscriber sequence (%s)",
215 : : "insufficient privileges on subscriber sequences (%s)",
216 : : list_length(sub_insuffperm_seqs_idx),
217 : : seqstr.data),
218 : : MySubscription->runasowner ?
219 : : errhint_plural("Grant UPDATE on the sequence to the subscription "
220 : : "owner on the subscriber.",
221 : : "Grant UPDATE on the sequences to the subscription "
222 : : "owner on the subscriber.",
223 : : list_length(sub_insuffperm_seqs_idx)) : 0);
224 : : }
225 : :
226 [ + + ]: 7 : if (pub_insuffperm_seqs_idx)
227 : : {
228 : 1 : get_sequences_string(pub_insuffperm_seqs_idx, &seqstr);
229 [ + - ]: 1 : ereport(WARNING,
230 : : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
231 : : errmsg_plural("insufficient privileges on publisher sequence (%s)",
232 : : "insufficient privileges on publisher sequences (%s)",
233 : : list_length(pub_insuffperm_seqs_idx),
234 : : seqstr.data),
235 : : errhint_plural("Grant SELECT on the sequence to the role used for "
236 : : "the replication connection on the publisher.",
237 : : "Grant SELECT on the sequences to the role used for "
238 : : "the replication connection on the publisher.",
239 : : list_length(pub_insuffperm_seqs_idx)));
240 : : }
241 : :
242 [ + + ]: 7 : if (missing_seqs_idx)
243 : : {
244 : 3 : get_sequences_string(missing_seqs_idx, &seqstr);
245 [ + - ]: 3 : ereport(WARNING,
246 : : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
247 : : errmsg_plural("missing sequence on publisher (%s)",
248 : : "missing sequences on publisher (%s)",
249 : : list_length(missing_seqs_idx),
250 : : seqstr.data));
251 : : }
252 : :
253 [ + - ]: 7 : ereport(ERROR,
254 : : errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
255 : : errmsg("logical replication sequence synchronization failed for subscription \"%s\"",
256 : : MySubscription->name));
257 : : }
258 : :
259 : : /*
260 : : * get_and_validate_seq_info
261 : : *
262 : : * Extracts remote sequence information from the tuple slot received from the
263 : : * publisher, and validates it against the corresponding local sequence
264 : : * definition.
265 : : */
266 : : static CopySeqResult
267 : 27 : get_and_validate_seq_info(TupleTableSlot *slot, Relation *sequence_rel,
268 : : LogicalRepSequenceInfo **seqinfo, int *seqidx)
269 : : {
270 : : bool isnull;
271 : 27 : int col = 0;
272 : : Datum datum;
273 : : bool remote_has_select_priv;
274 : : Oid remote_typid;
275 : : int64 remote_start;
276 : : int64 remote_increment;
277 : : int64 remote_min;
278 : : int64 remote_max;
279 : : bool remote_cycle;
280 : 27 : CopySeqResult result = COPYSEQ_SUCCESS;
281 : : HeapTuple tup;
282 : : Form_pg_sequence local_seq;
283 : : LogicalRepSequenceInfo *seqinfo_local;
284 : :
285 : 27 : *seqidx = DatumGetInt32(slot_getattr(slot, ++col, &isnull));
286 : : Assert(!isnull);
287 : :
288 : : /* Identify the corresponding local sequence for the given index. */
289 : 27 : *seqinfo = seqinfo_local =
290 : 27 : (LogicalRepSequenceInfo *) list_nth(seqinfos, *seqidx);
291 : :
292 : : /*
293 : : * has_sequence_privilege() itself returns NULL, rather than false, when
294 : : * the sequence has been dropped concurrently after it was identified in
295 : : * the catalog snapshot (see has_sequence_privilege_id()). Treat that as a
296 : : * missing sequence on the publisher.
297 : : */
298 : 27 : datum = slot_getattr(slot, ++col, &isnull);
299 [ + + ]: 27 : if (isnull)
300 : 1 : return COPYSEQ_SKIPPED;
301 : :
302 : 26 : remote_has_select_priv = DatumGetBool(datum);
303 : :
304 : : /*
305 : : * The remote sequence state can be NULL if the publisher lacks the
306 : : * required privileges or if the sequence was dropped concurrently after
307 : : * it was identified in the catalog snapshot (see pg_get_sequence_data()).
308 : : */
309 : 26 : datum = slot_getattr(slot, ++col, &isnull);
310 [ + + ]: 26 : if (isnull)
311 [ - + ]: 1 : return remote_has_select_priv ? COPYSEQ_SKIPPED :
312 : : COPYSEQ_PUBLISHER_INSUFFICIENT_PERM;
313 : :
314 : 25 : seqinfo_local->last_value = DatumGetInt64(datum);
315 : :
316 : 25 : seqinfo_local->is_called = DatumGetBool(slot_getattr(slot, ++col, &isnull));
317 : : Assert(!isnull);
318 : :
319 : 25 : seqinfo_local->page_lsn = DatumGetLSN(slot_getattr(slot, ++col, &isnull));
320 : : Assert(!isnull);
321 : :
322 : 25 : remote_typid = DatumGetObjectId(slot_getattr(slot, ++col, &isnull));
323 : : Assert(!isnull);
324 : :
325 : 25 : remote_start = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
326 : : Assert(!isnull);
327 : :
328 : 25 : remote_increment = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
329 : : Assert(!isnull);
330 : :
331 : 25 : remote_min = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
332 : : Assert(!isnull);
333 : :
334 : 25 : remote_max = DatumGetInt64(slot_getattr(slot, ++col, &isnull));
335 : : Assert(!isnull);
336 : :
337 : 25 : remote_cycle = DatumGetBool(slot_getattr(slot, ++col, &isnull));
338 : : Assert(!isnull);
339 : :
340 : : /* Sanity check */
341 : : Assert(col == REMOTE_SEQ_COL_COUNT);
342 : :
343 : 25 : seqinfo_local->found_on_pub = true;
344 : :
345 : 25 : *sequence_rel = try_table_open(seqinfo_local->localrelid, RowExclusiveLock);
346 : :
347 : : /* Sequence was concurrently dropped? */
348 [ - + ]: 25 : if (!*sequence_rel)
349 : 0 : return COPYSEQ_SKIPPED;
350 : :
351 : 25 : tup = SearchSysCache1(SEQRELID, ObjectIdGetDatum(seqinfo_local->localrelid));
352 : :
353 : : /* Sequence was concurrently dropped? */
354 [ - + ]: 25 : if (!HeapTupleIsValid(tup))
355 [ # # ]: 0 : elog(ERROR, "cache lookup failed for sequence %u",
356 : : seqinfo_local->localrelid);
357 : :
358 : 25 : local_seq = (Form_pg_sequence) GETSTRUCT(tup);
359 : :
360 : : /* Sequence parameters for remote/local are the same? */
361 [ + - ]: 25 : if (local_seq->seqtypid != remote_typid ||
362 [ + + ]: 25 : local_seq->seqstart != remote_start ||
363 [ + + ]: 24 : local_seq->seqincrement != remote_increment ||
364 [ + - ]: 22 : local_seq->seqmin != remote_min ||
365 [ + - ]: 22 : local_seq->seqmax != remote_max ||
366 [ - + ]: 22 : local_seq->seqcycle != remote_cycle)
367 : 3 : result = COPYSEQ_MISMATCH;
368 : :
369 : : /* Sequence was concurrently renamed? */
370 [ + - ]: 25 : if (strcmp(seqinfo_local->nspname,
371 : 25 : get_namespace_name(RelationGetNamespace(*sequence_rel))) ||
372 [ - + ]: 25 : strcmp(seqinfo_local->seqname, RelationGetRelationName(*sequence_rel)))
373 : 0 : result = COPYSEQ_MISMATCH;
374 : :
375 : 25 : ReleaseSysCache(tup);
376 : 25 : return result;
377 : : }
378 : :
379 : : /*
380 : : * Apply remote sequence state to local sequence and mark it as
381 : : * synchronized (READY).
382 : : */
383 : : static CopySeqResult
384 : 22 : copy_sequence(LogicalRepSequenceInfo *seqinfo, Oid seqowner)
385 : : {
386 : : UserContext ucxt;
387 : : AclResult aclresult;
388 : 22 : bool run_as_owner = MySubscription->runasowner;
389 : 22 : Oid seqoid = seqinfo->localrelid;
390 : :
391 : : /*
392 : : * If the user did not opt to run as the owner of the subscription
393 : : * ('run_as_owner'), then copy the sequence as the owner of the sequence.
394 : : */
395 [ + - ]: 22 : if (!run_as_owner)
396 : 22 : SwitchToUntrustedUser(seqowner, &ucxt);
397 : :
398 : 22 : aclresult = pg_class_aclcheck(seqoid, GetUserId(), ACL_UPDATE);
399 : :
400 [ - + ]: 22 : if (aclresult != ACLCHECK_OK)
401 : : {
402 [ # # ]: 0 : if (!run_as_owner)
403 : 0 : RestoreUserContext(&ucxt);
404 : :
405 : 0 : return COPYSEQ_SUBSCRIBER_INSUFFICIENT_PERM;
406 : : }
407 : :
408 : : /*
409 : : * The log counter (log_cnt) tracks how many sequence values are still
410 : : * unused locally. It is only relevant to the local node and managed
411 : : * internally by nextval() when allocating new ranges. Since log_cnt does
412 : : * not affect the visible sequence state (like last_value or is_called)
413 : : * and is only used for local caching, it need not be copied to the
414 : : * subscriber during synchronization.
415 : : */
416 : 22 : SetSequence(seqoid, seqinfo->last_value, seqinfo->is_called);
417 : :
418 [ + - ]: 22 : if (!run_as_owner)
419 : 22 : RestoreUserContext(&ucxt);
420 : :
421 : : /*
422 : : * Record the remote sequence's LSN in pg_subscription_rel and mark the
423 : : * sequence as READY.
424 : : */
425 : 22 : UpdateSubscriptionRelState(MySubscription->oid, seqoid, SUBREL_STATE_READY,
426 : : seqinfo->page_lsn, false);
427 : :
428 : 22 : return COPYSEQ_SUCCESS;
429 : : }
430 : :
431 : : /*
432 : : * Copy existing data of sequences from the publisher.
433 : : */
434 : : static void
435 : 14 : copy_sequences(WalReceiverConn *conn)
436 : : {
437 : 14 : int cur_batch_base_index = 0;
438 : 14 : int n_seqinfos = list_length(seqinfos);
439 : 14 : List *mismatched_seqs_idx = NIL;
440 : 14 : List *missing_seqs_idx = NIL;
441 : 14 : List *sub_insuffperm_seqs_idx = NIL;
442 : 14 : List *pub_insuffperm_seqs_idx = NIL;
443 : : StringInfoData seqstr;
444 : : StringInfoData cmd;
445 : : MemoryContext oldctx;
446 : :
447 : 14 : initStringInfo(&seqstr);
448 : 14 : initStringInfo(&cmd);
449 : :
450 : : #define MAX_SEQUENCES_SYNC_PER_BATCH 100
451 : :
452 [ - + ]: 14 : elog(DEBUG1,
453 : : "logical replication sequence synchronization for subscription \"%s\" - total unsynchronized: %d",
454 : : MySubscription->name, n_seqinfos);
455 : :
456 [ + + ]: 28 : while (cur_batch_base_index < n_seqinfos)
457 : : {
458 : 14 : Oid seqRow[REMOTE_SEQ_COL_COUNT] = {INT8OID, BOOLOID, INT8OID,
459 : : BOOLOID, LSNOID, OIDOID, INT8OID, INT8OID, INT8OID, INT8OID, BOOLOID};
460 : 14 : int batch_size = 0;
461 : 14 : int batch_succeeded_count = 0;
462 : 14 : int batch_mismatched_count = 0;
463 : 14 : int batch_skipped_count = 0;
464 : 14 : int batch_sub_insuffperm_count = 0;
465 : 14 : int batch_pub_insuffperm_count = 0;
466 : : int batch_missing_count;
467 : :
468 : : WalRcvExecResult *res;
469 : : TupleTableSlot *slot;
470 : :
471 : 14 : StartTransactionCommand();
472 : :
473 [ + + ]: 43 : for (int idx = cur_batch_base_index; idx < n_seqinfos; idx++)
474 : : {
475 : : char *nspname_literal;
476 : : char *seqname_literal;
477 : :
478 : : LogicalRepSequenceInfo *seqinfo =
479 : 29 : (LogicalRepSequenceInfo *) list_nth(seqinfos, idx);
480 : :
481 [ + + ]: 29 : if (seqstr.len > 0)
482 : 15 : appendStringInfoString(&seqstr, ", ");
483 : :
484 : 29 : nspname_literal = quote_literal_cstr(seqinfo->nspname);
485 : 29 : seqname_literal = quote_literal_cstr(seqinfo->seqname);
486 : :
487 : 29 : appendStringInfo(&seqstr, "(%s, %s, %d)",
488 : : nspname_literal, seqname_literal, idx);
489 : :
490 [ - + ]: 29 : if (++batch_size == MAX_SEQUENCES_SYNC_PER_BATCH)
491 : 0 : break;
492 : : }
493 : :
494 : : /*
495 : : * We deliberately avoid acquiring a local lock on the sequence before
496 : : * querying the publisher to prevent potential distributed deadlocks
497 : : * in bi-directional replication setups.
498 : : *
499 : : * Example scenario:
500 : : *
501 : : * - On each node, a background worker acquires a lock on a sequence
502 : : * as part of a sync operation.
503 : : *
504 : : * - Concurrently, a user transaction attempts to alter the same
505 : : * sequence, waiting on the background worker's lock.
506 : : *
507 : : * - Meanwhile, a query from the other node tries to access metadata
508 : : * that depends on the completion of the alter operation.
509 : : *
510 : : * - This creates a circular wait across nodes:
511 : : *
512 : : * Node-1: Query -> waits on Alter -> waits on Sync Worker
513 : : *
514 : : * Node-2: Query -> waits on Alter -> waits on Sync Worker
515 : : *
516 : : * Since each node only sees part of the wait graph, the deadlock may
517 : : * go undetected, leading to indefinite blocking.
518 : : *
519 : : * Note: Each entry in VALUES includes an index 'seqidx' that
520 : : * represents the sequence's position in the local 'seqinfos' list.
521 : : * This index is propagated to the query results and later used to
522 : : * directly map the fetched publisher sequence rows back to their
523 : : * corresponding local entries without relying on result order or name
524 : : * matching.
525 : : */
526 : 14 : appendStringInfo(&cmd,
527 : : "SELECT s.seqidx, has_sequence_privilege(c.oid, 'SELECT'),\n"
528 : : " ps.*, seq.seqtypid,\n"
529 : : " seq.seqstart, seq.seqincrement, seq.seqmin,\n"
530 : : " seq.seqmax, seq.seqcycle\n"
531 : : "FROM ( VALUES %s ) AS s (schname, seqname, seqidx)\n"
532 : : "JOIN pg_namespace n ON n.nspname = s.schname\n"
533 : : "JOIN pg_class c ON c.relnamespace = n.oid AND c.relname = s.seqname\n"
534 : : "JOIN pg_sequence seq ON seq.seqrelid = c.oid\n"
535 : : "JOIN LATERAL pg_get_sequence_data(seq.seqrelid) AS ps ON true\n",
536 : : seqstr.data);
537 : :
538 : 14 : res = walrcv_exec(conn, cmd.data, lengthof(seqRow), seqRow);
539 [ - + ]: 14 : if (res->status != WALRCV_OK_TUPLES)
540 [ # # ]: 0 : ereport(ERROR,
541 : : errcode(ERRCODE_CONNECTION_FAILURE),
542 : : errmsg("could not fetch sequence information from the publisher: %s",
543 : : res->err));
544 : :
545 : 14 : slot = MakeSingleTupleTableSlot(res->tupledesc, &TTSOpsMinimalTuple);
546 [ + + ]: 41 : while (tuplestore_gettupleslot(res->tuplestore, true, false, slot))
547 : : {
548 : : CopySeqResult sync_status;
549 : : LogicalRepSequenceInfo *seqinfo;
550 : 27 : Relation sequence_rel = NULL;
551 : : int seqidx;
552 : :
553 [ - + ]: 27 : CHECK_FOR_INTERRUPTS();
554 : :
555 [ - + ]: 27 : if (ConfigReloadPending)
556 : : {
557 : 0 : ConfigReloadPending = false;
558 : 0 : ProcessConfigFile(PGC_SIGHUP);
559 : : }
560 : :
561 : 27 : sync_status = get_and_validate_seq_info(slot, &sequence_rel,
562 : : &seqinfo, &seqidx);
563 [ + + ]: 27 : if (sync_status == COPYSEQ_SUCCESS)
564 : 22 : sync_status = copy_sequence(seqinfo,
565 : 22 : sequence_rel->rd_rel->relowner);
566 : :
567 [ + + - + : 27 : switch (sync_status)
+ - ]
568 : : {
569 : 22 : case COPYSEQ_SUCCESS:
570 [ - + ]: 22 : elog(DEBUG1,
571 : : "logical replication synchronization for subscription \"%s\", sequence \"%s.%s\" has finished",
572 : : MySubscription->name, seqinfo->nspname,
573 : : seqinfo->seqname);
574 : 22 : batch_succeeded_count++;
575 : 22 : break;
576 : 3 : case COPYSEQ_MISMATCH:
577 : :
578 : : /*
579 : : * Remember mismatched sequences in a long-lived memory
580 : : * context since these will be used after the transaction
581 : : * is committed.
582 : : */
583 : 3 : oldctx = MemoryContextSwitchTo(ApplyContext);
584 : 3 : mismatched_seqs_idx = lappend_int(mismatched_seqs_idx,
585 : : seqidx);
586 : 3 : MemoryContextSwitchTo(oldctx);
587 : 3 : batch_mismatched_count++;
588 : 3 : break;
589 : 0 : case COPYSEQ_SUBSCRIBER_INSUFFICIENT_PERM:
590 : :
591 : : /*
592 : : * Remember sequences with insufficient privileges in a
593 : : * long-lived memory context since these will be used
594 : : * after the transaction is committed.
595 : : */
596 : 0 : oldctx = MemoryContextSwitchTo(ApplyContext);
597 : 0 : sub_insuffperm_seqs_idx = lappend_int(sub_insuffperm_seqs_idx,
598 : : seqidx);
599 : 0 : MemoryContextSwitchTo(oldctx);
600 : 0 : batch_sub_insuffperm_count++;
601 : 0 : break;
602 : 1 : case COPYSEQ_PUBLISHER_INSUFFICIENT_PERM:
603 : :
604 : : /*
605 : : * Remember sequences for which the publisher lacks the
606 : : * privileges required by pg_get_sequence_data().
607 : : */
608 : 1 : oldctx = MemoryContextSwitchTo(ApplyContext);
609 : 1 : pub_insuffperm_seqs_idx = lappend_int(pub_insuffperm_seqs_idx,
610 : : seqidx);
611 : 1 : MemoryContextSwitchTo(oldctx);
612 : 1 : batch_pub_insuffperm_count++;
613 : 1 : break;
614 : 1 : case COPYSEQ_SKIPPED:
615 : :
616 : : /*
617 : : * Concurrent removal of a sequence on the subscriber is
618 : : * treated as success, since the only viable action is to
619 : : * skip the corresponding sequence data. Missing sequences
620 : : * on the publisher are treated as ERROR.
621 : : */
622 [ - + ]: 1 : if (seqinfo->found_on_pub)
623 : : {
624 [ # # ]: 0 : ereport(LOG,
625 : : errmsg("skip synchronization of sequence \"%s.%s\" because it has been dropped concurrently",
626 : : seqinfo->nspname,
627 : : seqinfo->seqname));
628 : 0 : batch_skipped_count++;
629 : : }
630 : 1 : break;
631 : : }
632 : :
633 [ + + ]: 27 : if (sequence_rel)
634 : 25 : table_close(sequence_rel, NoLock);
635 : : }
636 : :
637 : 14 : ExecDropSingleTupleTableSlot(slot);
638 : 14 : walrcv_clear_result(res);
639 : 14 : resetStringInfo(&seqstr);
640 : 14 : resetStringInfo(&cmd);
641 : :
642 : 14 : batch_missing_count = batch_size - (batch_succeeded_count +
643 : 14 : batch_mismatched_count +
644 : 14 : batch_sub_insuffperm_count +
645 : 14 : batch_pub_insuffperm_count +
646 : : batch_skipped_count);
647 : :
648 [ - + ]: 14 : elog(DEBUG1,
649 : : "logical replication sequence synchronization for subscription \"%s\" - batch #%d = %d attempted, %d succeeded, %d mismatched, %d subscriber insufficient permission, %d publisher insufficient permission, %d missing from publisher, %d skipped",
650 : : MySubscription->name,
651 : : (cur_batch_base_index / MAX_SEQUENCES_SYNC_PER_BATCH) + 1,
652 : : batch_size, batch_succeeded_count, batch_mismatched_count,
653 : : batch_sub_insuffperm_count, batch_pub_insuffperm_count, batch_missing_count, batch_skipped_count);
654 : :
655 : : /* Commit this batch, and prepare for next batch */
656 : 14 : CommitTransactionCommand();
657 : :
658 [ + + ]: 14 : if (batch_missing_count)
659 : : {
660 [ + + ]: 13 : for (int idx = cur_batch_base_index; idx < cur_batch_base_index + batch_size; idx++)
661 : : {
662 : : LogicalRepSequenceInfo *seqinfo =
663 : 10 : (LogicalRepSequenceInfo *) list_nth(seqinfos, idx);
664 : :
665 : : /* If the sequence was not found on publisher, record it */
666 [ + + ]: 10 : if (!seqinfo->found_on_pub)
667 : 3 : missing_seqs_idx = lappend_int(missing_seqs_idx, idx);
668 : : }
669 : : }
670 : :
671 : : /*
672 : : * cur_batch_base_index is not incremented sequentially because some
673 : : * sequences may be missing, and the number of fetched rows may not
674 : : * match the batch size.
675 : : */
676 : 14 : cur_batch_base_index += batch_size;
677 : : }
678 : :
679 : : /* Report mismatches, permission issues, or missing sequences */
680 : 14 : report_sequence_errors(mismatched_seqs_idx, sub_insuffperm_seqs_idx,
681 : : pub_insuffperm_seqs_idx, missing_seqs_idx);
682 : 7 : }
683 : :
684 : : /*
685 : : * Identifies sequences that require synchronization and initiates the
686 : : * synchronization process.
687 : : */
688 : : static void
689 : 14 : LogicalRepSyncSequences(void)
690 : : {
691 : : char *err;
692 : : bool must_use_password;
693 : : Relation rel;
694 : : HeapTuple tup;
695 : : ScanKeyData skey[2];
696 : : SysScanDesc scan;
697 : 14 : Oid subid = MyLogicalRepWorker->subid;
698 : : StringInfoData app_name;
699 : :
700 : 14 : StartTransactionCommand();
701 : :
702 : 14 : rel = table_open(SubscriptionRelRelationId, AccessShareLock);
703 : :
704 : 14 : ScanKeyInit(&skey[0],
705 : : Anum_pg_subscription_rel_srsubid,
706 : : BTEqualStrategyNumber, F_OIDEQ,
707 : : ObjectIdGetDatum(subid));
708 : :
709 : 14 : ScanKeyInit(&skey[1],
710 : : Anum_pg_subscription_rel_srsubstate,
711 : : BTEqualStrategyNumber, F_CHAREQ,
712 : : CharGetDatum(SUBREL_STATE_INIT));
713 : :
714 : 14 : scan = systable_beginscan(rel, InvalidOid, false,
715 : : NULL, 2, skey);
716 [ + + ]: 44 : while (HeapTupleIsValid(tup = systable_getnext(scan)))
717 : : {
718 : : Form_pg_subscription_rel subrel;
719 : : LogicalRepSequenceInfo *seq;
720 : : Relation sequence_rel;
721 : : MemoryContext oldctx;
722 : :
723 [ - + ]: 30 : CHECK_FOR_INTERRUPTS();
724 : :
725 : 30 : subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
726 : :
727 : 30 : sequence_rel = try_table_open(subrel->srrelid, RowExclusiveLock);
728 : :
729 : : /* Skip if sequence was dropped concurrently */
730 [ - + ]: 30 : if (!sequence_rel)
731 : 0 : continue;
732 : :
733 : : /* Skip if the relation is not a sequence */
734 [ + + ]: 30 : if (sequence_rel->rd_rel->relkind != RELKIND_SEQUENCE)
735 : : {
736 : 1 : table_close(sequence_rel, NoLock);
737 : 1 : continue;
738 : : }
739 : :
740 : : /*
741 : : * Worker needs to process sequences across transaction boundary, so
742 : : * allocate them under long-lived context.
743 : : */
744 : 29 : oldctx = MemoryContextSwitchTo(ApplyContext);
745 : :
746 : 29 : seq = palloc0_object(LogicalRepSequenceInfo);
747 : 29 : seq->localrelid = subrel->srrelid;
748 : 29 : seq->nspname = get_namespace_name(RelationGetNamespace(sequence_rel));
749 : 29 : seq->seqname = pstrdup(RelationGetRelationName(sequence_rel));
750 : 29 : seqinfos = lappend(seqinfos, seq);
751 : :
752 : 29 : MemoryContextSwitchTo(oldctx);
753 : :
754 : 29 : table_close(sequence_rel, NoLock);
755 : : }
756 : :
757 : : /* Cleanup */
758 : 14 : systable_endscan(scan);
759 : 14 : table_close(rel, AccessShareLock);
760 : :
761 : 14 : CommitTransactionCommand();
762 : :
763 : : /*
764 : : * Exit early if no catalog entries found, likely due to concurrent drops.
765 : : */
766 [ - + ]: 14 : if (!seqinfos)
767 : 0 : return;
768 : :
769 : : /* Is the use of a password mandatory? */
770 [ + - ]: 28 : must_use_password = MySubscription->passwordrequired &&
771 [ - + ]: 14 : !MySubscription->ownersuperuser;
772 : :
773 : 14 : initStringInfo(&app_name);
774 : 14 : appendStringInfo(&app_name, "pg_%u_sequence_sync_" UINT64_FORMAT,
775 : 14 : MySubscription->oid, GetSystemIdentifier());
776 : :
777 : : /*
778 : : * Establish the connection to the publisher for sequence synchronization.
779 : : */
780 : 14 : LogRepWorkerWalRcvConn =
781 : 14 : walrcv_connect(MySubscription->conninfo, true, true,
782 : : must_use_password,
783 : : app_name.data, &err);
784 [ - + ]: 14 : if (LogRepWorkerWalRcvConn == NULL)
785 [ # # ]: 0 : ereport(ERROR,
786 : : errcode(ERRCODE_CONNECTION_FAILURE),
787 : : errmsg("sequencesync worker for subscription \"%s\" could not connect to the publisher: %s",
788 : : MySubscription->name, err));
789 : :
790 : 14 : pfree(app_name.data);
791 : :
792 : 14 : copy_sequences(LogRepWorkerWalRcvConn);
793 : : }
794 : :
795 : : /*
796 : : * Execute the initial sync with error handling. Disable the subscription,
797 : : * if required.
798 : : *
799 : : * Note that we don't handle FATAL errors which are probably because of system
800 : : * resource error and are not repeatable.
801 : : */
802 : : static void
803 : 14 : start_sequence_sync(void)
804 : : {
805 : : Assert(am_sequencesync_worker());
806 : :
807 [ + + ]: 14 : PG_TRY();
808 : : {
809 : : /* Call initial sync. */
810 : 14 : LogicalRepSyncSequences();
811 : : }
812 : 7 : PG_CATCH();
813 : : {
814 [ - + ]: 7 : if (MySubscription->disableonerr)
815 : 0 : DisableSubscriptionAndExit();
816 : : else
817 : : {
818 : : /*
819 : : * Report the worker failed during sequence synchronization. Abort
820 : : * the current transaction so that the stats message is sent in an
821 : : * idle state.
822 : : */
823 : 7 : AbortOutOfAnyTransaction();
824 : 7 : pgstat_report_subscription_error(MySubscription->oid);
825 : :
826 : 7 : PG_RE_THROW();
827 : : }
828 : : }
829 [ - + ]: 7 : PG_END_TRY();
830 : 7 : }
831 : :
832 : : /* Logical Replication sequencesync worker entry point */
833 : : void
834 : 14 : SequenceSyncWorkerMain(Datum main_arg)
835 : : {
836 : 14 : int worker_slot = DatumGetInt32(main_arg);
837 : :
838 : 14 : SetupApplyOrSyncWorker(worker_slot);
839 : :
840 : 14 : start_sequence_sync();
841 : :
842 : 7 : FinishSyncWorker();
843 : : }
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