diff options
| -rw-r--r-- | contrib/test_decoding/expected/catalog_change_snapshot.out | 56 | ||||
| -rw-r--r-- | contrib/test_decoding/specs/catalog_change_snapshot.spec | 20 | ||||
| -rw-r--r-- | src/backend/replication/logical/snapbuild.c | 50 |
3 files changed, 106 insertions, 20 deletions
diff --git a/contrib/test_decoding/expected/catalog_change_snapshot.out b/contrib/test_decoding/expected/catalog_change_snapshot.out index dc4f9b7018f..d2a4bdfcc13 100644 --- a/contrib/test_decoding/expected/catalog_change_snapshot.out +++ b/contrib/test_decoding/expected/catalog_change_snapshot.out @@ -1,4 +1,4 @@ -Parsed test spec with 2 sessions +Parsed test spec with 3 sessions starting permutation: s0_init s0_begin s0_savepoint s0_truncate s1_checkpoint s1_get_changes s0_commit s0_begin s0_insert s1_checkpoint s1_get_changes s0_commit s1_get_changes step s0_init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding'); @@ -42,3 +42,57 @@ COMMIT stop (1 row) + +starting permutation: s0_init s0_begin s0_truncate s2_begin s2_truncate s1_checkpoint s1_get_changes s0_commit s0_begin s0_insert s1_checkpoint s1_get_changes s2_commit s1_checkpoint s1_get_changes s0_commit s1_get_changes +step s0_init: SELECT 'init' FROM pg_create_logical_replication_slot('isolation_slot', 'test_decoding'); +?column? +-------- +init +(1 row) + +step s0_begin: BEGIN; +step s0_truncate: TRUNCATE tbl1; +step s2_begin: BEGIN; +step s2_truncate: TRUNCATE tbl2; +step s1_checkpoint: CHECKPOINT; +step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0'); +data +---- +(0 rows) + +step s0_commit: COMMIT; +step s0_begin: BEGIN; +step s0_insert: INSERT INTO tbl1 VALUES (1); +step s1_checkpoint: CHECKPOINT; +step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0'); +data +--------------------------------------- +BEGIN +table public.tbl1: TRUNCATE: (no-flags) +COMMIT +(3 rows) + +step s2_commit: COMMIT; +step s1_checkpoint: CHECKPOINT; +step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0'); +data +--------------------------------------- +BEGIN +table public.tbl2: TRUNCATE: (no-flags) +COMMIT +(3 rows) + +step s0_commit: COMMIT; +step s1_get_changes: SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0'); +data +------------------------------------------------------------- +BEGIN +table public.tbl1: INSERT: val1[integer]:1 val2[integer]:null +COMMIT +(3 rows) + +?column? +-------- +stop +(1 row) + diff --git a/contrib/test_decoding/specs/catalog_change_snapshot.spec b/contrib/test_decoding/specs/catalog_change_snapshot.spec index 2971ddc69cb..ff8f68489bb 100644 --- a/contrib/test_decoding/specs/catalog_change_snapshot.spec +++ b/contrib/test_decoding/specs/catalog_change_snapshot.spec @@ -3,12 +3,15 @@ setup { DROP TABLE IF EXISTS tbl1; + DROP TABLE IF EXISTS tbl2; CREATE TABLE tbl1 (val1 integer, val2 integer); + CREATE TABLE tbl2 (val1 integer, val2 integer); } teardown { DROP TABLE tbl1; + DROP TABLE tbl2; SELECT 'stop' FROM pg_drop_replication_slot('isolation_slot'); } @@ -26,6 +29,12 @@ setup { SET synchronous_commit=on; } step "s1_checkpoint" { CHECKPOINT; } step "s1_get_changes" { SELECT data FROM pg_logical_slot_get_changes('isolation_slot', NULL, NULL, 'skip-empty-xacts', '1', 'include-xids', '0'); } +session "s2" +setup { SET synchronous_commit=on; } +step "s2_begin" { BEGIN; } +step "s2_truncate" { TRUNCATE tbl2; } +step "s2_commit" { COMMIT; } + # For the transaction that TRUNCATEd the table tbl1, the last decoding decodes # only its COMMIT record, because it starts from the RUNNING_XACTS record emitted # during the first checkpoint execution. This transaction must be marked as @@ -37,3 +46,14 @@ step "s1_get_changes" { SELECT data FROM pg_logical_slot_get_changes('isolation_ # record written by bgwriter. One might think we can either stop the bgwriter or # increase LOG_SNAPSHOT_INTERVAL_MS but it's not practical via tests. permutation "s0_init" "s0_begin" "s0_savepoint" "s0_truncate" "s1_checkpoint" "s1_get_changes" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes" + +# Test that we can purge the old catalog modifying transactions after restoring +# them from the serialized snapshot. The first checkpoint will serialize the list +# of two catalog modifying xacts. The purpose of the second checkpoint is to allow +# partial pruning of the list of catalog modifying xact. The third checkpoint +# followed by get_changes establishes a restart_point at the first checkpoint LSN. +# The last get_changes will start decoding from the first checkpoint which +# restores the list of catalog modifying xacts and then while decoding the second +# checkpoint record it prunes one of the xacts in that list and when decoding the +# next checkpoint, it will completely prune that list. +permutation "s0_init" "s0_begin" "s0_truncate" "s2_begin" "s2_truncate" "s1_checkpoint" "s1_get_changes" "s0_commit" "s0_begin" "s0_insert" "s1_checkpoint" "s1_get_changes" "s2_commit" "s1_checkpoint" "s1_get_changes" "s0_commit" "s1_get_changes" diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index 1ff2c12240d..bf72ad45ec7 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -969,28 +969,40 @@ SnapBuildPurgeOlderTxn(SnapBuild *builder) pfree(workspace); /* - * Either all the xacts got purged or none. It is only possible to - * partially remove the xids from this array if one or more of the xids - * are still running but not all. That can happen if we start decoding - * from a point (LSN where the snapshot state became consistent) where all - * the xacts in this were running and then at least one of those got - * committed and a few are still running. We will never start from such a - * point because we won't move the slot's restart_lsn past the point where - * the oldest running transaction's restart_decoding_lsn is. + * Purge xids in ->catchange as well. The purged array must also be sorted + * in xidComparator order. */ - if (builder->catchange.xcnt == 0 || - TransactionIdFollowsOrEquals(builder->catchange.xip[0], - builder->xmin)) - return; + if (builder->catchange.xcnt > 0) + { + /* + * Since catchange.xip is sorted, we find the lower bound of xids that + * are still interesting. + */ + for (off = 0; off < builder->catchange.xcnt; off++) + { + if (TransactionIdFollowsOrEquals(builder->catchange.xip[off], + builder->xmin)) + break; + } - Assert(TransactionIdFollows(builder->xmin, - builder->catchange.xip[builder->catchange.xcnt - 1])); - pfree(builder->catchange.xip); - builder->catchange.xip = NULL; - builder->catchange.xcnt = 0; + surviving_xids = builder->catchange.xcnt - off; - elog(DEBUG3, "purged catalog modifying transactions, oldest running xid %u", - builder->xmin); + if (surviving_xids > 0) + { + memmove(builder->catchange.xip, &(builder->catchange.xip[off]), + surviving_xids * sizeof(TransactionId)); + } + else + { + pfree(builder->catchange.xip); + builder->catchange.xip = NULL; + } + + elog(DEBUG3, "purged catalog modifying transactions from %u to %u, xmin: %u, xmax: %u", + (uint32) builder->catchange.xcnt, (uint32) surviving_xids, + builder->xmin, builder->xmax); + builder->catchange.xcnt = surviving_xids; + } } /* |