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| author | Amit Kapila <akapila@postgresql.org> | 2024-03-08 08:10:45 +0530 |
|---|---|---|
| committer | Amit Kapila <akapila@postgresql.org> | 2024-03-08 08:10:45 +0530 |
| commit | bf279ddd1c28ce0251446ee90043a4cb96e5db0f (patch) | |
| tree | 642eb01435995795793fc61cedcc66949c824f1d /src/backend/replication/logical/logicalfuncs.c | |
| parent | 453c46873774219243501b8efc16b2b5a5e9d194 (diff) | |
| download | postgresql-bf279ddd1c28ce0251446ee90043a4cb96e5db0f.tar.gz postgresql-bf279ddd1c28ce0251446ee90043a4cb96e5db0f.zip | |
Introduce a new GUC 'standby_slot_names'.
This patch provides a way to ensure that physical standbys that are
potential failover candidates have received and flushed changes before
the primary server making them visible to subscribers. Doing so guarantees
that the promoted standby server is not lagging behind the subscribers
when a failover is necessary.
The logical walsender now guarantees that all local changes are sent and
flushed to the standby servers corresponding to the replication slots
specified in 'standby_slot_names' before sending those changes to the
subscriber.
Additionally, the SQL functions pg_logical_slot_get_changes,
pg_logical_slot_peek_changes and pg_replication_slot_advance are modified
to ensure that they process changes for failover slots only after physical
slots specified in 'standby_slot_names' have confirmed WAL receipt for those.
Author: Hou Zhijie and Shveta Malik
Reviewed-by: Masahiko Sawada, Peter Smith, Bertrand Drouvot, Ajin Cherian, Nisha Moond, Amit Kapila
Discussion: https://postgr.es/m/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
Diffstat (limited to 'src/backend/replication/logical/logicalfuncs.c')
| -rw-r--r-- | src/backend/replication/logical/logicalfuncs.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/backend/replication/logical/logicalfuncs.c b/src/backend/replication/logical/logicalfuncs.c index a1ff631e5ed..b4dd5cce75b 100644 --- a/src/backend/replication/logical/logicalfuncs.c +++ b/src/backend/replication/logical/logicalfuncs.c @@ -105,6 +105,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin MemoryContext per_query_ctx; MemoryContext oldcontext; XLogRecPtr end_of_wal; + XLogRecPtr wait_for_wal_lsn; LogicalDecodingContext *ctx; ResourceOwner old_resowner = CurrentResourceOwner; ArrayType *arr; @@ -224,6 +225,17 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin NameStr(MyReplicationSlot->data.plugin), format_procedure(fcinfo->flinfo->fn_oid)))); + /* + * Wait for specified streaming replication standby servers (if any) + * to confirm receipt of WAL up to wait_for_wal_lsn. + */ + if (XLogRecPtrIsInvalid(upto_lsn)) + wait_for_wal_lsn = end_of_wal; + else + wait_for_wal_lsn = Min(upto_lsn, end_of_wal); + + WaitForStandbyConfirmation(wait_for_wal_lsn); + ctx->output_writer_private = p; /* |