database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Introduce a new GUC 'standby_slot_names'.

Browse Source 
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
This commit is contained in:
Amit Kapila
2024-03-08 08:10:45 +05:30
parent 453c468737
commit bf279ddd1c
18 changed files with 918 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/replication/logical/logicalfuncs.c
View File

@ -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;
/*