database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-24 14:22:24 +03:00
Code Activity

Fix ALTER SUBSCRIPTION ... SET PUBLICATION ... command.

Browse Source 
The problem is that ALTER SUBSCRIPTION ... SET PUBLICATION ... will lead
to restarting of apply worker and after the restart, the apply worker will
use the existing slot and replication origin corresponding to the
subscription. Now, it is possible that before the restart, the origin has
not been updated, and the WAL start location points to a location before
where PUBLICATION pointed to by SET PUBLICATION doesn't exist, and that
can lead to an error like: "ERROR:  publication "pub1" does not exist".
Once this error occurs, apply worker will never be able to proceed and
will always return the same error.

We decided to skip loading the publication if the publication does not
exist. The publication is loaded later and updates the relation entry when
the publication gets created.

We decided not to backpatch this as this is a behaviour change, and we don't
see field reports. This problem has been found by intermittent buildfarm
failures.

Author: vignesh C <vignesh21@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/flat/CALDaNm0-n8FGAorM%2BbTxkzn%2BAOUyx5%3DL_XmnvOP6T24%2B-NcBKg%40mail.gmail.com
Discussion: https://postgr.es/m/CAA4eK1+T-ETXeRM4DHWzGxBpKafLCp__5bPA_QZfFQp7-0wj4Q@mail.gmail.com
This commit is contained in:
Amit Kapila
2025-03-14 08:57:40 +05:30
parent 4618045bee
commit 7c99dc587a
2 changed files with 57 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/replication/pgoutput/pgoutput.c
View File

@ -1764,6 +1764,11 @@ pgoutput_shutdown(LogicalDecodingContext *ctx)
/*
* Load publications from the list of publication names.
*
* Here, we skip the publications that don't exist yet. This will allow us
* to silently continue the replication in the absence of a missing publication.
* This is required because we allow the users to create publications after they
* have specified the required publications at the time of replication start.
*/
static List *
LoadPublications(List *pubnames)
@ -1774,9 +1779,16 @@ LoadPublications(List *pubnames)
foreach(lc, pubnames)
{
char *pubname = (char *) lfirst(lc);
Publication *pub = GetPublicationByName(pubname, false);
Publication *pub = GetPublicationByName(pubname, true);
result = lappend(result, pub);
if (pub)
result = lappend(result, pub);
else
ereport(WARNING,
errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("skipped loading publication: %s", pubname),
errdetail("The publication does not exist at this point in the WAL."),
errhint("Create the publication if it does not exist."));
}
return result;