mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix race condition in drop subscription's handling of tablesync slots.

Browse Source 
Commit ce0fdbfe97 made tablesync slots permanent and allow Drop
Subscription to drop such slots. However, it is possible that before
tablesync worker could get the acknowledgment of slot creation, drop
subscription stops it and that can lead to a dangling slot on the
publisher. Prevent cancel/die interrupts while creating a slot in the
tablesync worker.

Reported-by: Thomas Munro as per buildfarm
Author: Amit Kapila
Reviewed-by: Vignesh C, Takamichi Osumi
Discussion: https://postgr.es/m/CA+hUKGJG9dWpw1cOQ2nzWU8PHjm=PTraB+KgE5648K9nTfwvxg@mail.gmail.com
This commit is contained in:
Amit Kapila 2021-03-17 08:15:12 +05:30
parent 7efeb214ad
commit 6b67d72b60
1 changed files with 7 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/backend/replication/logical/tablesync.c
View File

@ -1051,9 +1051,16 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
* Create a new permanent logical decoding slot. This slot will be used
* for the catchup phase after COPY is done, so tell it to use the
* snapshot to make the final data consistent.
*
* Prevent cancel/die interrupts while creating slot here because it is
* possible that before the server finishes this command, a concurrent
* drop subscription happens which would complete without removing this
* slot leading to a dangling slot on the server.
*/
HOLD_INTERRUPTS();
walrcv_create_slot(wrconn, slotname, false /* permanent */ ,
CRS_USE_SNAPSHOT, origin_startpos);
RESUME_INTERRUPTS();
/*
* Setup replication origin tracking. The purpose of doing this before the