database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-08-28 18:48:04 +03:00
Code Activity

Fix fetching default toast value during decoding of in-progress transactions.

Browse Source 
During logical decoding of in-progress transactions, we perform the toast
table scan while fetching the default toast value for an attribute. We
forgot to initialize the flag during this scan to indicate that the system
table scan is in progress. We need this flag to ensure that during logical
decoding we never directly access the tableam or heap APIs because we check
for concurrent aborts only in systable_* APIs.

Reported-by: Alexander Lakhin
Author: Takeshi Ideriha, Hou Zhijie
Reviewed-by: Amit Kapila, Hou Zhijie
Backpatch-through: 14
Discussion: https://postgr.es/m/18641-6687273b7f15269d@postgresql.org
This commit is contained in:
Amit Kapila
2024-10-07 14:53:18 +05:30
parent aef75219cc
commit 8175a7d11f
3 changed files with 54 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/access/index/genam.c
View File

@@ -703,6 +703,14 @@ systable_beginscan_ordered(Relation heapRelation,
index_rescan(sysscan->iscan, key, nkeys, NULL, 0);
sysscan->scan = NULL;
/*
* If CheckXidAlive is set then set a flag to indicate that system table
* scan is in-progress. See detailed comments in xact.c where these
* variables are declared.
*/
if (TransactionIdIsValid(CheckXidAlive))
bsysscan = true;
return sysscan;
}
@@ -747,6 +755,14 @@ systable_endscan_ordered(SysScanDesc sysscan)
index_endscan(sysscan->iscan);
if (sysscan->snapshot)
UnregisterSnapshot(sysscan->snapshot);
/*
* Reset the bsysscan flag at the end of the systable scan. See detailed
* comments in xact.c where these variables are declared.
*/
if (TransactionIdIsValid(CheckXidAlive))
bsysscan = false;
pfree(sysscan);
}