Thread: BUG #18868: /src/backend/optimizer/path/joinrels.c list_head can be NULL
BUG #18868: /src/backend/optimizer/path/joinrels.c list_head can be NULL
From
PG Bug reporting form
Date:
The following bug has been logged on the website: Bug reference: 18868 Logged by: Daniel Elishakov Email address: dan-eli@mail.ru PostgreSQL version: 17.4 Operating system: ubuntu 20.04 Description: Pointers, returned from function 'list_head' at joinrels.c:1527 and 1528, may be NULL and is dereferenced at joinrels.c:1550 and 1551.
Re: BUG #18868: /src/backend/optimizer/path/joinrels.c list_head can be NULL
From
"Euler Taveira"
Date:
On Wed, Mar 26, 2025, at 7:16 AM, PG Bug reporting form wrote:
Pointers, returned from function 'list_head' at joinrels.c:1527 and 1528,may be NULL and is dereferenced at joinrels.c:1550 and 1551.
joinrels.c:
compute_partition_bounds(root, rel1, rel2, joinrel, parent_sjinfo,
&parts1, &parts2);
if (joinrel->partbounds_merged)
{
lcr1 = list_head(parts1);
lcr2 = list_head(parts2);
}
Did you read compute_partition_bounds()?
if (joinrel->partbounds_merged)
{
get_matching_part_pairs(root, joinrel, rel1, rel2,
parts1, parts2);
Assert(list_length(*parts1) == joinrel->nparts);
Assert(list_length(*parts2) == joinrel->nparts);
}
parts1 and parts2 uses the same condition. I expect that if there is any bug
related to pointer deference, the assert(s) should report. Do you have a test
case that exposes this issue?