Horton

Fix possible crash in add_paths_to_append_rel()

David Rowley <drowley@postgresql.org>

View on postgr.es
Commit: fc4089f3c65a5f1b413a3299ba02b66a8e5e37d0
Author: David Rowley <drowley@postgresql.org>
Date: 2023-10-10T03:50:03Z
Releases: 17.0 
Fix possible crash in add_paths_to_append_rel()

While working on a8a968a82, I failed to consider that
cheapest_startup_path can be NULL when there is no non-parameterized
path in the pathlist.  This is well documented in set_cheapest(), I just
failed to notice.

Here we adjust the code to just check if the RelOptInfo has a
cheapest_startup_path set before adding it to the startup_subpaths list.

Reported-by: Richard Guo
Author: Richard Guo
Discussion: https://postgr.es/m/CAMbWs49w3t03V69XhdCuw+GDwivny4uQUxrkVp6Gejaspt0wMQ@mail.gmail.com

Files

PathChange+/−
src/backend/optimizer/path/allpaths.c modified +7 −4
src/test/regress/expected/union.out modified +16 −0
src/test/regress/sql/union.sql modified +8 −1

Discussion