Re: Issues with ON CONFLICT UPDATE and REINDEX CONCURRENTLY

Hello Alvaro,

27.11.2025 14:32, Álvaro Herrera wrote:
> Thanks for reviewing. I have pushed it now. Looking at the next one.

I've noticed two failures from skink you could find interesting: [1], [2].
The difference from [2]:
ok 3         - syscache-update-pruned                  94198 ms
not ok 4     - index-concurrently-upsert               14008 ms
ok 5         - reindex-concurrently-upsert             14379 ms

--- /home/bf/bf-build/skink-master/HEAD/pgsql/src/test/modules/injection_points/expected/index-concurrently-upsert.out
2025-11-27 13:38:19.513528475 +0100
+++
/home/bf/bf-build/skink-master/HEAD/pgsql.build/testrun/injection_points/isolation/results/index-concurrently-upsert.out
2025-11-30 00:10:01.697938769 +0100
@@ -107,6 +107,7 @@
 (1 row)

 s1: NOTICE:  notice triggered for injection point pre-invalidate-catalog-snapshot-end
+s1: NOTICE:  notice triggered for injection point pre-invalidate-catalog-snapshot-end
 step s1_start_upsert: <... completed>
 step s2_start_upsert: <... completed>
 step s3_start_create_index: <... completed>

I've managed to reproduce something similar to this diff when running
multiple test instances under Valgrind with parallel. With the attached
patch applied:
for i in {1..40}; do cp -r src/test/modules/injection_points/ src/test/modules/injection_points_$i/; sed -i.bak
"s|src/test/modules/injection_points|src/test/modules/injection_points_$i|"
src/test/modules/injection_points_$i/Makefile; done
make -s check -C src/test/modules/injection_points

and/tmp/extra.config containing:
log_min_messages = INFO
backtrace_functions = 'injection_notice'

for i in {1..10}; do np=5; echo "ITERATION $i"; parallel -j40 --linebuffer --tag PROVE_TESTS="t/099*" NO_TEMP_INSTALL=1
TEMP_CONFIG=/tmp/extra.config make -s check -C src/test/modules/injection_points_{}  ::: `seq $np` || break; done

gives me:
ITERATION 1
...
4       #   Failed test 'regression tests pass'
4       #   at t/099_isolation_regress.pl line 52.
4       #          got: '256'
4       #     expected: '0'

src/test/modules/injection_points_4/tmp_check/log/regress_log_099_isolation_regress contains:
...
ok 11        - index-concurrently-upsert                5282 ms
not ok 12    - index-concurrently-upsert                6347 ms
ok 13        - index-concurrently-upsert                5723 ms
...
--- .../src/test/modules/injection_points_4/expected/index-concurrently-upsert.out 2025-11-30 14:24:29.385133831 +0200
+++ .../src/test/modules/injection_points_4/tmp_check/results/index-concurrently-upsert.out 2025-11-30
16:22:29.168920744 +0200
@@ -78,6 +78,7 @@

 (1 row)

+s1: NOTICE:  notice triggered for injection point pre-invalidate-catalog-snapshot-end
 step s4_wakeup_s2:
    SELECT injection_points_detach('exec-insert-before-insert-speculative');
    SELECT injection_points_wakeup('exec-insert-before-insert-speculative');
=== EOF ===

I can see in the following stack trace for this extra notice:
2025-11-30 16:22:28.465 EET|law|isolation_regression|692c531f.bb652|NOTICE:  notice triggered for injection point
pre-invalidate-catalog-snapshot-end
2025-11-30 16:22:28.465 EET|law|isolation_regression|692c531f.bb652|BACKTRACE:
injection_notice at injection_points.c:278:3
InjectionPointRun at injection_point.c:555:1
InvalidateCatalogSnapshot at snapmgr.c:463:3
LocalExecuteInvalidationMessage at inval.c:831:4
ReceiveSharedInvalidMessages at sinval.c:113:18
AcceptInvalidationMessages at inval.c:970:23
LockRelationOid at lmgr.c:137:3
relation_open at relation.c:58:6
table_open at table.c:44:6
SearchCatCacheMiss at catcache.c:1550:13
SearchCatCacheInternal at catcache.c:1495:9
SearchCatCache1 at catcache.c:1368:1
SearchSysCache1 at syscache.c:227:1
build_coercion_expression at parse_coerce.c:852:8
coerce_type at parse_coerce.c:433:13
coerce_to_target_type at parse_coerce.c:105:11
transformAssignedExpr at parse_target.c:580:4
transformInsertRow at analyze.c:1121:10
transformInsertStmt at analyze.c:988:14
transformStmt at analyze.c:364:13
transformOptionalSelectInto at analyze.c:317:1
transformTopLevelStmt at analyze.c:266:11
parse_analyze_fixedparams at analyze.c:134:10
pg_analyze_and_rewrite_fixedparams at postgres.c:687:10
exec_simple_query at postgres.c:1195:20
PostgresMain at postgres.c:4777:6
BackendInitialize at backend_startup.c:142:1
postmaster_child_launch at launch_backend.c:269:3
BackendStartup at postmaster.c:3598:8
ServerLoop at postmaster.c:1716:10
PostmasterMain at postmaster.c:1403:11
main at main.c:236:2

I also observed:
2025-11-30 15:33:45.746 EET|law|isolation_regression|692c47b4.675e7|NOTICE:  notice triggered for injection point
pre-invalidate-catalog-snapshot-end
2025-11-30 15:33:45.746 EET|law|isolation_regression|692c47b4.675e7|BACKTRACE:
injection_notice at injection_points.c:278:3
InjectionPointRun at injection_point.c:555:1
InvalidateCatalogSnapshot at snapmgr.c:463:3
LocalExecuteInvalidationMessage at inval.c:831:4
ReceiveSharedInvalidMessages at sinval.c:113:18
AcceptInvalidationMessages at inval.c:970:23
LockRelationOid at lmgr.c:137:3
relation_open at relation.c:58:6
table_open at table.c:44:6
CatalogCacheInitializeCache at catcache.c:1131:13
ConditionalCatalogCacheInitializeCache at catcache.c:1092:1
SearchCatCacheInternal at catcache.c:1424:15
SearchCatCache1 at catcache.c:1368:1
SearchSysCache1 at syscache.c:227:1
check_enable_rls at rls.c:66:10
get_row_security_policies at rowsecurity.c:130:15
fireRIRrules at rewriteHandler.c:2218:3
QueryRewrite at rewriteHandler.c:4581:11
pg_rewrite_query at postgres.c:822:20
pg_analyze_and_rewrite_fixedparams at postgres.c:696:19
exec_simple_query at postgres.c:1195:20
PostgresMain at postgres.c:4777:6
BackendInitialize at backend_startup.c:142:1
postmaster_child_launch at launch_backend.c:269:3
BackendStartup at postmaster.c:3598:8
ServerLoop at postmaster.c:1716:10
PostmasterMain at postmaster.c:1403:11
main at main.c:236:2

Could you please look if this can be fixed?

[1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=skink&dt=2025-11-25%2021%3A55%3A00
[2] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=skink&dt=2025-11-29%2021%3A51%3A13

Best regards,
Alexander