Re: Large expressions in indexes can't be stored (non-TOASTable)

Hello Nathan,

19.09.2024 21:36, Nathan Bossart wrote:
> On Thu, Sep 19, 2024 at 12:00:00PM +0300, Alexander Lakhin wrote:
>> completed with:
>> DROP INDEX CONCURRENTLY def_vec_quantizer_idx;
>>
>> triggers an assertion failure:
>> TRAP: failed Assert("HaveRegisteredOrActiveSnapshot()"), File: "toast_internals.c", Line: 668, PID: 3723372
> Ha, that was fast. The attached patch seems to fix the assertion failures.
> It's probably worth checking if any of the adjacent code paths are
> affected, too.
>

Thank you for your attention to that issue!

I've found another two paths to reach that condition:
CREATE INDEX CONCURRENTLY ON def (vec_quantizer(id, :'b'));
ERROR:  cannot fetch toast data without an active snapshot

REINDEX INDEX CONCURRENTLY def_vec_quantizer_idx;
(or REINDEX TABLE CONCURRENTLY def;)
TRAP: failed Assert("HaveRegisteredOrActiveSnapshot()"), File: "toast_internals.c", Line: 668, PID: 2934502
ExceptionalCondition at assert.c:52:13
init_toast_snapshot at toast_internals.c:670:2
toast_delete_datum at toast_internals.c:429:60
toast_tuple_cleanup at toast_helper.c:303:30
heap_toast_insert_or_update at heaptoast.c:335:9
heap_update at heapam.c:3752:14
simple_heap_update at heapam.c:4210:11
CatalogTupleUpdate at indexing.c:324:2
index_concurrently_swap at index.c:1649:2
ReindexRelationConcurrently at indexcmds.c:4270:3
ReindexIndex at indexcmds.c:2962:1
ExecReindex at indexcmds.c:2884:4
ProcessUtilitySlow at utility.c:1570:22
...

Perhaps it would make sense to check all CatalogTupleUpdate(pg_index, ...)
calls (I've found 10 such instances, but haven't checked them yet).

Best regards,
Alexander