| From: | Timur Magomedov <t(dot)magomedov(at)postgrespro(dot)ru> |
|---|---|
| To: | Peter Smith <smithpb2250(at)gmail(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Cc: | Tomas Vondra <tomas(at)vondra(dot)me>, "Aya Iwata (Fujitsu)" <iwata(dot)aya(at)fujitsu(dot)com>, Japin Li <japinli(at)hotmail(dot)com>, shveta malik <shveta(dot)malik(at)gmail(dot)com> |
| Subject: | Re: [WIP]Vertical Clustered Index (columnar store extension) - take2 |
| Date: | 2025-09-17 15:15:00 |
| Message-ID: | 149d6694c0c5a789b0ee865e80109022002bade5.camel@postgrespro.ru |
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| Lists: | pgsql-hackers |
Hello Peter!
I've found (using valgrind) some cases of reading random garbage after
allocated memory. Investigation showed this was caused by converting
some nodes to VciScanState* even if they have smaller size allocated
originally. So accessing VciScanState fields was accessing memory after
palloc'ed memory which could be used by any other allocation.
I think converting to VciScanState* is only valid for nodes with tag
T_CustomScanState so here is a patch that adds assertions for this:
0001-Assert-corrrect-node-tags-when-casting-to-VciScanSta.patch
VCI v23 passes the tests with this patch applied.
There are queries that fail unfortunately. I've added one of them to
bugs.sql:
0002-Reproducer-of-invalid-cast-to-VciScanState.patch
Node with tag 420 (T_NestLoopState) is cast to VciScanState* that fails
newly added assertion.
I'm not sure where to look next to fix this. Looking forward for you
comments and ideas.
--
Regards,
Timur Magomedov
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Assert-corrrect-node-tags-when-casting-to-VciScanSta.patch | text/x-patch | 5.4 KB |
| 0002-Reproducer-of-invalid-cast-to-VciScanState.patch | text/x-patch | 1.2 KB |
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