From: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
---|---|
To: | Tomas Vondra <tomas(dot)vondra(at)postgresql(dot)org> |
Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org |
Subject: | cache lookup failed for statistics object 123 |
Date: | 2021-05-05 21:09:47 |
Message-ID: | 20210505210947.GA27406@telsasoft.com |
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Lists: | pgsql-hackers |
Per sqlsmith.
postgres=# SELECT pg_get_statisticsobjdef_expressions(123);
ERROR: cache lookup failed for statistics object 123
postgres=# \errverbose
ERROR: XX000: cache lookup failed for statistics object 123
LOCATION: pg_get_statisticsobjdef_expressions, ruleutils.c:1762
The expectation is that sql callable functions should return null rather than
hitting elog().
In the 003 patch, I wonder if this part should be updated, too:
| ... which can greatly improve query plans that use the expression index.
It can improve queries even that don't use the index, right ?
Say, if a query has f(x) = 11, and the MCV list for the expression shows that
50% of the table has f(x)=11, then the query might decide to *not* use an index
scan.
--
Justin
Attachment | Content-Type | Size |
---|---|---|
0001-Return-NULL-rather-than-elog-ERROR-for-sql-callable-.patch | text/x-diff | 1.0 KB |
0002-Comment-typos-extended-stats-a4d75c86b-and-518442c7f.patch | text/x-diff | 1.6 KB |
0003-Mention-statistics-objects.patch | text/x-diff | 1003 bytes |
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