| From: | Peter Eisentraut <peter(at)eisentraut(dot)org> |
|---|---|
| To: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Daniel Verite <daniel(at)manitou-mail(dot)org>, Paul A Jungwirth <pj(at)illuminatedcomputing(dot)com> |
| Subject: | Re: Support LIKE with nondeterministic collations |
| Date: | 2024-11-12 07:45:23 |
| Message-ID: | 62156cde-b2c5-4375-b47a-9730aa8f7b5e@eisentraut.org |
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| Thread: | |
| Lists: | pgsql-hackers |
On 11.11.24 14:25, Heikki Linnakangas wrote:
> Sadly the algorithm is O(n^2) with non-deterministic collations.Is there
> any way this could be optimized? We make no claims on how expensive any
> functions or operators are, so I suppose a slow implementation is
> nevertheless better than throwing an error.
Yeah, maybe someone comes up with new ideas in the future.
> Let's at least add some CHECK_FOR_INTERRUPTS(). For example, this takes
> a very long time and is uninterruptible:
>
> SELECT repeat('x', 100000) LIKE '%xxxy%' COLLATE ignore_accents;
Good idea. Here is a new patch version with an interrupt check.
| Attachment | Content-Type | Size |
|---|---|---|
| v7-0001-Support-LIKE-with-nondeterministic-collations.patch | text/plain | 25.8 KB |
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