| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Tomas Vondra <tomas(at)vondra(dot)me> |
| Cc: | Mark Dilger <mark(dot)dilger(at)enterprisedb(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com> |
| Subject: | Re: Adding skip scan (including MDAM style range skip scan) to nbtree |
| Date: | 2025-05-09 16:09:01 |
| Message-ID: | CAH2-Wz=LRs1uoc3Nkg5C=asCN5_LeZrObiOTvp8DvQs_KqVwAg@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, May 9, 2025 at 11:55 AM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> Note that "sizeof(FmgrInfo)" is 48 bytes. Prior to skip scan,
> RelationData.rd_supportinfo would have required 48*5=240 bytes. After
> skip scan, it would have required 48*6=288 bytes. Maybe 256 bytes is
> some kind of critical threshold, someplace?
Can you try it with the attached patch?
The patch disables skip support entirely, in a way that should
eliminate whatever the inherent overhead of adding a sixth support
routine to nbtree was. It does not remove skip scan itself (that
should still work with queries that are actually eligible to use skip
scan, albeit slightly less efficiently with some opclasses).
--
Peter Geoghegan
| Attachment | Content-Type | Size |
|---|---|---|
| 0001-Remove-nbtree-support-routine-6.patch | application/octet-stream | 10.7 KB |
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