| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
| Cc: | Amit Langote <amitlangote09(at)gmail(dot)com>, Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp>, Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, Rajkumar Raghuwanshi <rajkumar(dot)raghuwanshi(at)enterprisedb(dot)com>, Beena Emerson <memissemerson(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, amul sul <sulamul(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, Dilip Kumar <dilipbalaut(at)gmail(dot)com> |
| Subject: | Re: [HACKERS] Runtime Partition Pruning |
| Date: | 2018-04-07 21:13:31 |
| Message-ID: | 20180407211331.6idzpqp3wsusevwh@alvherre.pgsql |
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| Lists: | pgsql-hackers |
I pushed this patch -- 0001, 0002 and 0003 only. I did not include
anything from 0004 and 0005; I didn't even get to the point of reading
them, so that I could focus on the first part.
I did not find anything to complain about. I made a few adjustments and
asked David to supply a paragraph for perform.sgml (the "Using EXPLAIN"
section) which is included here. I also adopted Jesper's (actually
David's) suggestion of changing "Partitions Pruned" to "Partitions
Removed" in the EXPLAIN output.
I had reservations about a relation_open() in the new executor code. It
seemed a bit odd; we don't have any other relation_open in the executor
anywhere. However, setting up the pruneinfo needs some stuff from
relcache that I don't see a reasonable mechanism to pass through
planner. I asked Andres about it on IM and while he didn't endorse the
patch in any way, his quick opinion was that "it wasn't entirely
insane". I verified that we already hold lock on the relation.
While we didn't get fast pruning support for MergeAppend or the
DELETE/UPDATE parts, I think those are valuable and recommend to
resubmit those for PG12.
Thank you!
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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