From: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
---|---|
To: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jaime Casanova <jaime(dot)casanova(at)2ndquadrant(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: FailedAssertion on partprune |
Date: | 2018-08-01 14:35:09 |
Message-ID: | CAKJS1f9e7hHYP9SaT=-_RR4jdmm9VCgtDoC3-60s97EMjcfGWg@mail.gmail.com |
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Lists: | pgsql-hackers |
On 31 July 2018 at 11:25, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
> Not looking at the code right now either, but removing that assert and
> then removing the TABLESAMPLE clause, the query returns identical
> results with and without pruning, so maybe you're right. No time for
> further looking now.
I thought about this a bit more and it seems fine just to remove the
Assert. The patch that's pending in [1] adds all the correct handling
for subplans that don't belong in any partition hierarchy. That's not
the case for Jaime's plan, but those sub-partitioned tables will be
identified just like any other partition by the run-time pruning code
and can be pruned in the same way.
The attached patch removes the Assert, but I think it should be
probably be done as part of [1]'s patch since that's also adding the
code to handle subplans for tables that don't belong in the partition
hierarchy.
I also spent a bit of time trying to create a simple test case for
this and I've discovered that it's really not very easy and I have
doubts about how stable such a plan might be.
> (SELECT 'Jaime' <> 'Jamie' COLLATE es_EC)
Apologies. It was a finger auto-pilot malfunction.
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
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remove_incorrect_partprune_assert.patch | application/octet-stream | 549 bytes |
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