Horton

Re: Re: PANIC: invalid index offnum: 186 when processing BRIN indexes in VACUUM

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael.paquier@gmail.com>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Date: 2017-11-03T10:47:23Z
Lists: pgsql-hackers 
Hi,

On 11/02/2017 06:45 PM, Alvaro Herrera wrote:
> Tomas Vondra wrote:
> 
>> Unfortunately, I think we still have a problem ... I've been wondering
>> if we end up producing correct indexes, so I've done a simple test.
> 
> Here's a proposed patch that should fix this problem (and does, in my
> testing).  Would you please give it a try?
> 
> This patch changes two things:
> 
> 1. in VACUUM or brin_summarize_new_values, we only process fully loaded
> ranges, and ignore the partial range at end of table.
> 
> 2. when summarization is requested on the partial range at the end of a
> table, we acquire extension lock on the rel, then compute relation size
> and run summarization with the lock held.  This guarantees that we don't
> miss any pages.  This is bad for concurrency though, so it's only done
> in that specific scenario.
> 

FWIW this patch fixes the issue for me - I can no longer reproduce the
bitmapscan vs. seqscan result discrepancies (even with the extra UPDATE
phase).

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Fix BRIN summarization concurrent with extension

  2. Fix corner-case errors in brin_doupdate().

  3. Rewrite PageIndexDeleteNoCompact into a form that only deletes 1 tuple.

  4. Invent PageIndexTupleOverwrite, and teach BRIN and GiST to use it.

  5. Close some holes in BRIN page assignment