Horton

Re: A design for amcheck heapam verification

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-07T02:26:36Z
Lists: pgsql-hackers

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On Wed, Aug 30, 2017 at 9:29 AM, Peter Geoghegan <pg@bowt.ie> wrote:
> On Wed, Aug 30, 2017 at 5:02 AM, Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
>> Eh, if you want to optimize it for the case where debug output is not
>> enabled, make sure to use ereport() not elog().  ereport()
>> short-circuits evaluation of arguments, whereas elog() does not.
>
> I should do that, but it's still not really noticeable.

Since this patch has now bit-rotted, I attach a new revision, V2.
Apart from fixing some Makefile bitrot, this revision also makes some
small tweaks as suggested by Thomas and Alvaro. The documentation is
also revised and expanded, and now discusses practical aspects of the
set membership being tested using a Bloom filter, how that relates to
maintenance_work_mem, and so on.

Note that this revision does not let the Bloom filter caller use their
own dynamic shared memory, which is something that Thomas asked about.
While that could easily be added, I think it should happen later. I
really just wanted to make sure that my Bloom filter was not in some
way fundamentally incompatible with Thomas' planned enhancements to
(parallel) hash join.

-- 
Peter Geoghegan

Commits

  1. Fix non-portable use of round().

  2. Add amcheck verification of heap relations belonging to btree indexes.

  3. Add Bloom filter implementation.

  4. Use ereport not elog for some corrupt-HOT-chain reports.

  5. Introduce 64-bit hash functions with a 64-bit seed.

  6. Upgrade src/port/rint.c to be POSIX-compliant.

  7. Use type "int64" for memory accounting in tuplesort.c/tuplestore.c.