Horton

Re: A design for amcheck heapam verification

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Michael Paquier <michael.paquier@gmail.com>, Peter Geoghegan <pg@bowt.ie>, Alvaro Herrera <alvherre@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-29T17:29:04Z
Lists: pgsql-hackers 
On Thu, Sep 28, 2017 at 11:34 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> FWIW I think if I were attacking that problem the first thing I'd
> probably try would be getting rid of that internal pointer
> filter->bitset in favour of a FLEXIBLE_ARRAY_MEMBER and then making
> the interface look something like this:
>
> extern size_t bloom_estimate(int64 total elems, int work_mem);
> extern void bloom_init(bloom_filter *filter, int64 total_elems, int work_mem);

Yes, that seems quite convenient and is by now an established coding pattern.

I am also wondering whether this patch should consider
81c5e46c490e2426db243eada186995da5bb0ba7 as a way of obtaining
multiple hash values.  I suppose that's probably inferior to what is
already being done on performance grounds, but I'll just throw out a
mention of it here all the same in case it was overlooked or the
relevance not spotted...

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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.