Horton

Re: Performance Improvement by reducing WAL for Update Operation

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andres Freund <andres@2ndquadrant.com>
Cc: Heikki Linnakangas <hlinnakangas@vmware.com>, Amit Kapila <amit.kapila16@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Mike Blackwell <mike.blackwell@rrd.com>, Bruce Momjian <bruce@momjian.us>, Peter Geoghegan <pg@heroku.com>, Claudio Freire <klaussfreire@gmail.com>
Date: 2014-03-03T15:53:04Z
Lists: pgsql-hackers 
On Mon, Mar 3, 2014 at 10:38 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> On 2014-03-03 10:35:03 -0500, Robert Haas wrote:
>> On Mon, Mar 3, 2014 at 9:57 AM, Andres Freund <andres@2ndquadrant.com> wrote:
>> > Hm, I think all it needs to do disable delta encoding if
>> > need_tuple_data (which is dependent on wal_level=logical).
>>
>> Why does it need to do that?  The logical decoding stuff should be
>> able to reverse out the delta encoding.
>
> Against what should it perform the delta? Unless I misunderstand how the
> patch works, it computes the delta against the old tuple in the heap
> page?

Oh, maybe I need more caffeine.

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

Commits

  1. Flush stderr and stdout in isolation tester.