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Re: increasing the default WAL segment size

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2016-08-25T03:26:51Z
Lists: pgsql-hackers 
On Wed, Aug 24, 2016 at 10:54 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-08-24 22:33:49 -0400, Tom Lane wrote:
>> > Possibly it would make sense for this to be configurable at initdb
>> > time instead of requiring a recompile;
>>
>> ... but I think this is just folly.  You'd have to do major amounts
>> of work to keep, eg, slave servers on the same page as the master
>> about what the segment size is.
>
> Don't think it'd actually be all that complicated, we already verify
> the compatibility of some things.  But I'm doubtful it's worth it, and
> I'm also rather doubtful that it's actually without overhead.

Really?  Where do you think the overhead would come from?  What sort
of test would you run to try to detect it?

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

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Make WAL segment size configurable at initdb time.

  2. Perform only one ReadControlFile() during startup.

  3. Introduce BYTES unit for GUCs.

  4. Remove useless duplicate inclusions of system header files.

  5. Refactor other replication commands to use DestRemoteSimple.

  6. Add a SHOW command to the replication command language.

  7. Add a new DestReceiver for printing tuples without catalog access.

  8. Support fls().

  9. Extend yesterday's patch making BLCKSZ and RELSEG_SIZE configurable to also

  10. Commit the reasonably uncontroversial parts of J.R. Nield's PITR patch, to

  11. XLOG (also known as WAL -:)) Bootstrap/Startup/Shutdown.

  12. Transaction log manager core code.