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Re: increasing the default WAL segment size

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Robert Haas <robertmhaas@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2016-08-25T03:02:41Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2016-08-24 22:33:49 -0400, Tom Lane wrote:
>> ... 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.

My point is basically that it'll introduce failure modes that we don't
currently concern ourselves with.  Yes, you can do configure
--with-wal-segsize, but it's on your own head whether the resulting build
will interoperate with anything else --- and I'm quite sure nobody tests,
eg, walsender or walreceiver to see if they fail sanely in such cases.
I don't think we'd get to take such a laissez-faire position with respect
to an initdb option.

			regards, tom lane

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.