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Re: increasing the default WAL segment size

Beena Emerson <memissemerson@gmail.com>

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From: Beena Emerson <memissemerson@gmail.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-04-06T23:38:15Z
Lists: pgsql-hackers 
On Fri, Apr 7, 2017 at 2:35 AM, Tomas Vondra <tomas.vondra@2ndquadrant.com>
wrote:

> On 04/06/2017 08:33 PM, David Steele wrote:
>>
>>
>> I'm in favor of 16,64,256,1024.
>>
>>
> I don't see a particular reason for this, TBH. The sweet spots will be
> likely dependent hardware / OS configuration etc. Assuming there actually
> are sweet spots - no one demonstrated that yet.
>
> Also, I don't see how supporting additional WAL sizes increases chance of
> incompatibility. We already allow that, so either the tools (e.g. backup
> solutions) assume WAL segments are always 16MB (in which case are
> essentially broken) or support valid file sizes (in which case they should
> have no issues with the new ones).
>
> If we're going to do this, I'm in favor of deciding some reasonable upper
> limit (say, 1GB or 2GB sounds good), and allowing all 2^n values up to that
> limit.


I think the majority consensus is to use all valid values. Since 1GB is
what we have finalized as the upper limit, lets continue with that for now.


-- 

Beena Emerson

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.