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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: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Josh Berkus <josh@agliodbs.com>, Magnus Hagander <magnus@hagander.net>, Simon Riggs <simon@2ndquadrant.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2016-08-25T19:53:14Z
Lists: pgsql-hackers 
On Thu, Aug 25, 2016 at 3:21 PM, Alvaro Herrera
<alvherre@2ndquadrant.com> wrote:
> Yeah, and it's also related to the point Josh Berkus was making about
> clusters with little activity.

Right.

> Does it work to set the minimum to one WAL segment, i.e. 64MB?  guc.c
> has a hardcoded minimum of 2, but I couldn't find an explanation for it.

Well, I think that when you overrun the end of one segment, you're
never going to be able to wrap around to the start of the same
segment; you're going to get sucked into needing another file.

-- 
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.