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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: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Stephen Frost <sfrost@snowman.net>, David Steele <david@pgmasters.net>, tushar <tushar.ahuja@enterprisedb.com>, Prabhat Sahu <prabhat.sahu@enterprisedb.com>, Ashutosh Sharma <ashu.coek88@gmail.com>, Jim Nasby <Jim.Nasby@bluetreble.com>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>
Date: 2017-04-05T10:04:25Z
Lists: pgsql-hackers 
Hello,

On Wed, Apr 5, 2017 at 9:29 AM, Peter Eisentraut <
peter.eisentraut@2ndquadrant.com> wrote:

> On 4/4/17 22:47, Amit Kapila wrote:
> >> Committed first part to allow internal representation change (only).
> >>
> >> No commitment yet to increasing wal-segsize in the way this patch has
> it.
> >>
> >
> > What part of patch you don't like and do you have any suggestions to
> > improve the same?
>
> I think there are still some questions and disagreements about how it
> should behave.
>

The  WALfilename - LSN mapping disruption for higher values you mean? Is
there anything else I have missed?


>
> I suggest the next step is to dial up the allowed segment size in
> configure and run some tests about what a reasonable maximum value could
> be.  I did a little bit of that, but somewhere around 256 MB, things got
> really slow.
>

Would it be better if just increase the limit to 128MB for now?
In next we can change the WAL file name format and expand the range?

-- 

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.