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Re: increasing the default WAL segment size

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: David Steele <david@pgmasters.net>, Robert Haas <robertmhaas@gmail.com>, Beena Emerson <memissemerson@gmail.com>, tushar <tushar.ahuja@enterprisedb.com>, Prabhat Sahu <prabhat.sahu@enterprisedb.com>, Ashutosh Sharma <ashu.coek88@gmail.com>, Jim Nasby <Jim.Nasby@bluetreble.com>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-03-25T16:30:11Z
Lists: pgsql-hackers 
Peter,

* Peter Eisentraut (peter.eisentraut@2ndquadrant.com) wrote:
> On 3/24/17 19:13, David Steele wrote:
> > Behavior for the current default of 16MB is unchanged, and all other 
> > sizes go through a logical progression.
> 
> Just at a glance, without analyzing the math behind it, this scheme
> seems super confusing.

Compared to:

1GB:
000000010000000000000001
000000010000000000000002
000000010000000000000003
000000010000000100000000

...?

Having the naming no longer match the LSN and also, seemingly, jump
randomly, strikes me as very confusing.  At least with the LSN-based
approach, we aren't jumping randomly but exactly in-line with what the
starting LSN of the file is, and always by the same amount (in hex).

Thanks!

Stephen

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.