Horton

Re: [Patch] ALTER SYSTEM READ ONLY

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Amul Sul <sulamul@gmail.com>
Cc: Jaime Casanova <jcasanov@systemguards.com.ec>, Rushabh Lathia <rushabh.lathia@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Prabhat Sahu <prabhat.sahu@enterprisedb.com>
Date: 2021-10-25T14:45:21Z
Lists: pgsql-hackers 
On Mon, Oct 25, 2021 at 3:05 AM Amul Sul <sulamul@gmail.com> wrote:
> Ok, did the same in the attached 0001 patch.
>
> There is no harm in calling LocalSetXLogInsertAllowed() calling
> multiple times, but the problem I can see is that with this patch user
> is allowed to call LocalSetXLogInsertAllowed() at the time it is
> supposed not to be called e.g. when LocalXLogInsertAllowed = 0;
> WAL writes are explicitly disabled.

I've pushed 0001 and 0002 but I reversed the order of them and made a
few other edits.

I don't really see the issue you mention here as a problem. There's
only one place where we set LocalXLogInsertAllowed = 0, and I don't
know that we'll ever have another one.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

  1. Initialize variable to placate compiler.

  2. StartupXLOG: Don't repeatedly disable/enable local xlog insertion.

  3. StartupXLOG: Call CleanupAfterArchiveRecovery after XLogReportParameters.

  4. Postpone some end-of-recovery operations related to allowing WAL.

  5. Refactor some end-of-recovery code out of StartupXLOG().

  6. Re-enable contrib/bloom's TAP tests.

  7. Remove unnecessary call to ReadCheckpointRecord().

  8. Allow for error or refusal while absorbing a ProcSignalBarrier.

  9. Add comment to explain an unused function parameter

  10. Extend the ProcSignal mechanism to support barriers.

  11. At promotion, don't leave behind a partial segment on the old timeline.