Re: [Patch] ALTER SYSTEM READ ONLY

Amul Sul <sulamul@gmail.com>

View thread View on postgr.es

From: Amul Sul <sulamul@gmail.com>

To: Robert Haas <robertmhaas@gmail.com>

Cc: Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2020-11-23T06:36:45Z

Lists: pgsql-hackers

Attachments

v11-0004-Implement-ALTER-SYSTEM-READ-ONLY-using-global-ba.patch (application/octet-stream) patch v11-0004
v11-0005-Error-or-Assert-before-START_CRIT_SECTION-for-WA.patch (application/octet-stream) patch v11-0005
v11-0002-Test-module-for-barriers.-NOT-FOR-COMMIT.patch (application/octet-stream) patch v11-0002
v11-0001-Allow-for-error-or-refusal-while-absorbing-barri.patch (application/octet-stream) patch v11-0001
v11-0006-WIP-Documentation.patch (application/octet-stream) patch v11-0006
v11-0003-Add-alter-system-read-only-write-syntax.patch (application/octet-stream) patch v11-0003

On Fri, Nov 20, 2020 at 11:13 PM Amul Sul <sulamul@gmail.com> wrote:
>
> On Fri, 20 Nov 2020 at 9:53 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>>
>> On Thu, Oct 8, 2020 at 6:23 AM Amul Sul <sulamul@gmail.com> wrote:
>> > On a quick look at the latest 0001 patch, the following hunk to reset leftover
>> > flags seems to be unnecessary:
>> >
>> > + /*
>> > + * If some barrier types were not successfully absorbed, we will have
>> > + * to try again later.
>> > + */
>> > + if (!success)
>> > + {
>> > + ResetProcSignalBarrierBits(flags);
>> > + return;
>> > + }
>> >
>> > When the ProcessBarrierPlaceholder() function returns false without an error,
>> > that barrier flag gets reset within the while loop.  The case when it has an
>> > error, the rest of the flags get reset in the catch block.  Correct me if I am
>> > missing something here.
>>
>> Good catch. I think you're right. Do you want to update accordingly?
>
>
> Sure, Ill update that. Thanks for the confirmation.
>

Attached is the updated version where unnecessary ResetProcSignalBarrierBits()
call in 0001 patch is removed. The rest of the patches are unchanged, thanks.

>>
>> Andres, do you like the new loop better?
>>

Regards,
Amul

Commits

Initialize variable to placate compiler.
- a030a0c5ccb1 15.0 landed
StartupXLOG: Don't repeatedly disable/enable local xlog insertion.
- 18e0913a4203 15.0 landed
StartupXLOG: Call CleanupAfterArchiveRecovery after XLogReportParameters.
- a75dbf7f9ee6 15.0 landed
Postpone some end-of-recovery operations related to allowing WAL.
- 811051c2e7af 15.0 landed
Refactor some end-of-recovery code out of StartupXLOG().
- 6df1543abfed 15.0 landed
Re-enable contrib/bloom's TAP tests.
- 7d1aa6bf1c27 15.0 cited
Remove unnecessary call to ReadCheckpointRecord().
- 1d919de5eb3f 15.0 cited
Allow for error or refusal while absorbing a ProcSignalBarrier.
- a3ed4d1efe9f 14.0 landed
Add comment to explain an unused function parameter
- 101f903e51f5 14.0 cited
Extend the ProcSignal mechanism to support barriers.
- 16a4e4aecd47 13.0 cited
At promotion, don't leave behind a partial segment on the old timeline.
- 7cbee7c0a1db 9.5.0 cited