Horton

Re: Add contrib/pg_logicalsnapinspect

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: shveta malik <shveta.malik@gmail.com>
Cc: Peter Smith <smithpb2250@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-09-24T16:53:26Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix indentation issue

  2. pg_logicalinspect: Stabilize isolation tests.

  3. Add contrib/pg_logicalinspect.

  4. Move SnapBuild and SnapBuildOnDisk structs to snapshot_internal.h.

Hi,

On Tue, Sep 24, 2024 at 09:15:31AM +0530, shveta malik wrote:
> On Fri, Sep 20, 2024 at 12:22 PM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> >
> >
> > Please find attached v8, that:
> >
> 
> Thank You for the patch. In one of my tests, I noticed that I got
> negative checksum:
> 
> postgres=# SELECT * FROM pg_get_logical_snapshot_meta('0/3481F20');
>    magic    |  checksum  | version
> ------------+------------+---------
>  1369563137 | -266346460 |       6
> 
> But pg_crc32c is uint32. Is it because we are getting it as
> Int32GetDatum(ondisk.checksum) in pg_get_logical_snapshot_meta()?
> Instead should it be UInt32GetDatum?

Thanks for the testing.

As the checksum could be > 2^31 - 1, then v9 (just shared up-thread) changes it
to an int8 in the pg_logicalinspect--1.0.sql file. So, to avoid CI failure on
the 32bit build, then v9 is using Int64GetDatum() instead of UInt32GetDatum().

> Same goes for below:
> values[i++] = Int32GetDatum(ondisk.magic);
> values[i++] = Int32GetDatum(ondisk.magic);

The 2 others field (magic and version) are unlikely to be > 2^31 - 1, so v9 is
making use of UInt32GetDatum() and keep int4 in the sql file.

> We need to recheck the rest of the fields in the info() function as well.

I think that the pg_get_logical_snapshot_info()'s fields are ok (I did spend some
time to debug CI failing on the 32bit build for some on them before submitting v1).

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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