Horton

Re: Avoid erroring out when unable to remove or parse logical rewrite files to save checkpoint work

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, "Bossart, Nathan" <bossartn@amazon.com>, Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-17T07:09:26Z
Lists: pgsql-hackers

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On Wed, Aug 17, 2022 at 2:02 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
>
> On Wed, Aug 10, 2022 at 03:28:25PM +0530, Bharath Rupireddy wrote:
> >               snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
> > -             if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
> > +             if (get_dirent_type(path, mapping_de, false, LOG) != PGFILETYPE_REG)
> >                       continue;
>
> Previously, failure to lstat() wouldn't lead to skipping the entry.  With
> this patch, a failure to determine the file type will cause the entry to be
> skipped.  This might be okay in some places (e.g., CheckPointSnapBuild())
> but not in others.  For example, in CheckPointLogicalRewriteHeap(), this
> could cause us to skip fsync-ing a file due to a get_dirent_type() failure,
> which seems bad.

Hm. I corrected it in the v16 patch, please review.

-- 
Bharath Rupireddy
RDS Open Source Databases: https://aws.amazon.com/rds/postgresql/

Commits

  1. Expand the use of get_dirent_type(), shaving a few calls to stat()/lstat()

  2. fsync pg_logical/mappings in CheckPointLogicalRewriteHeap().

  3. Introduce logical decoding.