Horton

Re: BUG #16663: DROP INDEX did not free up disk space: idle connection hold file marked as deleted

Pavel Borisov <pashkin.elfe@gmail.com>

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From: Pavel Borisov <pashkin.elfe@gmail.com>
To: Neil Chen <carpenter.nail.cz@gmail.com>
Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>
Date: 2020-11-19T15:54:54Z
Lists: pgsql-bugs, pgsql-hackers 
>
> One thing that doesn't matter is that the modify here seems unnecessary,
> right?
>
> > mdunlinkfork(RelFileNodeBackend rnode, ForkNumber forkNum, bool isRedo)
> > {
> > char     *path;
> > -     int                     ret;
> > +     int                     ret = 0;
> > path = relpath(rnode, forkNum


I suppose it is indeed necessary as otherwise the result of the comparison
is not defined in case of 'else' block in the mdunlinkfork() :
346     else
347     {
348         /* Prevent other backends' fds from holding on to the disk
space */
349         do_truncate(path);
.....
356      * Delete any additional segments.
357      */
358     if (ret >= 0)
----------^^^^^^^

-- 
Best regards,
Pavel Borisov

Postgres Professional: http://postgrespro.com <http://www.postgrespro.com>

Commits

  1. Use truncate(2) where appropriate.

  2. Free disk space for dropped relations on commit.

  3. Rename the "point is strictly above/below point" comparison operators.