Horton

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

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From: PG Bug reporting form <noreply@postgresql.org>
To: pgsql-bugs@lists.postgresql.org
Cc: denis.patron@previnet.it
Date: 2020-10-09T13:24:15Z
Lists: pgsql-bugs, pgsql-hackers 
The following bug has been logged on the website:

Bug reference:      16663
Logged by:          Denis Patron
Email address:      denis.patron@previnet.it
PostgreSQL version: 11.9
Operating system:   CentOS 7
Description:        

I have an index, which at the file system level, is made up of multiple
segments (file: <id>.1, <id>.2 ecc). When I DROP INDEX, the index is dropped
in Postgresql but at the file system level, the segments are marked as
"deleted". if I check with the lsof command, I see that the segments are in
use from an idle connection. This does not happen if the index is formed by
only one segment (in my case <1Gb). How can I prevent this?
thanks

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.