Prevent archive recovery from scanning non-existent WAL files.
authorFujii Masao <[email protected]>
Tue, 7 Apr 2020 15:49:29 +0000 (00:49 +0900)
committerFujii Masao <[email protected]>
Sat, 9 May 2020 03:16:37 +0000 (12:16 +0900)
commit70b5979742f8bb7e5ee83a889989fbe57817cf74
tree8d9d49fccef28596d2f64231364ee3a666529710
parentb37361090e12348bb55d4a51d7f7133216798f0b
Prevent archive recovery from scanning non-existent WAL files.

Previously when there were multiple timelines listed in the history file
of the recovery target timeline, archive recovery searched all of them,
starting from the newest timeline to the oldest one, to find the segment
to read. That is, archive recovery had to continuously fail scanning
the segment until it reached the timeline that the segment belonged to.
These scans for non-existent segment could be harmful on the recovery
performance especially when archival area was located on the remote
storage and each scan could take a long time.

To address the issue, this commit changes archive recovery so that
it skips scanning the timeline that the segment to read doesn't belong to.

Per discussion, back-patch to all supported versions.

Author: Kyotaro Horiguchi, tweaked a bit by Fujii Masao
Reviewed-by: David Steele, Pavel Suderevsky, Grigory Smolkin
Discussion: https://postgr.es/m/16159-f5a34a3a04dc67e0@postgresql.org
Discussion: https://postgr.es/m/20200129.120222.1476610231001551715[email protected]
src/backend/access/transam/xlog.c