pgsql: Fix two bugs in WAL-logging of GIN pending-list pages. - Mailing list pgsql-committers

From Heikki Linnakangas
Subject pgsql: Fix two bugs in WAL-logging of GIN pending-list pages.
Date
Msg-id E1Wembt-000225-E3@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Fix two bugs in WAL-logging of GIN pending-list pages.

In writeListPage, never take a full-page image of the page, because we
have all the information required to re-initialize in the WAL record
anyway. Before this fix, a full-page image was always generated, unless
full_page_writes=off, because when the page is initialized its LSN is
always 0. In stable-branches, keep the code to restore the backup blocks
if they exist, in case that the WAL is generated with an older minor
version, but in master Assert that there are no full-page images.

In the redo routine, add missing "off++". Otherwise the tuples are added
to the page in reverse order. That happens to be harmless because we
always scan and remove all the tuples together, but it was clearly wrong.
Also, it was masked by the first bug unless full_page_writes=off, because
the page was always restored from a full-page image.

Backpatch to all supported versions.

Branch
------
REL8_4_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/be249420414e3d2a613aa1f295656a2a820b7941

Modified Files
--------------
src/backend/access/gin/ginfast.c |    3 +--
src/backend/access/gin/ginxlog.c |    6 ++++++
2 files changed, 7 insertions(+), 2 deletions(-)


pgsql-committers by date:

Previous
From: Robert Haas
Date:
Subject: pgsql: Minor fixes for ALTER TABLE documentation.
Next
From: Heikki Linnakangas
Date:
Subject: pgsql: Fix two bugs in WAL-logging of GIN pending-list pages.