pgsql: Remove faulty nbtree page deletion assertion. - Mailing list pgsql-committers

From Peter Geoghegan
Subject pgsql: Remove faulty nbtree page deletion assertion.
Date
Msg-id E1xEskU-00000000qa5-0FeK@gemulon.postgresql.org
Whole thread
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Remove faulty nbtree page deletion assertion.

_bt_pagedel only builds a search stack when it needs one to locate the
downlink of the page that it's about to mark half-dead (and when it
doesn't already have one from an earlier sibling deletion that took
place during the same _bt_pagedel call).  _bt_pagedel won't build a
search stack for the page its caller passes whenever it happens to be
one that an earlier interrupted VACUUM left half-dead (since there is no
downlink to remove).  We nevertheless asserted that page deletion could
only build a search stack for that initial caller-passed page.

To fix, remove the assertion, which spuriously failed when a half-dead
leaf page was passed by the _bt_pagedel caller and its right sibling
page was empty/had to be considered for deletion during the same call
(necessitating building a search stack to locate the right sibling's
downlink).

Oversight in commit cd8c73a38, which refactored nbtree page deletion's
INCOMPLETE_SPLIT check.

Author: Peter Geoghegan <pg@bowt.ie>
Reported-by: Iliia Khaprov <i.khaprov@gmail.com>
Discussion: https://postgr.es/m/CAFO+O_p5So4MXwQ1VEcL9+9vGgODu11TTWcYq9RDbxnira8o2w@mail.gmail.com
Backpatch-through: 14

Branch
------
REL_17_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/87e417681653937bd8d01740e1ff3c3c224ba66e

Modified Files
--------------
src/backend/access/nbtree/nbtpage.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)


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