]> granicus.if.org Git - postgresql/commit
Fix past pd_upper write in ginRedoRecompress()
authorAlexander Korotkov <akorotkov@postgresql.org>
Sun, 9 Sep 2018 18:19:29 +0000 (21:19 +0300)
committerAlexander Korotkov <akorotkov@postgresql.org>
Sun, 9 Sep 2018 18:44:58 +0000 (21:44 +0300)
commite950c6c9db0ee54c7693bfaf73ea766021b404e3
tree76cd420994868abcf3be982124b657f8c874a4e3
parent0254aa83b57abb4e971f6b225cc4678c782fdf51
Fix past pd_upper write in ginRedoRecompress()

ginRedoRecompress() replays actions over compressed segments of posting list
in-place.  However, it might lead to write past pg_upper, because intermediate
state during playing the changes can take more space than both original state
and final state.  This commit fixes that by refuse from in-place modification.
Instead page tail is copied once modification is started, and then it's used
as the source of original segments.  Backpatch to 9.4 where posting list
compression was introduced.

Reported-by: Sivasubramanian Ramasubramanian
Discussion: https://postgr.es/m/1536091151804.6588%40amazon.com
Author: Alexander Korotkov based on patch from and ideas by Sivasubramanian Ramasubramanian
Review: Sivasubramanian Ramasubramanian
Backpatch-through: 9.4
src/backend/access/gin/ginxlog.c