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| author | Peter Geoghegan <pg@bowt.ie> | 2020-04-25 14:17:02 -0700 |
|---|---|---|
| committer | Peter Geoghegan <pg@bowt.ie> | 2020-04-25 14:17:02 -0700 |
| commit | fa7ff642c22ceccad869af5add00c2661d4d091e (patch) | |
| tree | a797b4c7b0818c64c5e1143f6e222beaf2c74fa7 /src/backend/access/transam/xlog.c | |
| parent | f246ea3b2a5e0b75e44f0f18157c4b5e10b5547f (diff) | |
| download | postgresql-fa7ff642c22ceccad869af5add00c2661d4d091e.tar.gz postgresql-fa7ff642c22ceccad869af5add00c2661d4d091e.zip | |
Fix minor nbtree page deletion buffer lock issue.
Avoid accessing the deletion target page's special area during nbtree
page deletion at a point where there is no buffer lock held. This issue
was detected by a patch that extends Valgrind's memcheck tool to mark
nbtree pages that are unsafe to access (due to not having a buffer lock
or buffer pin) as NOACCESS.
We do hold a buffer pin at this point, and only access the special area,
so the old approach was safe. Even still, it seems like a good idea to
tighten up the rules in this area. There is no reason to not simply
insist on always holding a buffer lock (not just a pin) when accessing
nbtree pages.
Update some related comments in passing.
Discussion: https://postgr.es/m/CAH2-WzkLgyN3zBvRZ1pkNJThC=xi_0gpWRUb_45eexLH1+k2_Q@mail.gmail.com
Diffstat (limited to 'src/backend/access/transam/xlog.c')
0 files changed, 0 insertions, 0 deletions