Thread: pgsql: Fix another minor page deletion buffer lock issue.
Fix another minor page deletion buffer lock issue. Avoid accessing the leaf page's top parent tuple without a buffer lock held during the second phase of nbtree page deletion. The old approach was safe, though only because VACUUM never drops its buffer pin (and because only VACUUM itself can modify a half-dead page). Even still, it seems like a good idea to be strict here. Tighten things up by copying the top parent page's block number to a local variable before releasing the buffer lock on the leaf page -- not after. This is a follow-up to commit fa7ff642, which fixed a similar issue in the first phase of nbtree page deletion. Update some related comments in passing. Discussion: https://postgr.es/m/CAH2-WzkLgyN3zBvRZ1pkNJThC=xi_0gpWRUb_45eexLH1+k2_Q@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/7154aa16a64dd4afc2cbf02e7ce86dc6711a1087 Modified Files -------------- src/backend/access/nbtree/nbtpage.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-)