mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

hio: Release extension lock before initializing page / pinning VM

Browse Source 
PageInit() while holding the extension lock is unnecessary after 0d1fe9f74e3
started to use RBM_ZERO_AND_LOCK - nobody can look at the new page before we
release the page lock. PageInit() zeroes the page, which isn't that cheap, so
deferring it until after the extension lock is released seems like a good idea.

Doing visibilitymap_pin() while holding the extension lock, introduced in
7db0cd2145f2, looks like an accident. Due to the restrictions on
HEAP_INSERT_FROZEN it's unlikely to be a performance issue, but it still seems
better to move it out.  We also are doing the visibilitymap_pin() while
holding the buffer lock, which will be fixed in a separate commit.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: http://postgr.es/m/419312fd-9255-078c-c3e3-f0525f911d7f@iki.fi
This commit is contained in:
Andres Freund 2023-04-01 17:50:18 -07:00
parent 0070b66fef
commit 14f98e0af9
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/backend/access/heap/hio.c
View File

@ -623,6 +623,13 @@ loop:
*/
buffer = ReadBufferBI(relation, P_NEW, RBM_ZERO_AND_LOCK, bistate);
/*
* Release the file-extension lock; it's now OK for someone else to extend
* the relation some more.
*/
if (needLock)
UnlockRelationForExtension(relation, ExclusiveLock);
/*
* We need to initialize the empty new page. Double-check that it really
* is empty (this should never happen, but if it does we don't want to
@ -647,13 +654,6 @@ loop:
visibilitymap_pin(relation, BufferGetBlockNumber(buffer), vmbuffer);
}
/*
* Release the file-extension lock; it's now OK for someone else to extend
* the relation some more.
*/
if (needLock)
UnlockRelationForExtension(relation, ExclusiveLock);
/*
* Lock the other buffer. It's guaranteed to be of a lower page number
* than the new page. To conform with the deadlock prevent rules, we ought