On 12/11/2024 03:16, Fujii Masao wrote:
Hi,
I've identified some opportunities to optimize
FastPathTransferRelationLocks(), which transfers locks with a
specific lock tag from per-backend fast- path arrays to the shared
hash table. The attached patch includes these enhancements.
Currently, FastPathTransferRelationLocks() recalculates the fast-
path group on each loop iteration, even though it stays the same.
This patch updates the function to calculate the group once and
reuse it, improving efficiency.
Makes sense. GetLockConflicts() has similar code, the same optimizations
would apply there too.
The patch also extends the function's logic to skip not only
backends from a different database but also backends with pid=0
(which don’t hold fast-path locks) and groups with no registered
fast-path locks.
Since MyProc->pid is reset to 0 when a backend exits but MyProc-
>databaseId remains set, checking only databaseId isn’t enough.
Backends with pid=0 also should be skipped.
Hmm, a PGPROC entry that's not in use would also have
proc->fpLockBits[group] == 0, so I'm not sure if the check for proc->pid
== 0 is necessary.
And perhaps we should start clearing databaseid on backend exit.
--
Heikki Linnakangas
Neon (https://neon.tech)
