Subject High "Mutex wait" value, after increase in "Hash Slots" to 90001
Author Leyne, Sean
We have a client with 320GB database (running FB CS v2.5) reporting performance issues, while we are investigating possible application sources, I have been reviewing their Firebird config.
Yesterday, I ran fb_lock_print to check on the database and found a “Mutex wait” value of 20.9%, which I knew that a “bad thing”.  So, I increased (by 50%) the “Hash slots” value from 60011 to 90001.
Now, today, I checked the lock print values again, and got even worse numbers!!!
                Version: 145, Active owner:      0, Length: 67108864, Used: 32723368
                Flags: 0x0001
                Enqs: 712175161, Converts: 9327661, Rejects: 1440802, Blocks: 15963765
                Deadlock scans:      9, Deadlocks:      0, Scan interval:  10
                Acquires: 1133127873, Acquire blocks: 256464312, Spin count:   0
                Mutex wait: 22.6%
                Hash slots: 90001, Hash lengths (min/avg/max):    0/   0/   5
                Remove node:      0, Insert queue:      0, Insert prior:      0
                Owners (288):   forward: 732776, backward: 29775680
                Free owners (400):      forward: 9817904, backward: 9548560
                Free locks (28162):     forward: 20344528, backward: 18378944
                Free requests (293517): forward: 7727280, backward: 23127520
                Lock Ordering: Enabled
Any suggestions on how I can improve the numbers?
Thanks in advance