On Mon, Sep 5, 2016 at 9:33 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > USE_CONTENT_LOCK on my windows box, you can try by commenting that as > well, if it works for you). So, in short we have to compare three > approaches here. > > 1) Group mode to reduce CLOGControlLock contention > 2) Use granular locking model > 3) Use atomic operations
I have tested performance with approach 1 and approach 2. 1. Transaction (script.sql): I have used below transaction to run my bench mark, We can argue that this may not be an ideal workload, but I tested this to put more load on ClogControlLock during commit transaction. ----------- \set aid random (1,30000000) \set tid random (1,3000) BEGIN; SELECT abalance FROM pgbench_accounts WHERE aid = :aid for UPDATE; SAVEPOINT s1; SELECT tbalance FROM pgbench_tellers WHERE tid = :tid for UPDATE; SAVEPOINT s2; SELECT abalance FROM pgbench_accounts WHERE aid = :aid for UPDATE; END; ----------- 2. Results ./pgbench -c $threads -j $threads -T 10 -M prepared postgres -f script.sql scale factor: 300 Clients head(tps) grouplock(tps) granular(tps) ------- --------- ---------- ------- 128 29367 39326 37421 180 29777 37810 36469 256 28523 37418 35882 grouplock --> 1) Group mode to reduce CLOGControlLock contention granular --> 2) Use granular locking model I will test with 3rd approach also, whenever I get time. 3. Summary: 1. I can see on head we are gaining almost ~30 % performance at higher client count (128 and beyond). 2. group lock is ~5% better compared to granular lock. -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
