Re: [HACKERS] Many processes blocked at ProcArrayLock
Xiaoyulei wrote: I put all the stack in attachment. Not sure that this is really all that useful. At least I don't have the patience to examine all this, and I'm not sure it contains the needed info in the first place. If you were to ensure your build is using -fno-omit-frame-pointer in cflags and then used perf record -a -g while the test runs and perf report -g once it's finished, you'd get a useful profile that would show who is acquiring the problematic lock and why. -- Álvaro Herrerahttp://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Many processes blocked at ProcArrayLock
Test configuration: Hardware: 4P intel server, 60 core 120 hard thread. Memory:512G SSD:2.4T PG: max_connections = 160 # (change requires restart) shared_buffers = 32GB work_mem = 128MB maintenance_work_mem = 32MB bgwriter_delay = 100ms # 10-1ms between rounds bgwriter_lru_maxpages = 200 # 0-1000 max buffers written/round bgwriter_lru_multiplier = 2.0 # 0-10.0 multipler on buffers scanned/round wal_level = minimal # minimal, archive, or hot_standby wal_buffers = 256MB # min 32kB, -1 sets based on shared_buffers autovacuum = off checkpoint_timeout=60min checkpoint_segments = 1000 archive_mode = off synchronous_commit = off fsync = off full_page_writes = off We use tpcc and pgbench to test postgresql 9.4beat2 performance. And we found the tps/tpmc could not increase with the terminal increase. The detail information is in attachment. Many processes is blocked, I dump the call stack, and found these processes is blocked at: ProcArrayLock. 60% processes is blocked in ProcArrayEndTransaction with ProcArrayLock EXCLUSIVE, 20% is in GetSnapshotData with ProcArrayLock SHARED. Others locks like XLogFlush and WALInsertLock are not very heavy. Is there any way we solve this problem? -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Many processes blocked at ProcArrayLock
On Tue, Dec 2, 2014 at 5:07 PM, Xiaoyulei xiaoyu...@huawei.com wrote: Test configuration: Hardware: 4P intel server, 60 core 120 hard thread. Memory:512G SSD:2.4T PG: max_connections = 160 # (change requires restart) shared_buffers = 32GB work_mem = 128MB maintenance_work_mem = 32MB bgwriter_delay = 100ms # 10-1ms between rounds bgwriter_lru_maxpages = 200 # 0-1000 max buffers written/round bgwriter_lru_multiplier = 2.0 # 0-10.0 multipler on buffers scanned/round wal_level = minimal # minimal, archive, or hot_standby wal_buffers = 256MB # min 32kB, -1 sets based on shared_buffers autovacuum = off checkpoint_timeout=60min checkpoint_segments = 1000 archive_mode = off synchronous_commit = off fsync = off full_page_writes = off We use tpcc and pgbench to test postgresql 9.4beat2 performance. And we found the tps/tpmc could not increase with the terminal increase. The detail information is in attachment. Many processes is blocked, I dump the call stack, and found these processes is blocked at: ProcArrayLock. 60% processes is blocked in ProcArrayEndTransaction with ProcArrayLock EXCLUSIVE, 20% is in GetSnapshotData with ProcArrayLock SHARED. Others locks like XLogFlush and WALInsertLock are not very heavy. Is there any way we solve this problem? Providing complete backtraces showing in which code paths those processes are blocked would help better in understand what may be going on. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
