On Wed, May 23, 2012 at 5:29 AM, Andrzej Krawiec <a.kraw...@focustelecom.pl> wrote: > Cannot strace or gdb on a production system under heavy load (about 100 > transactions per second). > It's in kernel space not user, so we are unable to anything at this > particular moment (sometimes even the ssh connection seems to hang for a > while). > We suspect neither autovacuum (although suspected primarily) nor regular > backend. It is system time. The question is: what's the reasone for that? > We've dug through system and postgres logs, cleared out most of the long > query problems, idle in transaction, optimized queries, vacuumed, reindexed > and such. > For a while it seemed like the particular kernel version is causing majority > of problems. We have downgraded to 2.6.32.-71.29.1.el6.x86_64 and those > problems went mostly! away. For few days we had no situations, but it > happened again.
perf can tell you about problems in kernel-space, but I'm not sure it exists that far back. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
