We upgraded from Ubuntu 11.04 to Ubuntu 12.04 and almost immediately obeserved increased CPU usage and significantly higher load average on our database server.
At the time we were on Postgres 9.0.5. We decided to upgrade to Postgres 9.2 to see if that resolves the issue, but unfortunately it did not.
Just for illustration purposes, below are a few links to cpu and load graphs pre and post upgrade.
We also tried tweaking kernel parameters as mentioned here - http://www.postgresql.org/message-id/50E4AAB1.email@example.com, but have not seen any improvement.
Any advice on how to trace what could be causing the change in CPU usage and load average is appreciated.
Our postgres version is:
PostgreSQL 9.2.2 on x86_64-unknown-linux-gnu, compiled by gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3, 64-bit
Linux ip-10-189-175-25 3.2.0-37-virtual #58-Ubuntu SMP Thu Jan 24 15:48:03 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
Hardware (this an Amazon Ec2 High memory quadruple extra large instance):
8 core Intel(R) Xeon(R) CPU E5-2665 0 @ 2.40GHz
68 GB RAM
RAID10 with 8 drives using xfs
Drives are EBS with provisioned IOPS, with 1000 iops each
archive_command = rsync -a %p slave:/var/lib/postgresql/replication_load/%f
archive_mode = on
checkpoint_completion_target = 0.9
checkpoint_segments = 64
checkpoint_timeout = 30min
default_text_search_config = pg_catalog.english
external_pid_file = /var/run/postgresql/9.2-main.pid
lc_messages = en_US.UTF-8
lc_monetary = en_US.UTF-8
lc_numeric = en_US.UTF-8
lc_time = en_US.UTF-8
listen_addresses = *
log_line_prefix = %t [%p]: [%l-1]
pgsql-performance by date
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