On Tue, Sep 1, 2015 at 2:04 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > Memory bandwidth, for example. It's quite difficult to spot, because the > intuition is that memory is fast, but thanks to improvements in storage (and > stagnation in RAM bandwidth), this is becoming a significant issue.
I'd appreciate any tips on how to spot problems of this type. But it's my impression that perf, top, vmstat, and other Linux performance tools will count time spent waiting for memory as CPU time, not idle time. If that's correct, that wouldn't explain workloads where CPU utilization doesn't reach 100%. Rather, it would show up as CPU time hitting 100% while tps remains low. > Process-management overhead is another thing we tend to ignore, but once you > get to many processes all willing to work at the same time, you need to > account for that. Any tips on spotting problems in that area? Thanks, -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
