Hi, On 23 August 2012 23:37, Bill Moran <wmoran@xxxxxxxxxxxxxxxxx> wrote: > > And the advice I have along those lines is to establish now what > constitutes unacceptable performance, and put some sort of monitoring > and tracking in place to know what your performance degradation looks > like and predict when you'll have to react. For example, a MRTG > graph that runs an experimental query once a day during off hours and > graphs the time it takes vs. the # of rows in the table will prove > a valuable tool that can sometimes predict exactly when you'll have > to change things before it becomes a problem. Other tricks work as > well, such as having the application send an email any time a process > takes more than 50% of the allowable maximum time. > I like to use APDEX (http://apdex.org/specs.html). You can change your database to all time for all statements and then calculate APDEX score based on last N log entries (> 10). APDEX score is weighted score based on number of datapoints within three zones: 0...T Satisfied Zone T..F (=4*T) Tolerating Zone 4T... Frustrated Zone you can choose T (or F; then T = F/4) i.e. under normal circumstances all queries should finish under 20ms (T = 20ms, F = 4T = 80ms). Apdex score is: score = (Satisfied count + Tolerating count / 2) / Total samples You can get this number, for example, every minute and plot it using Ganglia / MRTG / ... -- Ondrej Ivanic (ondrej.ivanic@xxxxxxxxx) -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
