|The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration Guide
by The PostgreSQL Global Development Group
Paperback (6"x9"), 274 pages
RRP £9.95 ($14.95)
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13.2.1 Statistics Collection Configuration
Since collection of statistics adds some overhead to query execution, the system can be configured to collect or not collect information. This is controlled by configuration parameters that are normally set in ‘postgresql.conf’. (See section 4 Server Configuration for details about setting configuration parameters.)
track_counts controls whether
statistics are collected about table and index accesses.
track_functions enables tracking of
usage of user-defined functions.
track_activities enables monitoring
of the current command being executed by any server process.
Normally these parameters are set in ‘postgresql.conf’ so
that they apply to all server processes, but it is possible to turn
them on or off in individual sessions using the
SET command. (To prevent
ordinary users from hiding their activity from the administrator,
only superusers are allowed to change these parameters with
The statistics collector communicates with the backends needing
information (including autovacuum) through temporary files.
These files are stored in the ‘pg_stat_tmp’ subdirectory.
When the postmaster shuts down, a permanent copy of the statistics
data is stored in the ‘global’ subdirectory. For increased
performance, the parameter
be pointed at a RAM-based file system, decreasing physical I/O requirements.
|ISBN 9781906966072||The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration Guide||See the print edition|