'\"macro stdmacro
.\"
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.TH PMDAPOSTGRESQL 1 "PCP" "Performance Co-Pilot"
.SH NAME
\f3pmdapostgresql\f1 \- PostgreSQL database PMDA
.SH DESCRIPTION
\f3pmdapostgresql\f1 is a Performance Co-Pilot \s-1PMDA\s0 which extracts
live performance data from a running PostgreSQL database server.
.PP
Many of the staticstics available from a PostgreSQL server may not
be enabled by default.
Refer to the online documentation at
.I https://www.postgresql.org/docs/current/static/monitoring-stats.html
which describes each of the available parameters related to statistics
collection and how to enable them.
.SH INSTALLATION
\f3pmdapostgresql\f1 uses a configuration file from \&\f(CW$PCP_PMDAS_DIR\fR/postgresql/postgresql.conf
.PP
This file currently contains only one section
.B [authentication]
which specifies values for the following default settings:
.IP "\(bu" 4
host \- hostname, [default: 'local']
.IP "\(bu" 4
port \- port number, [default: '5432']
.IP "\(bu" 4
dbname \- database name, [default: 'postgres']
.IP "\(bu" 4
username \- username to run as and to connect to the database [default: 'postgres']
.IP "\(bu" 4
password \- password to connect to the database [default: 'password']
.IP "\(bu" 4
osuser \- operating system user the PMDA runs as [default: not set]
.PD
.PP
The defaults (as above) will result in the PMDA running as the
current user, using a UNIX domain socket connection to the PostgreSQL server on the localhost.
If
.B osuser
is not specified in the configuration file, the PMDA will run as the current user.
A host specification of "local" will use a UNIX domain socket, which uses peer authentication,
see comments in the
.B pg_hba.conf
file.
In this case, the
.B osuser
setting should probably be set to
.BR postgres .
.PP
It is generally not necessary to alter the default configuration file for monitoring
the local PostgreSQL server instance with a default server configuration.
Note the port number is required even for a UNIX domain
connection because it's used as the socket filename by the server.
.PP
Once this is setup, you can access the names and values for the
postgresql performance metrics by doing the following as root:
.PP
      # cd $PCP_PMDAS_DIR/postgresql
.br
      # ./Install
.PP
To uninstall, do the following as root:
.PP
      # cd $PCP_PMDAS_DIR/postgresql
.br
      # ./Remove
.PP
\fBpmdapostgresql\fR is launched by \fIpmcd\fR(1) and should never be executed 
directly. The Install and Remove scripts notify \fIpmcd\fR(1) when the 
agent is installed or removed.
.PP
\fBpmdapostgresql\fR will automatically attempt to reconnect to the PostgreSQL server
if it's connection is lost - e.g. if the PostgreSQL service is restarted.
.SH "SUPPORTED VERSIONS"
\fBpmdapostgresql\fR has been tested and verified with
PostgreSQL server version
.B 10.2
and earlier.
Later versions will probably also work correctly because the PMDA
probes the various performance tables on start-up to determine the
column ordering.
It also tolerates missing or renamed tables and/or columns.
.SH FILES
.IP "\fB$PCP_PMDAS_DIR/postgresql/pmdapostgresql.conf\f1"
configuration file for \fBpmdapostgresql\fR
.IP "\fB$PCP_PMDAS_DIR/postgresql/Install\fR" 4 
installation script for the \fBpmdapostgresql\fR agent 
.IP "\fB$PCP_PMDAS_DIR/postgresql/Remove\fR" 4 
undo installation script for the \fBpmdapostgresql\fR agent 
.IP "\fB$PCP_LOG_DIR/pmcd/postgresql.log\fR" 4 
default log file for error messages from \fBpmdapostgresql\fR 
.PP
Note the usual/default value for \fB$PCP_PMDAS_DIR\fP is
.B /var/lib/pcp/pmdas
and the default for \fB$PCP_LOG_DIR\fP is
.B /var/log/pcp
but these settings are platform dependent.
.PD
.SH PCP ENVIRONMENT
Environment variables with the prefix \fBPCP_\fR are used to parameterize
the file and directory names used by \fBPCP\fR. On each installation, the
file \fB/etc/pcp.conf\fR contains the local values for these variables. 
The \fB$PCP_CONF\fR variable may be used to specify an alternative 
configuration file, as described in \fIpcp.conf\fR(5).
.SH SEE ALSO
.BR PCPIntro (1),
.BR PMCD (1)
and
.B https://www.postgresql.org/docs/current/static/monitoring-stats.html