Example

 [postgres_*]
    user postgres
    env.PGUSER postgres
    env.PGPORT 5433
  [postgres_connections_ALL]
    env.warning :450
    env.critical :500

Initialization

 use Munin::Plugin::Pgsql;
 my $pg = Munin::Plugin::Pgsql->new(
    parameter=>value,
    parameter=>value
 );

Parameters

 minversion     Minimum PostgreSQL version required, formatted like 8.2. If the
                database is an older version than this, the plugin will exit
                with an error.
 category       The category for this plugin. Copied directly to the config
                output. Default 'PostgreSQL'.
 title          The title for this plugin. Copied directly to the config output.
 info           The info for this plugin. Copied directly to the config output.
 vlabel         The vertical label for the graph. Copied directly to the config
                output.
 basename       For wildcard plugins, this is the base name of the plugin,
                including the trailing underscore.
 basequery      SQL query run to get the plugin values. The query should return
                two columns, one being the name of the counter and the second
                being the current value for the counter.
 pivotquery     Set to 1 to indicate that the query in basequery returns a single
                row, with one field for each counter. The name of the counter is
                taken from the returned column name, and the value from the
                first row in the result.
 configquery    SQL query run to generate the configuration information for the
                plugin. The query should return at least two columns, which are
                the name of the counter and the label of the counter. If
                a third column is present, it will be used as the info
                parameter.
 suggestquery   SQL query to run to generate the list of suggestions for a
                wildcard plugin. Don't forget to include ALL if the plugin
                supports aggregate statistics.
 autoconfquery  SQL query to run as the last step of "autoconf", to determine
                if the plugin should be run on this machine. Must return a single
                row, two columns columns. The first one is a boolean field
                representing yes or no, the second one a reason for "no".
 warning        The warning low and/or high thresholds.
 critical       The critical low and/or high thresholds.
 graphdraw      The draw parameter for the graph. The default is LINE1.
 graphtype      The type parameter for the graph. The default is GAUGE.
 graphperiod    The period for the graph. Copied directly to the config output.
 graphmin       The min parameter for the graph. The default is no minimum.
 graphmax       The max parameter for the graph. The default is no maximum.
 stack          If set to 1, all counters except the first one will be written
                with a draw type of STACK.
 base           Used for graph_args --base. Default is 1000, set to 1024 when
                returning sizes in Kb for example.
 wildcardfilter The SQL to substitute for when a wildcard plugin is run against
                a specific entity, for example a database. All occurrences of
                the string %%FILTER%% will be replaced with this string, and
                for each occurrence a parameter with the value of the filtering
                condition will be added to the DBI statement.
 paramdatabase  Makes the plugin connect to the database in the first parameter
                (wildcard plugins only) instead of 'template1'.
 defaultdb      Makes the plugin connect to the database specified in this
                parameter instead of 'template1'.
 extraconfig    This string is copied directly into the configuration output
                when the plugin is run in config mode, allowing low-level
                customization.
 postprocess    A function that's called with the result of the base query,
                and can post-process the result and return a new resultset.
 postconfig     A function that's called with the result of the config query,
                and can post-process the result and return a new resultset.
 postautoconf   A function that's called with the result of the autoconf query,
                and can post-process the result and return a new resultset.
 postsuggest    A function that's called with the result of the suggest query,
                and can post-process the result and return a new resultset.

Specifying queries

Queries specified in one of the parameters above can take one of two forms. The easiest one is a simple string, which will then always be executed, regardless of server version. The other form is an array, looking like this:
[
"SELECT 'default',... FROM ...",
[
"8.3", "SELECT 'query for 8.3 or earlier',... FROM ...",
"8.1", "SELECT 'query for 8.1 or earlier',... FROM ..."
]
] This array is parsed from top to bottom, so the entries must be in order of version number. The *last* value found where the version specified is higher than or equal to the version of the server will be used (yes, it counts backwards).

Processing

 $pg->Process();
 This command executes the plugin. It will automatically parse the ARGV array
 for commands given by Munin.