The metrics collector extension in Greenplum Database defines custom server configuration parameters to configure metrics collection options. If the metrics collector extension is installed and the value of the
shared_preload_libraries configuration parameter includes
metrics_collector when Greenplum Database starts, these parameters can be viewed and set using the Greenplum Database
Enables collection of query metrics in Greenplum Database. When
on, the metrics collector sends query metrics to the Greenplum Command Center agent.
off the metrics collector does not collect queries executed by the gpmon user in the gpperfmon database or plan node history for queries that run in less than ten seconds (or
min_query_time, if it is set and greater than 10 seconds). If enabled in a session, the metrics collector collects those queries in the session.
The port number to send query metrics. The metrics collector sends query metrics to the Greenplum Command Center agent process on this port.
This parameter is enabled by default and must remain enabled. It allows the use of external tables that execute OS commands or scripts on the segment hosts. The Command Center agents use this type of external tables to collect current system metrics from the segments.
When on, enables query metrics collection. The default is off. After setting this configuration parameter, Greenplum Database must be restarted for the change to take effect.
When on, Command Center saves to the
gpmetrics.gpcc_queries_history table the full query text for queries whose text is longer than 100 KB. When off, Command Center saves only 5KB of query text for queries whose text is longer than 100 KB. It is turned off by default.
NOTE: The full query text is always saved for queries whose text is shorter than 100 KB, regardless of what
gpcc.enable_save_full_query_text is set to.
gpcc.enable_send_lock_info Turn this parameter off to reduce Command Center's memory consumption by stopping Command Center from collecting lock information for queries. When it is off, the Query Monitor will not report a query's lock information or whether the query is blocked by another query. NOTE: This GUC was introduced in maintenance release 6.7.1.
You must have superuser permission to change this parameter. In addition, you must restart Greenplum Database in order for the change to take effect.
It is turned on by default.
When off, Command Center will not display some query details -- such as the visual query plan tree -- and some statistics. This will reduce Command Center's memory consumption. It is turned on by default.
gpcc.enable_send_inner_query When turned on, users can see the statements within functions that the query is calling when they click the Inner Queries tab in the query monitor's Query Detail view. It is turned off by default.
gp_instrument_shmem_size The amount of shared memory, in kilobytes, allocated for query metrics. The default is 5120 and the maximum is 131072. At startup, if
gp_enable_query_metrics is set to on, Greenplum Database allocates space in shared memory to save query metrics. This memory is organized as a header and a list of slots. The number of slots needed depends on the number of concurrent queries and the number of execution plan nodes per query. The default value, 5120, is based on a Greenplum Database system that executes a maximum of about 250 concurrent queries with 120 nodes per query. If the
gp_enable_query_metrics configuration parameter is off, or if the slots are exhausted, the metrics are maintained in local memory instead of in shared memory.
shared_preload_libraries A comma-separated list of shared libraries that are to be preloaded when Greenplum Database starts. The workload management and query metrics extension libraries must be included in this configuration parameter to use Greenplum Command Center.
track_activities Enables the collection of information on the currently executing command of each session, along with the time when that command began execution. The default value is true. Only superusers can change this setting.