The tcp_stats_* tables store statistical metrics about TCP communications for a Greenplum Database instance.
These tables are in place for future use and are not currently populated.
There are three system tables, all having the same columns:
- tcp_stats_now is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data.
- tcp_stats_tail is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. This is a transitional table for TCP statistical data that has been cleared from tcp_stats_now but has not yet been committed to tcp_stats_history. It typically only contains a few minutes worth of data.
- tcp_stats_history is a regular table that stores historical TCP statistical data. It is pre-partitioned into monthly partitions. Partitions are automatically added in two month increments as needed. Administrators must drop old partitions for the months that are no longer needed.
|segments_received||bigint||Number of TCP segments received.|
|segments_sent||bigint||Number of TCP segments sent.|
|segments_retransmitted||bigint||Number of TCP segments retransmitted.|
|active_connections||int||Number of active TCP connections.|
|passive_connections||int||Number of passive TCP connections.|
|failed_connection_attempts||int||Number of failed TCP connection attempts.|
|connections_established||int||Number of TCP connections established.|
|connection_resets_received||int||Number of TCP connection resets received.|
|connection_resets_sent||int||Number of TCP connection resets sent.|