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The udp_* tables store statistical metrics about UDP communications for a Greenplum Database instance.
There are three system tables, all having the same columns:
- udp_now is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data.
- udp_tail is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. This is a transitional table for UDP statistical data that has been cleared from udp_now but has not yet been committed to udp_history. It typically only contains a few minutes worth of data.
- udp_history is a regular table that stores historical UDP statistical metrics. 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.
|ctime||timestamp(0) with no time zone||Time this record was created.|
|hostname||varchar(64)||The hostname associated with this measurement.|
|packets_received||bigint||Number of UDP packets received.|
|packets_sent||bigint||Number of UDP packets sent.|
|packets_received_unknown_port||int||Number of UDP packets received on unknown ports.|
|packet_receive_errors||bigint||Number of errors encountered during UDP packet receive.|