STL_RETURN - Amazon Redshift

STL_RETURN

Contains details for return steps in queries. A return step returns the results of queries completed on the compute nodes to the leader node. The leader node then merges the data and returns the results to the requesting client. For queries completed on the leader node, a return step returns results to the client.

A query consists of multiple segments, and each segment consists of one or more steps. For more information, see Query processing.

STL_RETURN is visible to all users. Superusers can see all rows; regular users can see only their own data. For more information, see Visibility of data in system tables and views.

Note

STL_RETURN only contains queries run on main clusters. It doesn't contain queries run on concurrency scaling clusters. To access queries run on both main and concurrency scaling clusters, we recommend that you use the SYS monitoring view SYS_QUERY_DETAIL . The data in the SYS monitoring view is formatted to be easier to use and understand.

Table columns

Column name Data type Description
userid integer ID of the user who generated the entry.
query integer Query ID. The query column can be used to join other system tables and views.
slice integer Number that identifies the slice where the query was running.
segment integer Number that identifies the query segment.
step integer Query step that ran.
starttime timestamp Time in UTC that the query started. Total time includes queuing and execution. with 6 digits of precision for fractional seconds. For example: 2009-06-12 11:29:19.131358.
endtime timestamp Time in UTC that the query finished. Total time includes queuing and execution. with 6 digits of precision for fractional seconds. For example: 2009-06-12 11:29:19.131358.
tasknum integer Number of the query task process that was assigned to run the step.
rows bigint Total number of rows that were processed.
bytes bigint Size, in bytes, of all the output rows for the step.
packets integer Total number of packets sent over the network.
checksum bigint This information is for internal use only.

Sample queries

The following query shows which steps in the most recent query were performed on each slice.

SELECT query, slice, segment, step, endtime, rows, packets from stl_return where query = pg_last_query_id(); query | slice | segment | step | endtime | rows | packets -------+--------+---------+------+----------------------------+------+--------- 4 | 2 | 3 | 2 | 2013-12-27 01:43:21.469043 | 3 | 0 4 | 3 | 3 | 2 | 2013-12-27 01:43:21.473321 | 0 | 0 4 | 0 | 3 | 2 | 2013-12-27 01:43:21.469118 | 2 | 0 4 | 1 | 3 | 2 | 2013-12-27 01:43:21.474196 | 0 | 0 4 | 4 | 3 | 2 | 2013-12-27 01:43:21.47704 | 2 | 0 4 | 5 | 3 | 2 | 2013-12-27 01:43:21.478593 | 0 | 0 4 | 12811| 4 | 1 | 2013-12-27 01:43:21.480755 | 0 | 0 (7 rows)