STL_MERGEJOIN

Analyzes merge join execution steps for queries.

This view 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.

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 executed.
starttime	timestamp	Time in UTC that the query started executing, 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 executing, 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 execute the step.
rows	bigint	Total number of rows that were processed.
tbl	integer	Table ID. This is the ID for the inner table that was used in the merge join.
checksum	bigint	This information is for internal use only.

Sample queries

The following example returns merge join results for the most recent query.

select sum(s.qtysold), e.eventname
from event e, listing l, sales s
where e.eventid=l.eventid
and l.listid= s.listid
group by e.eventname;

select * from stl_mergejoin where query=pg_last_query_id();

 userid | query | slice | segment | step |         starttime   |          endtime    | tasknum | rows | tbl
--------+-------+-------+---------+------+---------------------+---------------------+---------+------+-----
    100 | 27399 |     3 |       4 |    4 | 2013-10-02 16:30:41 | 2013-10-02 16:30:41 |      19 |43428 | 240
    100 | 27399 |     0 |       4 |    4 | 2013-10-02 16:30:41 | 2013-10-02 16:30:41 |      19 |43159 | 240
    100 | 27399 |     2 |       4 |    4 | 2013-10-02 16:30:41 | 2013-10-02 16:30:41 |      19 |42778 | 240
    100 | 27399 |     1 |       4 |    4 | 2013-10-02 16:30:41 | 2013-10-02 16:30:41 |      19 |43091 | 240