SVCS_PLAN_INFO - Amazon Redshift
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SVCS_PLAN_INFO

Use the SVCS_PLAN_INFO table to look at the EXPLAIN output for a query in terms of a set of rows. This is an alternative way to look at query plans.

Note

System views with the prefix SVCS provide details about queries on both the main and concurrency scaling clusters. The views are similar to the tables with the prefix STL except that the STL tables provide information only for queries run on the main cluster.

SVCS_PLAN_INFO 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.
nodeid integer Plan node identifier, where a node maps to one or more steps in the execution of the query.
segment integer Number that identifies the query segment.
step integer Number that identifies the query step.
locus integer Location where the step runs. 0 if on a compute node and 1 if on the leader node.
plannode integer Enumerated value of the plan node. See the following table for enums for plannode. (The PLANNODE column in SVCS_EXPLAIN contains the plan node text.)
startupcost double precision The estimated relative cost of returning the first row for this step.
totalcost double precision The estimated relative cost of executing the step.
rows bigint The estimated number of rows that will be produced by the step.
bytes bigint The estimated number of bytes that will be produced by the step.

Sample queries

The following examples compare the query plans for a simple SELECT query returned by using the EXPLAIN command and by querying the SVCS_PLAN_INFO table.

explain select * from category; QUERY PLAN ------------------------------------------------------------- XN Seq Scan on category (cost=0.00..0.11 rows=11 width=49) (1 row) select * from category; catid | catgroup | catname | catdesc -------+----------+-----------+-------------------------------------------- 1 | Sports | MLB | Major League Baseball 3 | Sports | NFL | National Football League 5 | Sports | MLS | Major League Soccer ... select * from svcs_plan_info where query=256; query | nodeid | segment | step | locus | plannode | startupcost | totalcost | rows | bytes -------+--------+---------+------+-------+----------+-------------+-----------+------+------- 256 | 1 | 0 | 1 | 0 | 104 | 0 | 0.11 | 11 | 539 256 | 1 | 0 | 0 | 0 | 104 | 0 | 0.11 | 11 | 539 (2 rows)

In this example, PLANNODE 104 refers to the sequential scan of the CATEGORY table.

select distinct eventname from event order by 1; eventname ------------------------------------------------------------------------ .38 Special 3 Doors Down 70s Soul Jam A Bronx Tale ... explain select distinct eventname from event order by 1; QUERY PLAN ------------------------------------------------------------------------------------- XN Merge (cost=1000000000136.38..1000000000137.82 rows=576 width=17) Merge Key: eventname -> XN Network (cost=1000000000136.38..1000000000137.82 rows=576 width=17) Send to leader -> XN Sort (cost=1000000000136.38..1000000000137.82 rows=576 width=17) Sort Key: eventname -> XN Unique (cost=0.00..109.98 rows=576 width=17) -> XN Seq Scan on event (cost=0.00..87.98 rows=8798 width=17) (8 rows) select * from svcs_plan_info where query=240 order by nodeid desc; query | nodeid | segment | step | locus | plannode | startupcost | totalcost | rows | bytes -------+--------+---------+------+-------+----------+------------------+------------------+------+-------- 240 | 5 | 0 | 0 | 0 | 104 | 0 | 87.98 | 8798 | 149566 240 | 5 | 0 | 1 | 0 | 104 | 0 | 87.98 | 8798 | 149566 240 | 4 | 0 | 2 | 0 | 117 | 0 | 109.975 | 576 | 9792 240 | 4 | 0 | 3 | 0 | 117 | 0 | 109.975 | 576 | 9792 240 | 4 | 1 | 0 | 0 | 117 | 0 | 109.975 | 576 | 9792 240 | 4 | 1 | 1 | 0 | 117 | 0 | 109.975 | 576 | 9792 240 | 3 | 1 | 2 | 0 | 114 | 1000000000136.38 | 1000000000137.82 | 576 | 9792 240 | 3 | 2 | 0 | 0 | 114 | 1000000000136.38 | 1000000000137.82 | 576 | 9792 240 | 2 | 2 | 1 | 0 | 123 | 1000000000136.38 | 1000000000137.82 | 576 | 9792 240 | 1 | 3 | 0 | 0 | 122 | 1000000000136.38 | 1000000000137.82 | 576 | 9792 (10 rows)