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EXPLAIN

Synopsis

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EXPLAIN (sql_expression|query_id);

Description

Show the execution plan for a SQL expression or, given the ID of a running query, show the execution plan plus additional runtime information and metrics. Statements such as DESCRIBE EXTENDED, for example, show the IDs of queries related to a stream or table.

For more information, see ksqlDB Query Lifecycle.

Example

The following statement shows the execution plan for a push query named ctas_ip_sum on a topic named CLICKSTREAM.

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EXPLAIN ctas_ip_sum;

Your output should resemble:

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Type                 : QUERY
SQL                  : CREATE TABLE IP_SUM as SELECT ip,  sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES;


Local runtime statistics
------------------------
messages-per-sec:     104.38   total-messages:       14238     last-message: 12/14/17 4:30:42 PM GMT
    failed-messages:          0      last-failed:         n/a
(Statistics of the local Ksql Server interaction with the Kafka topic IP_SUM)

Execution plan
--------------
    > [ PROJECT ] Schema: [IP : STRING , KBYTES : INT64].
            > [ AGGREGATE ] Schema: [CLICKSTREAM.IP : STRING , CLICKSTREAM.BYTES : INT64 , KSQL_AGG_VARIABLE_0 : INT64].
                    > [ PROJECT ] Schema: [CLICKSTREAM.IP : STRING , CLICKSTREAM.BYTES : INT64].
                            > [ REKEY ] Schema: [CLICKSTREAM.ROWTIME : INT64 , CLICKSTREAM.IP : STRING , CLICKSTREAM._TIME : INT64 , CLICKSTREAM.TIME : STRING , CLICKSTREAM.REQUEST : STRING , CLICKSTREAM.STATUS : INT32 , CLICKSTREAM.USERID : INT32 , CLICKSTREAM.BYTES : INT64 , CLICKSTREAM.AGENT : STRING].
                                    > [ SOURCE ] Schema: [CLICKSTREAM.ROWTIME : INT64 , CLICKSTREAM._TIME : INT64 , CLICKSTREAM.TIME : STRING , CLICKSTREAM.IP : STRING , CLICKSTREAM.REQUEST : STRING , CLICKSTREAM.STATUS : INT32 , CLICKSTREAM.USERID : INT32 , CLICKSTREAM.BYTES : INT64 , CLICKSTREAM.AGENT : STRING].


Processing topology
-------------------
Sub-topologies:
    Sub-topology: 0
    Source: KSTREAM-SOURCE-0000000000 (topics: [clickstream])
        --> KSTREAM-MAP-0000000001
    Processor: KSTREAM-MAP-0000000001 (stores: [])
        --> KSTREAM-TRANSFORMVALUES-0000000002
        <-- KSTREAM-SOURCE-0000000000
Last update: 2020-10-19