Queries are not killed even if the client sends a cancel request

[fox123]

Hi all,

I am experiencing a problem when I try to cancel a query that is processed locally in Teiid. For example, if I run a query like this:

WITH x as (
  SELECT * FROM SYS.COLUMNS LIMIT 70
), y as (
  SELECT * FROM SYS.COLUMNS LIMIT 6
)
SELECT COUNT(*)
FROM
  x as x1,
  x as x2,
  x as x3,
  x as x4,
  y as y1

it is normally executed in around 20 seconds.

If I try to cancel this query from a JDBC client, the cancel request is correctly sent to the server and in fact I can see this message in the log:

19:37:57,544 INFO  [org.teiid.COMMAND_LOG] (New I/O worker #2) szgJ/5Ahjzdd     CANCEL USER COMMAND:    endTime=2015-10-20 19:37:57.544 requestID=szgJ/5Ahjzdd.16     txID=null       sessionID=szgJ/5Ahjzdd  principal=user@teiid-security   vdbName=test    vdbVersion=1    finalRowCount=null

but the query actually continues to run for 20 seconds and it is not killed.

The behavior is the same if the query is not based on SYS tables.

On the other side, it seems that the query is correctly and immediately cancelled if the query is completely pushed down to an underlying datasource.

Is it a normal behavior (maybe depending on the client) or is it an issue with the server?

[shawkins]

> Is it a normal behavior (maybe depending on the client) or is it an issue with the server?

The cancellation behavior is based upon cancelling source queries and stopping query execution at well known spot in batch processing.  Internal table queries are currently not registered the same way as source queries to external systems, thus there may not be an immediate cancellation depending upon the type of plan that is being executed.  That is certainly something you can log an issue for if you have a case where you need more immediate cancellation.

[fox123]

Thanks for the very quick reply.

I executed some additional tests and logged an issue here: [TEIID-3781] Queries are not killed even if the client sends a cancel request - JBoss Issue Tracker