Repository: incubator-impala Updated Branches: refs/heads/master 927034682 -> d6b5f82e3
IMPALA-5108: [DOCS] Explain 50% margin for idle_* settings Add a note that idle_session_timeout and idle_query_timeout might take up to 50% longer than the specified interval before cancellation occurs. Also rearrange the text a little to put QUERY_TIMEOUT_S explanation adjacent to the idle_query_timeout explanation. This results in an indentation change that makes the diff look bigger than it really is. The <note> element is the only actual added content. Change-Id: I0b19912dac1df13bfcbcb67f0bd4ed0064ad8db9 Reviewed-on: http://gerrit.cloudera.org:8080/6463 Tested-by: Impala Public Jenkins Reviewed-by: Michael Brown <[email protected]> Project: http://git-wip-us.apache.org/repos/asf/incubator-impala/repo Commit: http://git-wip-us.apache.org/repos/asf/incubator-impala/commit/9efed591 Tree: http://git-wip-us.apache.org/repos/asf/incubator-impala/tree/9efed591 Diff: http://git-wip-us.apache.org/repos/asf/incubator-impala/diff/9efed591 Branch: refs/heads/master Commit: 9efed59163fd7c970614cb31d72e89cf0954a32f Parents: 9270346 Author: John Russell <[email protected]> Authored: Thu Mar 23 10:36:45 2017 -0700 Committer: Michael Brown <[email protected]> Committed: Tue May 9 22:08:16 2017 +0000 ---------------------------------------------------------------------- docs/topics/impala_timeouts.xml | 52 +++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 19 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/9efed591/docs/topics/impala_timeouts.xml ---------------------------------------------------------------------- diff --git a/docs/topics/impala_timeouts.xml b/docs/topics/impala_timeouts.xml index 5b843d4..80e5c9b 100644 --- a/docs/topics/impala_timeouts.xml +++ b/docs/topics/impala_timeouts.xml @@ -101,22 +101,34 @@ Trying to re-register with state-store</codeblock> <ul> <li> - The <codeph>--idle_query_timeout</codeph> option specifies the time in seconds after - which an idle query is cancelled. This could be a query whose results were all fetched - but was never closed, or one whose results were partially fetched and then the client - program stopped requesting further results. This condition is most likely to occur in - a client program using the JDBC or ODBC interfaces, rather than in the interactive - <cmdname>impala-shell</cmdname> interpreter. Once the query is cancelled, the client - program cannot retrieve any further results. + <p> + The <codeph>--idle_query_timeout</codeph> option specifies the time in seconds after + which an idle query is cancelled. This could be a query whose results were all fetched + but was never closed, or one whose results were partially fetched and then the client + program stopped requesting further results. This condition is most likely to occur in + a client program using the JDBC or ODBC interfaces, rather than in the interactive + <cmdname>impala-shell</cmdname> interpreter. Once the query is cancelled, the client + program cannot retrieve any further results. + </p> + + <p rev="2.0.0"> + You can reduce the idle query timeout by using the <codeph>QUERY_TIMEOUT_S</codeph> + query option. Any non-zero value specified for the <codeph>--idle_query_timeout</codeph> startup + option serves as an upper limit for the <codeph>QUERY_TIMEOUT_S</codeph> query option. + A zero value for <codeph>--idle_query_timeout</codeph> disables query timeouts. + See <xref href="impala_query_timeout_s.xml#query_timeout_s"/> for details. + </p> </li> <li> - The <codeph>--idle_session_timeout</codeph> option specifies the time in seconds after - which an idle session is expired. A session is idle when no activity is occurring for - any of the queries in that session, and the session has not started any new queries. - Once a session is expired, you cannot issue any new query requests to it. The session - remains open, but the only operation you can perform is to close it. The default value - of 0 means that sessions never expire. + <p> + The <codeph>--idle_session_timeout</codeph> option specifies the time in seconds after + which an idle session is expired. A session is idle when no activity is occurring for + any of the queries in that session, and the session has not started any new queries. + Once a session is expired, you cannot issue any new query requests to it. The session + remains open, but the only operation you can perform is to close it. The default value + of 0 means that sessions never expire. + </p> </li> </ul> @@ -125,12 +137,14 @@ Trying to re-register with state-store</codeblock> <xref href="impala_config_options.xml#config_options"/>. </p> - <p rev="2.0.0"> - You can reduce the idle query timeout by using the <codeph>QUERY_TIMEOUT_S</codeph> - query option. Any value specified for the <codeph>--idle_query_timeout</codeph> startup - option serves as an upper limit for the <codeph>QUERY_TIMEOUT_S</codeph> query option. - See <xref href="impala_query_timeout_s.xml#query_timeout_s"/> for details. - </p> + <note> + <p rev="IMPALA-5108"> + Impala checks periodically for idle sessions and queries + to cancel. The actual idle time before cancellation might be up to 50% greater than + the specified configuration setting. For example, if the timeout setting was 60, the + session or query might be cancelled after being idle between 60 and 90 seconds. + </p> + </note> </conbody>
