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Posted to issues@activemq.apache.org by "Ephemeris Lappis (Jira)" <ji...@apache.org> on 2020/10/27 13:20:00 UTC
[jira] [Commented] (AMQ-6770) Slow events processing
[ https://issues.apache.org/jira/browse/AMQ-6770?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17221422#comment-17221422 ]
Ephemeris Lappis commented on AMQ-6770:
---------------------------------------
Hello.
I get exactly the same issue using PostgreSQL too when a lot of messages are pending in a queue, with a relatively big size (from 32 MB to 96 MB). I've also traced SQL queries. After the consumer is started (a Camel route in my case) AMQ executes a repeated statement to read all the messages, reducing each time the interval (parameter $3) : SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID. This leads to OOM errors (usually at the JDBC driver level), even with a big JVM heap because of the cumulative size of all the pending messages rows.
I understand that a fix is considered for both Oracle and PostgreSQL. As my ActiveMQ is rather old (5.14), I'd like to know if any workaround can be applied to resolve our issue, using some parameter (on adapter, broker, consumer, etc.) that may alter the adapter behavior such a way that the memory allocation keeps under control ?
Thanks in advance.
Regards.
> Slow events processing
> ----------------------
>
> Key: AMQ-6770
> URL: https://issues.apache.org/jira/browse/AMQ-6770
> Project: ActiveMQ
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 5.14.5
> Reporter: Jakub
> Assignee: Jean-Baptiste Onofré
> Priority: Critical
> Attachments: activemq-jdbc-store-limit.patch, consumer-output.txt
>
>
> When ActiveMQ is configured with JDBC persistence storage (postgres) and there is many pending events (more than 5 000 000) consumers receive events in a bulk only every several seconds even if a queue contains a lot of events.
> To get such state of AMQ I've used activemq-perf-maven-plugin with below settings:
> {code}
> mvn org.apache.activemq.tooling:activemq-perf-maven-plugin:consumer -Dconsumer.destName=queue://TEST.FOO -Dconsumer.recvDuration=300000 -Dconsumer.sessAckMode=tran
> sacted -DsysTest.reportType=verbose -DsysTest.numClients=3 -Dfactory.asyncSession=false -Dfactory.prefetchQueue=1 -Dconsumer.sessTransacted=true -Dfactory.prefetchPolicy.queuePrefetch=1
> {code}
> Output and result of execution attached.
> On database side there are information that execution of query is slow:
> {code}
> 2017-07-13 04:37:38 UTC;activemq;11184;5966f908.2bb0;7/2253014;0;1;LOG: duration: 7706.308 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:37:38 UTC;activemq;11184;5966f908.2bb0;7/2253014;0;2;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5583825'
> 2017-07-13 04:37:47 UTC;activemq;11184;5966f908.2bb0;7/2255501;0;3;LOG: duration: 7921.731 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:37:47 UTC;activemq;11184;5966f908.2bb0;7/2255501;0;4;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5586325'
> 2017-07-13 04:37:56 UTC;activemq;6556;5966f907.199c;6/1900865;0;1;LOG: duration: 8110.328 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:37:56 UTC;activemq;6556;5966f907.199c;6/1900865;0;2;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5588825'
> 2017-07-13 04:38:03 UTC;activemq;6556;5966f907.199c;6/1901366;0;3;LOG: duration: 7711.928 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:03 UTC;activemq;6556;5966f907.199c;6/1901366;0;4;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5589325'
> 2017-07-13 04:38:11 UTC;activemq;2148;5966f359.864;2/2670600;0;3;LOG: duration: 7737.924 ms execute S_5: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:11 UTC;activemq;2148;5966f359.864;2/2670600;0;4;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5589825'
> 2017-07-13 04:38:20 UTC;activemq;2148;5966f359.864;2/2671104;0;5;LOG: duration: 7750.932 ms execute S_5: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:20 UTC;activemq;2148;5966f359.864;2/2671104;0;6;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5590325'
> 2017-07-13 04:38:28 UTC;activemq;6556;5966f907.199c;6/1902887;0;5;LOG: duration: 7718.725 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:28 UTC;activemq;6556;5966f907.199c;6/1902887;0;6;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5590825'
> 2017-07-13 04:38:35 UTC;activemq;11184;5966f908.2bb0;7/2259004;0;5;LOG: duration: 7685.510 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:35 UTC;activemq;11184;5966f908.2bb0;7/2259004;0;6;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5591325'
> 2017-07-13 04:38:43 UTC;activemq;2148;5966f359.864;2/2672124;0;7;LOG: duration: 7717.112 ms execute S_5: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:43 UTC;activemq;2148;5966f359.864;2/2672124;0;8;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5591825'
> 2017-07-13 04:38:51 UTC;activemq;11184;5966f908.2bb0;7/2259996;0;7;LOG: duration: 7717.112 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:51 UTC;activemq;11184;5966f908.2bb0;7/2259996;0;8;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5592325'
> 2017-07-13 04:38:59 UTC;activemq;11184;5966f908.2bb0;7/2260488;0;9;LOG: duration: 7682.116 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:38:59 UTC;activemq;11184;5966f908.2bb0;7/2260488;0;10;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5592825'
> 2017-07-13 04:39:07 UTC;activemq;11184;5966f908.2bb0;7/2260989;0;11;LOG: duration: 7718.309 ms execute S_3: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:39:07 UTC;activemq;11184;5966f908.2bb0;7/2260989;0;12;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5593325'
> 2017-07-13 04:39:15 UTC;activemq;7472;5966e588.1d30;5/1987914;0;3;LOG: duration: 7779.711 ms execute S_5: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:39:15 UTC;activemq;7472;5966e588.1d30;5/1987914;0;4;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5594325'
> 2017-07-13 04:39:23 UTC;activemq;7472;5966e588.1d30;5/1988403;0;5;LOG: duration: 7789.711 ms execute S_5: SELECT ID, MSG FROM ACTIVEMQ_MSGS WHERE CONTAINER=$1 AND ID < $2 AND ID > $3 AND XID IS NULL ORDER BY ID
> 2017-07-13 04:39:23 UTC;activemq;7472;5966e588.1d30;5/1988403;0;6;DETAIL: parameters: $1 = 'queue://TEST.FOO', $2 = '11786094', $3 = '5594825'
> {code}
> I've tried to improve performance on database side by creating new indexes but it hasn't helped. The problem is in number of rows that the query returns (in may case more than 5 000 000).
> After analyzing AMQ code a fix for it seams easy. Only first _maxPageSize_ rows (in my case 500) are used so rest of rows can be skipped and even not processed by database.
> I think that the _findNextMessagesStatement_ should be changed to:
> {code}
> findNextMessagesStatement = "SELECT ID, MSG FROM " + getFullMessageTableName()
> + " WHERE CONTAINER=? AND ID < ? AND ID > ? AND XID IS NULL ORDER BY ID LIMIT ?";
> {code}
> where the LIMIT is set to _maxPageSize_.
> What do you think about such change? Is it safe in context of data consistency and events processing in ActiveMQ? I know that LIMIT may not be a solution for everybody
> as it isn't supported by [all databases|https://stackoverflow.com/questions/1528604/how-universal-is-the-limit-statement-in-sql].
> There is _org.apache.activemq.store.jdbc.JDBCAdapter.limitQuery_ method that should modify query to limit amount of rows but it has valuable implementation only in _OracleJDBCAdapter_, for other databases the method doesn't modify a query so limit isn't added.
> I also wonder why the range in query ID < $2 AND ID > $3 is so wide?
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