hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ted Yu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-3767) Cache the number of RS in HTable
Date Thu, 14 Apr 2011 04:24:05 GMT

    [ https://issues.apache.org/jira/browse/HBASE-3767?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13019684#comment-13019684
] 

Ted Yu commented on HBASE-3767:
-------------------------------

The javadoc fragment doesn't mention allowCoreThreadTimeOut.

>From http://fuseyism.com/classpath/doc/java/util/concurrent/ThreadPoolExecutor-source.html:
{code:Java}
 494:     Runnable getTask() {
 495:         for (;;) {
 496:             try {
 497:                 switch (runState) {
 498:                 case RUNNING: {
 499:                     // untimed wait if core and not allowing core timeout
 500:                     if (poolSize <= corePoolSize && !allowCoreThreadTimeOut)
 501:                         return workQueue.take();
 502: 
 503:                     long timeout = keepAliveTime;
 504:                     if (timeout <= 0) // die immediately for 0 timeout
 505:                         return null;
 506:                     Runnable r = workQueue.poll(timeout, TimeUnit.NANOSECONDS);
 507:                     if (r != null)
 508:                         return r;
 509:                     if (poolSize > corePoolSize || allowCoreThreadTimeOut)
 510:                         return null; // timed out
 511:                     // Else, after timeout, the pool shrank. Retry
 512:                     break;
 513:                 }
{code:Java}
In HTable(), allowCoreThreadTimeOut is set to true. So we're not bounded by corePoolSize threads.

> Cache the number of RS in HTable
> --------------------------------
>
>                 Key: HBASE-3767
>                 URL: https://issues.apache.org/jira/browse/HBASE-3767
>             Project: HBase
>          Issue Type: Improvement
>    Affects Versions: 0.90.2
>            Reporter: Jean-Daniel Cryans
>             Fix For: 0.90.3
>
>         Attachments: HBASE-3767.patch
>
>
> When creating a new HTable we have to query ZK to learn about the number of region servers
in the cluster. That is done for every single one of them, I think instead we should do it
once per JVM and then reuse that number for all the others.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message