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Posted to dev@hbase.apache.org by "Jean-Daniel Cryans (JIRA)" <ji...@apache.org> on 2009/08/27 19:32:59 UTC
[jira] Updated: (HBASE-1800) Too many ZK connections
[ https://issues.apache.org/jira/browse/HBASE-1800?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jean-Daniel Cryans updated HBASE-1800:
--------------------------------------
Attachment: HBASE-1800-v1.patch
This patch adds a singleton for ZKW. Has the advantage that whatever happens outside of ZK we will only have 1 connection per JVM. Without it openplaces' unit tests needed more than 100 client connections, now the default works just fine and there is less INFO log from ZK.
> Too many ZK connections
> -----------------------
>
> Key: HBASE-1800
> URL: https://issues.apache.org/jira/browse/HBASE-1800
> Project: Hadoop HBase
> Issue Type: Improvement
> Reporter: Jean-Daniel Cryans
> Fix For: 0.20.1, 0.21.0
>
> Attachments: HBASE-1800-v1.patch
>
>
> Currently we open tons of new connections to Zookeeper, like every time we instantiate a new HTable. There is a maximum number of client connections as described here:
> {code}
> <property>
> <name>hbase.zookeeper.property.maxClientCnxns</name>
> <value>30</value>
> <description>Property from ZooKeeper's config zoo.cfg.
> Limit on number of concurrent connections (at the socket level) that a
> single client, identified by IP address, may make to a single member of
> the ZooKeeper ensemble. Set high to avoid zk connection issues running
> standalone and pseudo-distributed.
> </description>
> </property>
> {code}
> If you hit that max number, ZK will just refuse your connections. Suppose you have 4 maps running on a server hosting a RS, you may actually lose your connection in the RS and eventually hit a session timeout. Maybe we should singleton ZKW?
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