Dear all,
I'm using HBase 0.90.3.
In the Javadoc for HBaseAdmin, it's written: "Currently HBaseAdmin
instances are not expected to be long-lived. For example, an HBaseAdmin
instance will not ride over a Master restart."
As such, I re-create an HBaseAdmin object as soon as necessary (e.g. to
check that a table exists, get a table descriptor, alter tables, get the
ZK connection to synchronize my processes, ...) at different points on
my program (actually a library, which runs concurrently on different
programs on different JVMs possibly on a same node).
Moreover, I have to say that I cache HTable (and HTableDesciptor)
objects ; as such, those are long-lived.
A single Configuration object is used for all that stuff.
However, in the (unique) HBaseAdmin constructor, the code is the following:
public HBaseAdmin(Configuration c)
throws MasterNotRunningException, ZooKeeperConnectionException {
this.conf = HBaseConfiguration.create(c);
this.connection = HConnectionManager.getConnection(this.conf);
...
}
This makes the HConnectionManager create a new connection to Zookeeper
each time I create an HBaseAdmin.
Finally, I end up with numeous
2011-12-16 11:43:22,913 - WARN
[NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn$Factory@247] -
Too many connections from /10.59.14.112 - max is 60
in my zookeeper logs, which is not the case when I reuse a single
(long-lived) HBaseAdmin object.
To overcome this problem, I encapsulate any use of my admin objet with a
try/finally block to call a
HConnectionManager.deleteConnection(admin.getConfiguration(), true);
so that connections are closed...
I have to say I prefer using a long-lived HBaseAdmin and treat errors in
case of problem by recreating another one (which is far less frequent).
Is there any mean to force the HBaseAdmin reuse the Zookeeper client
connection ?
Best regards,
Frédéric
