Hi there,
For which versions of HBase is asyncbase working ? Can't find that on
the website.
Does it supports external schema changes (new/deleted table/column
family by an external thread/process)?
What about HTablePool regarding this last question ?
Is is really enough to use an HTablePool like this in multithreaded
environment ?
e.g. (unchecked code follows)
thread1 and thread2:
while (! shouldStop) {
HTableInterface t = pool.get("sometable");
try {
//no need for synchronized(t) here as both threads receive
different instances at same time, right ?
//works with t
} finally {
t.close();
}
}
What to do when application is ended ? Is it mandatory to call
closeTablePool ?
It would be great if HTableInterface could extend java.io.Closeable so
that one could write
try(t) {
//work with t
}
Sorry if questions look simple, but I'm not sure just from the Javadoc.
Cheers !
Le 26/08/2011 09:08, Ben Cuthbert a écrit :
Hi Andy
We are using the stubleupon async client. Very fast and good.
On 26 Aug 2011, at 04:58, Zhong, Andy wrote:
Hey Michael,
I am also looking to the performance gain to use HTablePool instead of
created HTable using a singleton instance of HBaseConfiguration. If the
use case is for a web service to handle multi-threaded write/reading
from a single Hbase table, are you suggest to use HTablePool to
pre-created a pool of Htable instances?
But below two comments concern me:
1. Concern of restarting Hadoop/HBase cluster:
http://comments.gmane.org/gmane.comp.java.hadoop.hbase.user/13128
"The problem with the HTablePool is that it does not "ride over restart"
meaning that if you need to restart your cluster, HtablePool will still
be pointing at the old ports and not realize the cluster is back-up."
2. Seems no performance gain, and even worse:
http://www.srikanthps.com/2011/06/hbase-benchmarking-for-multi-threaded.
html if no of concurrent put<10000.
3. Does anyone uses glisthub: claim a fully asynchronous, non-blocking,
thread-safe, high-performance HBase client (not sure if anyone uses it):
http://github.com/stumbleupon/asynchbase
What do you think of it, and welcome any one's advices or comments on
this.
Thanks,
Andy Zhong
-----Original Message-----
From: Michael Segel [mailto:[email protected]]
Sent: Tuesday, August 23, 2011 10:57 PM
To: [email protected]
Subject: RE: question on HTablePool and threads
Sujee,
You are correct in creating a separate HTable instance in each thread.
(HTable isn't thread safe, but since the scope is within the thread it
works.)
You could use the HTablePool class, but I don't think its a better
solution for what you are doing.
In your example it sounds like you're creating the connection in each
thread and you're using it for the life of the thread/application. So
there's no real benefit in trying to create a pool of threads and then
request a thread from the pool.
JMHO
-Mike
From: [email protected]
Date: Tue, 23 Aug 2011 16:34:32 -0700
Subject: question on HTablePool and threads
To: [email protected]
Hi all,
Right now I have a java client program that accesses Hbase in
multiple threads for read / write. Each thread creates its own
instance of HTable of the _same_ table.
I am looking into HTablePool class. Not clear on if it is a
correct/better choice for accessing the _same_ table with multiple
threads.
Is this a valid / thread-safe ?
create HtablePool in 'main'
pass HTablePool instance to threads
each thread does a 'htablepool.get(table)'
read / write to table
'htablepool.put (table) ' when done (all this is done within a
single JVM)
thanks
Sujee Maniyam
http://sujee.net
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