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Posted to user@hbase.apache.org by Andrew Purtell <ap...@apache.org> on 2010/01/16 04:04:42 UTC
Re: HBase as DB tier for Tomcat - best practices to instantiate HTables?
A HTable object is not thread safe for writing. You'll need to watch
for that.
So use the pool of HTables as J-D suggests, or instantiate a group of
worker threads and allocate one HTable object for each at the top of
run() before entering the work loop.
- Andy
----- Original Message ----
> From: Jean-Daniel Cryans <jd...@apache.org>
> To: hbase-user@hadoop.apache.org
> Sent: Fri, January 15, 2010 5:40:14 PM
> Subject: Re: HBase as DB tier for Tomcat - best practices to instantiate HTables?
>
> You want to keep using a pool of HTables, see
> http://hadoop.apache.org/hbase/docs/r0.20.2/api/org/apache/hadoop/hbase/client/HTablePool.html
>
> J-D
>
> On Fri, Jan 15, 2010 at 5:35 PM, Jeyendran Balakrishnan
> wrote:
> > What's the best way to instantiate HTables when the HBase cluster is
> > being accessed from client code running inside a Tomcat web app? The web
> > app dooes the typical CRUD operations [but no table alteration].
> >
> > I read from the lists some time ago that instantiating a HTable in
> > servlet request is not advisable, since instantiating HTable is a bit
> > slow [accesses the meta regions?].
> >
> > So is the best practice for web apps to instantiate a HTable once at
> > startup and cache in the servlet context, and re-use it every request?
> >
> > In that case, is this thread safe [since each request spawns a different
> > thread]? On the other hand, syncing on the single HTable instance at the
> > web application level also slows down requests when contending for this
> > one instance.
> >
> > Also, is holding on to a single HTable instance in a long-running web
> > app a reliable approach?
> >
> > Or is it better to bite the bullet and instantiate an HTable per request
> > after all?
> >
> > Finally, has anybody looked into or have some kind of HTable pool [like
> > DB connection pools], which is a sort of medium between one HTable per
> > web app and one HTable per request?
> >
> > Any advice on best practices from the community would be greatly
> > appreciated.
> >
> > Thanks,
> > Jeyendran
> >
> >
RE: HBase as DB tier for Tomcat - best practices to instantiate HTables?
Posted by Jeyendran Balakrishnan <jb...@docomolabs-usa.com>.
Many thanks to Jean-Daniel, Andy and Vaibhav for the solutions.
In my case, I am not using Spring, so I am planning to use the
HTablePool approach.
-Jeyendran
-----Original Message-----
From: Vaibhav Puranik [mailto:vpuranik@gmail.com]
Sent: Saturday, January 16, 2010 3:05 PM
To: hbase-user@hadoop.apache.org
Subject: Re: HBase as DB tier for Tomcat - best practices to instantiate
HTables?
In case you are using Spring Framework, take a look at the following
issue:
http://jira.springframework.org/browse/SPR-5950
This shows how to configure HBase connection as a Spring bean.
Regards,
Vaibhav
On Fri, Jan 15, 2010 at 7:04 PM, Andrew Purtell <ap...@apache.org>
wrote:
> A HTable object is not thread safe for writing. You'll need to watch
> for that.
>
> So use the pool of HTables as J-D suggests, or instantiate a group of
> worker threads and allocate one HTable object for each at the top of
> run() before entering the work loop.
>
> - Andy
>
>
>
> ----- Original Message ----
> > From: Jean-Daniel Cryans <jd...@apache.org>
> > To: hbase-user@hadoop.apache.org
> > Sent: Fri, January 15, 2010 5:40:14 PM
> > Subject: Re: HBase as DB tier for Tomcat - best practices to
instantiate
> HTables?
> >
> > You want to keep using a pool of HTables, see
> >
>
http://hadoop.apache.org/hbase/docs/r0.20.2/api/org/apache/hadoop/hbase/
client/HTablePool.html
> >
> > J-D
> >
> > On Fri, Jan 15, 2010 at 5:35 PM, Jeyendran Balakrishnan
> > wrote:
> > > What's the best way to instantiate HTables when the HBase cluster
is
> > > being accessed from client code running inside a Tomcat web app?
The
> web
> > > app dooes the typical CRUD operations [but no table alteration].
> > >
> > > I read from the lists some time ago that instantiating a HTable in
> > > servlet request is not advisable, since instantiating HTable is a
bit
> > > slow [accesses the meta regions?].
> > >
> > > So is the best practice for web apps to instantiate a HTable once
at
> > > startup and cache in the servlet context, and re-use it every
request?
> > >
> > > In that case, is this thread safe [since each request spawns a
> different
> > > thread]? On the other hand, syncing on the single HTable instance
at
> the
> > > web application level also slows down requests when contending for
this
> > > one instance.
> > >
> > > Also, is holding on to a single HTable instance in a long-running
web
> > > app a reliable approach?
> > >
> > > Or is it better to bite the bullet and instantiate an HTable per
> request
> > > after all?
> > >
> > > Finally, has anybody looked into or have some kind of HTable pool
[like
> > > DB connection pools], which is a sort of medium between one HTable
per
> > > web app and one HTable per request?
> > >
> > > Any advice on best practices from the community would be greatly
> > > appreciated.
> > >
> > > Thanks,
> > > Jeyendran
> > >
> > >
>
>
>
>
>
>
Re: HBase as DB tier for Tomcat - best practices to instantiate
HTables?
Posted by Vaibhav Puranik <vp...@gmail.com>.
In case you are using Spring Framework, take a look at the following issue:
http://jira.springframework.org/browse/SPR-5950
This shows how to configure HBase connection as a Spring bean.
Regards,
Vaibhav
On Fri, Jan 15, 2010 at 7:04 PM, Andrew Purtell <ap...@apache.org> wrote:
> A HTable object is not thread safe for writing. You'll need to watch
> for that.
>
> So use the pool of HTables as J-D suggests, or instantiate a group of
> worker threads and allocate one HTable object for each at the top of
> run() before entering the work loop.
>
> - Andy
>
>
>
> ----- Original Message ----
> > From: Jean-Daniel Cryans <jd...@apache.org>
> > To: hbase-user@hadoop.apache.org
> > Sent: Fri, January 15, 2010 5:40:14 PM
> > Subject: Re: HBase as DB tier for Tomcat - best practices to instantiate
> HTables?
> >
> > You want to keep using a pool of HTables, see
> >
> http://hadoop.apache.org/hbase/docs/r0.20.2/api/org/apache/hadoop/hbase/client/HTablePool.html
> >
> > J-D
> >
> > On Fri, Jan 15, 2010 at 5:35 PM, Jeyendran Balakrishnan
> > wrote:
> > > What's the best way to instantiate HTables when the HBase cluster is
> > > being accessed from client code running inside a Tomcat web app? The
> web
> > > app dooes the typical CRUD operations [but no table alteration].
> > >
> > > I read from the lists some time ago that instantiating a HTable in
> > > servlet request is not advisable, since instantiating HTable is a bit
> > > slow [accesses the meta regions?].
> > >
> > > So is the best practice for web apps to instantiate a HTable once at
> > > startup and cache in the servlet context, and re-use it every request?
> > >
> > > In that case, is this thread safe [since each request spawns a
> different
> > > thread]? On the other hand, syncing on the single HTable instance at
> the
> > > web application level also slows down requests when contending for this
> > > one instance.
> > >
> > > Also, is holding on to a single HTable instance in a long-running web
> > > app a reliable approach?
> > >
> > > Or is it better to bite the bullet and instantiate an HTable per
> request
> > > after all?
> > >
> > > Finally, has anybody looked into or have some kind of HTable pool [like
> > > DB connection pools], which is a sort of medium between one HTable per
> > > web app and one HTable per request?
> > >
> > > Any advice on best practices from the community would be greatly
> > > appreciated.
> > >
> > > Thanks,
> > > Jeyendran
> > >
> > >
>
>
>
>
>
>