From: Craig Ringer <ringerc@ringerc.id.au>
To: David Fetter <david@fetter.org>
Cc: Sylvain Mougenot <smougenot@sqli.com>
Cc: pgsql-jdbc@postgresql.org
Subject: Re: [SQL] JDBC Statement.setQueryTimeout : is there plan to implement this?
Date: Thu, 15 Dec 2011 12:45:57 +0800
Message-ID: <4EE97B85.50909@ringerc.id.au> (raw)
In-Reply-To: <4EE968FF.5010604@ringerc.id.au>
References: <CACKdPFjK_UsZ5wExD-RvBbvi6Zo-VYtoxQsCUpWXzTN9kywj7w@mail.gmail.com>
<4EE8AC41.2040505@ringerc.id.au>
<20111214161349.GA31176@fetter.org>
<4EE968FF.5010604@ringerc.id.au>
> I've popped a question up here:
>
>
> http://stackoverflow.com/questions/8514725/obtaining-a-java-util-timer-or-equivalent-in-a-javaee-fri...
>
> to see if I can get some broader input on the issue of portable timers.
... and boy am I glad I did, thanks to Bauke Scholtz (BalusC) on SO.
It looks like we can probably use a ScheduledThreadPoolExecutor safely
from within a Java EE container or servlet container, so long as:
- We never let EE application code that requires EE services - like
servlet code, EJBs, etc - run on its thread(s); and
- We use a ServiceLoader in /META-INF/services to destroy it when the
JDBC driver is unloaded, the war
the JDBC driver is bundled in is undeployed or the app server is stopped;
That should provide the JDBC driver with a suitable timer mechanism.
Perhaps more excitingly, a generic ThreadPoolExecutor can be safely used
within an EE container the same way, potentially allowing the JDBC
driver to use threads for blocking I/O. That'd finally permit a version
of PgConnection.getNotifications() that can be safely invoked without
blocking when SSL is in use!
A driver thread pool could also help permanently fix those occasional
deadlocks that happen due to buffer management issues in the JDBC driver.
I'll try to find time to do some testing and see if I can make this work
or at least bash out a proof of concept.
--
Craig Ringer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-sql@postgresql.org
Cc: ringerc@ringerc.id.au, david@fetter.org, smougenot@sqli.com, pgsql-jdbc@postgresql.org
Subject: Re: [SQL] JDBC Statement.setQueryTimeout : is there plan to implement this?
In-Reply-To: <4EE97B85.50909@ringerc.id.au>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox