[seam-dev] InitialContext performance issues
gavin at hibernate.org
Tue Sep 30 16:56:05 EDT 2008
Jay, I'm not disputing your suggestion.
On Tue, Sep 30, 2008 at 2:51 PM, Jay Balunas <tech4j at gmail.com> wrote:
> oh - I'm not saying this is the biggest part of the IntialContext blocks.
> The largest by far is all the calls to "lookup". This was just the first
> one that I pinned down, and seemed like an easy fix. I'm looking at the
> lookup calls, and will post more on it.
> FYI - When I profiled with the patch I included the block simply moved
> farther down into the InitialContext creation code. So a real fix would be
> limiting the number of instantiations, but as you say it might not be worth
> the effort. We'll have to see once we have optimized else where.
> On Tue, Sep 30, 2008 at 4:37 PM, Gavin King <gavin at hibernate.org> wrote:
>> Good work, Jay. I'm surprised to find that this is an issue. Really,
>> creation of
>> an InitialContext should be very lightweight (it should be optimized by
>> appserver). But if it's not, then Seam should optimize it.
>> On Tue, Sep 30, 2008 at 2:01 PM, Jay Balunas <tech4j at gmail.com> wrote:
>> > I have been looking more into the InitialContext and some of the
>> > performance
>> > issues surrounding it.
>> > There are really a couple of things to look at. One is how the
>> > InitialContext is created, and manged, and the other broad category is
>> > how
>> > often and what items are looked up? I have investigated the first, and
>> > have
>> > begun investigating the second.
>> > InitialContext creation and management
>> > ------------------------------------------------
>> > The only location were seam creates and manages the InitialContext is
>> > the
>> > "org.jboss.seam.util.Naming" class (see:
>> > http://fisheye.jboss.org/browse/Seam/trunk/src/main/org/jboss/seam/util/Naming.java?r=5444
>> > ).
>> > The properties are set in one location and done only once in the
>> > initialization of seam (see:
>> > http://fisheye.jboss.org/browse/Seam/trunk/src/main/org/jboss/seam/init/Initialization.java?r=9116#l915
>> > ).
>> > I see two issues here - one is creating the initial context every single
>> > time it is needed, and the other is processing/checking the properties
>> > every
>> > time it is called.
>> > The first issue would require some caching mechanism or logic for reuse.
>> > I
>> > am not an expert on when it makes sense to reuse an instance of the
>> > InitialContext, and when we need to get it fresh. I can say that we
>> > currently use they exact same properties to initialize it and those are
>> > set
>> > during Seam initialization and do not appear to ever change once
>> > created.
>> > Is there a way to cache and optimize this instantiation?
>> > The second issue is that we do a certain amount of processing every time
>> > the
>> > context is requested, this could be optimized. Currently I see a few
>> > blocked threads on the "props.size()" call in the Naming class which is
>> > a
>> > synchronized method on the Hashtable. This could easily be avoided.
>> > Although we need to maintain the logic that if the property list is
>> > empty we
>> > continue to call "new InitialContext()" and not pass in the properties
>> > object. This is because the first thing the InitialContext constructor
>> > does
>> > with a properties object is clone it which can be costly. I have
>> > attached a
>> > patch that implements these changes for review.
>> > Another item I noticed is that the only place (excluding some test code)
>> > that does not use "Naming.getInitialContext()" is the
>> > "org.jboss.seam.remoting.messaging.JBossConnectionProvider". It using
>> > the
>> > "new InitialContext()" directly. Shane - is there a reason for this?
>> > I'll write up my findings on the lookup usage asap.
>> > Thanks,
>> > Jay
>> > --
>> > blog: http://in.relation.to/Bloggers/Jay
>> > _______________________________________________
>> > seam-dev mailing list
>> > seam-dev at lists.jboss.org
>> > https://lists.jboss.org/mailman/listinfo/seam-dev
>> Gavin King
>> gavin.king at gmail.com
> blog: http://in.relation.to/Bloggers/Jay
gavin.king at gmail.com
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