[hibernate-dev] [infinispan-dev] Feedback on Infinispan patch

[Łukasz Moreń]

Hi,

Thanks for explanation.
Maybe better I will concentrate on the first release and postpone
distributed writing.

There is already LockStrategy that uses Infinispan. With using it I was
wrapping changes made by IndexWriter in Infinispan transaction, because of
performance reasons -
on lock obtaining transaction was started, on lock release transaction was
commited. Hovewer Ispn transaction commit on lock release is not good idea
since IndexWriter calls index commit before lock is released(and ispn
transaction is committed).
I was thinking to override Workspace class and getIndexWriter(start
infinispan tx), commitIndexWriter (commit tx) methods to wrap IndexWrite
lifecycle, but this needs few other changes. Some other ideas?

Cheers,
Lukasz

2009/9/21 Sanne Grinovero <sanne.grinovero at gmail.com>

> Hi Łukasz,
> you've rightful concerns, because the way the IndexWriter tries to
> achieve the lock
> that will bring some trouble; As far as I remember we decided in this
> first release
> to avoid multiple writer nodes because of this reasons
> (that's written in your docs?)
>
> Actually it shouldn't be very hard to do, as the LockStrategy is
> pluggable (see changes from HSEARCH-345)
> and you could implement one delegating to an Infinispan eager lock on some
> key,
> like the default LockStrategy takes a file lock in the index directory.
>
> Maybe it's simpler to support this distributed writing instead of
> sending the queue to some single
> (elected) node? Would be cool, as the Document Analysis effort would
> be distributed,
> but I have no idea if this would be more or less efficient than a
> single node writing; it could
> bring some huge data transfers along the wire during segments merging
> (basically fetching
> the whole index data at each node performing a segment merge); maybe
> you'll need to
> play with IndexWriter settings (
>
> http://docs.jboss.org/hibernate/stable/search/reference/en/html_single/#lucene-indexing-performance
> )
> probably need to find the sweet spot for "merge_factor".
> I just saw now that MergePolicy is now re-implementable, but I hope
> that won't be needed.
>
> Sanne
>
> 2009/9/21 Łukasz Moreń <lukasz.moren at gmail.com>:
> > Hi,
> >
> > I'm wondering if it is reasonable to have multiple threads/nodes that
> > modifies indexes in Lucene Directory based on Infinispan? Let's assume
> that
> > two nodes try to update index in this same time. First one creates
> > IndexWriter and obtains
> > write lock. There is high propability that second node throws
> > LockObtainFailedException (as one IndexWriter is allowed on single index)
> > and index is not modified. How is that? Should be always only one node
> that
> > makes changes in
> > the index?
> >
> > Cheers,
> > Lukasz
> >
> > W dniu 15 września 2009 01:39 użytkownik Łukasz Moreń
> > <lukasz.moren at gmail.com> napisał:
> >>
> >> Hi,
> >>
> >> With using JMeter I wanted to check if Infinispan dir does not crash
> under
> >> heavy load in "real" use and check performance in comparison with
> none/other
> >> directories.
> >> However appeared problem when multiple IndexWriters tries to modify
> index
> >> (test InfinispanDirectoryTest) - random deadlocks, and Lucene
> exceptions.
> >> IndexWriter tries to access files in index that were removed before. I'm
> >> looking into it, but not having good idea.
> >>
> >> Concerning the last part, I think similar thing is done in
> >> InfinispanDirectoryProviderTest. Many threads are making changes and
> >> searching (not checking if db is in sync with index).
> >> If threads finish their work, with Lucene query I'm checking if index
> >> contains as many results as expected. Maybe you meant something else?
> >> Would be good to run each node in different VM.
> >>
> >>> Great ! Looking forward to it. What state are things in at the moment
> >>> if I want to play around with it ?
> >>
> >> Should work with with one master(updates index) and one many slave nodes
> >> (sends changes to master). I tried with one master and one slave (both
> with
> >> jms and jgroups backend) and worked ok. Still fails if multiple nodes
> want
> >> to modify index.
> >>
> >> I've attached patch with current version.
> >>
> >> Cheers,
> >> Łukasz
> >>
> >> 2009/9/13 Michael Neale <michael.neale at gmail.com>
> >>>
> >>> Great ! Looking forward to it. What state are things in at the moment
> >>> if I want to play around with it ?
> >>>
> >>> Sent from my phone.
> >>>
> >>> On 13/09/2009, at 7:26 PM, Sanne Grinovero <sanne.grinovero at gmail.com>
> >>> wrote:
> >>>
> >>> > 2009/9/12 Michael Neale <michael.neale at gmail.com>:
> >>> >> That does sounds pretty cool. Would be nice if the lucene indexes
> >>> >> could scale along with how people will want to use infinispan.
> >>> >> Probably worth playing with.
> >>> >
> >>> > Sure, this is the goal of Łukasz's work; We know compass has
> >>> > some good Directories, but we're building our own as one based
> >>> > on Infinispan is not yet available.
> >>> >
> >>> >>
> >>> >> Sent from my phone.
> >>> >>
> >>> >> On 13/09/2009, at 8:37 AM, Jeff Ramsdale <jeff.ramsdale at gmail.com>
> >>> >> wrote:
> >>> >>
> >>> >>> I'm afraid I haven't followed the Infinispan-Lucene implementation
> >>> >>> closely, but have you looked at the Compass Project?
> >>> >>> (http://www.compass-project.org/overview.html) It provides a
> >>> >>> simplified interface to Lucene (optional) as well as Directory
> >>> >>> implementations built on Terracotta, Gigaspaces and Coherence. The
> >>> >>> latter, in particular, might be a useful guide for the Infinispan
> >>> >>> implementation. I believe it's mature enough to have solved many of
> >>> >>> the most difficult problems of implementing Directory on a
> >>> >>> distributed
> >>> >>> Map.
> >>> >>>
> >>> >>> If someone has any experience with Compass (particularly it's
> >>> >>> Directory implementations) I'd be interested in hearing about it...
> >>> >>> It's Apache 2.0 licensed, btw.
> >>> >>>
> >>> >>> -jeff
> >>> >>> _______________________________________________
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> >>> >>
> >>> >
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> >>>
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> >
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>
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