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Date: Sun, 9 Aug 2009 14:30:45 -0700
Message-ID: <142154980908091430u6ceb7e88k66f79de8c909906a@mail.gmail.com>
Subject: Severe QTime issues to do with updates
From: Kaktu Chakarabati <jimmoefoe@gmail.com>
To: solr-dev@lucene.apache.org
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Hey,
I've recently noticed that there is a very large spike in the QTime for
nodes serving queries, immediately after snappulling and snapinstalling.
The numbers i'm seeing there are obviously some kind of
lock-contention/concurrency issue, as I've monitored iostat/sar and its not
a disk IO
issue ( all the index is still mostly in the os caches, as is also
noticeable in the snappuller.log which runs very fast - the incremental
update to the
lucene index is minimal).
I'm using a strong machine (16GB 2xQuadCore, CentOS5) for this and from all
monitoring the CPU/Disk IO seems minimal through-out the day.
The update runs every 10 minutes, takes about 200seconds to complete (with
my current autoWarm settings)., and the index size
is about 20million documents (~6GB). queries/warmup involve mostly some
pre-fixed set of filters and facets.

I'm using a nightly build of solr from few months back ( nightly exported -
yonik - 2009-01-11 08:05:52 )  which should already have
the benefits of readonlyindexreader, NIOFS, UnInvertedIndex and
ConcurrentLRUCache (for filterCache).
I've read a related thread a guy called oleg posted (
http://mail-archives.apache.org/mod_mbox/lucene-solr-user/200901.mbox/%3C339777.57289.qm@web50307.mail.re2.yahoo.com%3E)
, but did not see the thread concluded with any definite conclusion.

Please advise!

Best regards,
-Chak

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