Hello all,
Are there any general guidelines for determining the main factors in memory use
during merges?
We recently changed our indexing configuration to speed up indexing but in the
process of doing a very large merge we are running out of memory.
Below is a list of the changes and part of the indexwriter log. The changes
increased the indexing though-put by almost an order of magnitude.
(about 600 documents per hour to about 6000 documents per hour. Our documents
are about 800K)
We are trying to determine which of the changes to tweak to avoid the OOM, but
still keep the benefit of the increased indexing throughput
Is it likely that the changes to ramBufferSizeMB are the culprit or could it be
the mergeFactor change from 10-20?
Is there any obvious relationship between ramBufferSizeMB and the memory
consumed by Solr?
Are there rules of thumb for the memory needed in terms of the number or size
of segments?
Our largest segments prior to the failed merge attempt were between 5GB and
30GB. The memory allocated to the Solr/tomcat JVM is 10GB.
Tom Burton-West
-----------------------------------------------------------------
Changes to indexing configuration:
mergeScheduler
before: serialMergeScheduler
after: concurrentMergeScheduler
mergeFactor
before: 10
after : 20
ramBufferSizeMB
before: 32
after: 320
excerpt from indexWriter.log
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: LMP: findMerges: 40 segments
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: LMP: level 7.23609 to 7.98609: 20 segments
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: LMP: 0 to 20: add this merge
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: LMP: level 5.44878 to 6.19878: 20 segments
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: LMP: 20 to 40: add this merge
...
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: applyDeletes
Dec 14, 2010 5:34:10 PM IW 0 [Tue Dec 14 17:34:10 EST 2010;
http-8091-Processor70]: DW: apply 1320 buffered deleted terms and 0 deleted
docIDs and 0 deleted queries on 40 segments.
Dec 14, 2010 5:48:17 PM IW 0 [Tue Dec 14 17:48:17 EST 2010;
http-8091-Processor70]: hit exception flushing deletes
Dec 14, 2010 5:48:17 PM IW 0 [Tue Dec 14 17:48:17 EST 2010;
http-8091-Processor70]: hit OutOfMemoryError inside updateDocument
tom
