mergeFactor and maxMergeDocs

["Chong, Herb" <HC...@bloomberg.com>]

what effect and what recommendations are valid for Lucene 1.3?

Herb....

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Re: mergeFactor and maxMergeDocs

[Doug Cutting <cu...@apache.org>]

Chong, Herb wrote:
> what effect and what recommendations are valid for Lucene 1.3?

Same as always: use the defaults and call optimize() only when you know 
you won't be changing the index for a while.

If you have lots of RAM, increasing minMergeDocs may increase indexing 
speed, but raising it too high may cause out of memory problems.

You may also see some indexing speedup by increasing the mergeFactor, 
but raising it too high will cause file handle problems.  Calling 
setUseCompoundFile() will enable higher mergeFactor settings before 
encountering file handle problems.

Obsession with indexing performance is not healthy.  Before changing any 
settings convince yourself that indexing performance is a real problem 
for your application.  How often do you re-index from scratch?  Are you 
really having any difficulty keeping up with the rate of change of your 
collection?  Perhaps your development time would be better spent 
focussing on other parts of your application.

Doug


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