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From Shawn Heisey <>
Subject Re: Disable transaction log with SOLRCloud without replicas
Date Wed, 15 Jul 2015 19:28:23 GMT
On 7/15/2015 12:42 PM, SolrUser1543 wrote:
> from here :
> we can learn that Transaction Log is needed when replicas are used in SOLR
> cloud . 
> Do I need it if I am not using a replicas ?
> Could it be disabled for performance improvement ?  
> What are negative influence may be in this case ?  

Have you benchmarked performance with and without the log to see how
much faster it actually is?  I'm sure it's faster, but unless your
documents are particularly large, I doubt it's a LOT faster, and you may
lower your reliability.

Unless it's causing you problems, it's a good idea to have that feature
enabled.  You can keep transaction log size under control (with no
change in searcher functionality) by simply configuring autoCommit with
a short maxTime (five minutes or less) and openSearcher=false.

If you want the log disabled, you might want to also consider changing
your directoryFactory in solrconfig.xml from the default
NRTCachingDirectoryFactory to MMapDirectoryFactory, so you can be
absolutely sure that all commits are flushed to disk and not cached in RAM.


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