When I upgraded from 3.2 to 3.6, I found that an optimize - all other variables being the same - took about twice as long. Eventually I was able to track this down to the new default of MMapDirectory. By changing back to NIOFSDirectory, I was able to get the optimize time back down to what it formerly was. I did this by adding this to solrconfig.xml: <directoryFactory name="DirectoryFactory" class="solr.NIOFSDirectoryFactory"/>
I'd suggest trying that to see what effect it has (for us, NIOFSDirectory generally performs better across the board, but I've heard just the opposite from other people on this mailing list). If that doesn't improve it, try looking at these things: 1) Is the size of the index files the same size as in 1.4? Perhaps something has changed to cause a significant size increase. 2) Is Solr 4 spending more time garbage collecting? Enable gc logging with -verbose:gc (or whatever the flag is), or use the jstat utility. 3) Watch the files in the index directory during the optimize and see if they are being written more slowly, or if the segment files are being "copied" around more often than before. -Michael -----Original Message----- From: Sandeep Mestry [mailto:sanmes...@gmail.com] Sent: Tuesday, December 04, 2012 6:29 PM To: solr-user@lucene.apache.org Subject: Solr 4 : Optimize very slow Hi All, I have recently migrated from solr 1.4 to solr 4 and have done the basic changes required for solr 4 in solrconfig.xml and schema.xml. I have also rebuilt the index set for solr 4. We run optimize every morning at 4 am and we keep the index updates off during this process. Previously, with 1.4 - the optimization used to take around 20-30 mins per shard but now with solr 4, its taking 6-8 hours or even more.. I have also tested the optimize from solr UI and that takes 6-8 hours too.. The hardware is saeme and, we have deployed solr under WAS. There ar 4 shards and every shard contains around 8 - 9 Gig of data and we are using master-slave configuration with rsync. I have not enabled soft commit. Also, commiter process is scheduled to run every minute. I am not sure which part I'm missing, do let me know your inputs please. Many Thanks in advance, Sandeep
