There are a few bugs for which you require to merge the index, see SOLR-8807 and related bugs.
https://issues.apache.org/jira/browse/SOLR-8807 -----Original message----- > From:Erick Erickson <erickerick...@gmail.com> > Sent: Wednesday 3rd October 2018 4:50 > To: solr-user <solr-user@lucene.apache.org> > Subject: Re: Opinions on index optimization... > > The problem you're at now is that, having run optimize, that single > massive segment will accumulate deletes until it has < 2.5G "live" > documents. So once you do optimize (and until you get to Solr 7.5), > unless you can live with this one segment accumulating deletes for a > very long time, you must continue to optimize. > > Or you could re-index from scratch if possible and never optimize. > > Best, > Erick > On Tue, Oct 2, 2018 at 7:28 AM Walter Underwood <wun...@wunderwood.org> wrote: > > > > Don’t optimize. The first article isn’t as clear as it should be. The > > important sentence is "Unless you are running into resource problems, it’s > > best to leave merging alone.” > > > > I’ve been running Solr in production since version 1.3, with several > > different kinds and sizes of collections. I’ve never run a daily optimize, > > even on collections that only change once per day. > > > > The section titles "What? I can’t afford 50% “wasted” space” should have > > just been “Then don’t run Solr”. Really, you should have 100% free sapce, > > so a 22 Gb index would be on a volume with 22 Gb of free space. > > > > It was a mistake to name it “optimize”. It should have been “force merge”. > > > > wunder > > Walter Underwood > > wun...@wunderwood.org > > http://observer.wunderwood.org/ (my blog) > > > > > On Oct 2, 2018, at 6:04 AM, Jeff Courtade <courtadej...@gmail.com> wrote: > > > > > > We run an old master/slave solr 4.3.0 solr cluster > > > > > > 14 nodes 7/7 > > > indexes average 47/5 gig per shard around 2 mill docs per shard. > > > > > > We have constant daily additions and a small amount of deletes. > > > > > > We optimize nightly currently and it is a system hog. > > > > > > Is it feasible to never run optimize? > > > > > > I ask because it seems like it would be very bad not to but this > > > information is out there apparently recommending exactly that... never > > > optimizing. > > > > > > https://lucidworks.com/2017/10/13/segment-merging-deleted-documents-optimize-may-bad/ > > > > > > https://lucidworks.com/2018/06/20/solr-and-optimizing-your-index-take-ii/ > > > > > > https://wiki.apache.org/solr/SolrPerformanceFactors#Optimization_Considerations > > >
