Hi, I believe data is not fsynched to disk until a hard commit (and even then disks can lie to you and tell you data is safe even though it's still in disk cache waiting to really be written to the medium) , which is why you can lose it between hard commits. Soft commits just make newly added docs visible in search results.
Otis -- Solr & ElasticSearch Support -- http://sematext.com/ Performance Monitoring -- http://sematext.com/spm On Tue, Sep 24, 2013 at 7:51 AM, adfel70 <adfe...@gmail.com> wrote: > I am struggling to get a deep understanding of soft commit. > I have read Erick's post > <http://searchhub.org/2013/08/23/understanding-transaction-logs-softcommit-and-commit-in-sorlcloud/> > which helped me a lot with when and why we should call each type of commit. > But still, I cant understand what exactly happens when we call soft commit: > I mean, does the new data is flushed, fsynched, or hold in the RAM... ? > I tried to test it myself and I got 2 different behaviours: > a. If I just had 1 document that was added to the index, soft commit did not > cause index files to change. > b. If I had a big change (addition of about 100,000 docs, ~5MB tlog file), > calling the soft commit DID change the index files - so I guess that soft > commit caused fsynch. > > My conclusion is that soft commit always flushes the data, but because of > the implementation of NRTCachingDirectoryFactory, the data will be written > to the disk when its getting too big. > > Can some one please correct me? > > > > -- > View this message in context: > http://lucene.472066.n3.nabble.com/Soft-commit-and-flush-tp4091726.html > Sent from the Solr - User mailing list archive at Nabble.com.
