Skimmed this, but yes, docs are durable thanks to transaction log that can replay on start.
Otis Solr & ElasticSearch Support http://sematext.com/ On Mar 13, 2014 8:25 PM, "shushuai zhu" <ss...@yahoo.com> wrote: > Hi, > > I noticed the following post indicating that Solr could recover > not-committed data from operational log: > > > http://www.opensourceconnections.com/2013/04/25/understanding-solr-soft-commits-and-data-durability/ > > which contradicts with Solr's web site: > > https://cwiki.apache.org/confluence/display/solr/Near+Real+Time+Searching > > that seems to indicate that data soft-committed before the last > hard-commit is lost. > > I reproduced what the author did in the first post (the two lessons he > listed) with Solr 4.7, and specifically compared below two experiments: > > I posted some records to Solr without commit > I could not view the records on browser after that since I set soft-commit > in 5 seconds > After 5 seconds, I can view the records on browser > Hard commit still does not happen since I set it in 60 seconds > Kill the Solr with a kill -9 <processId> > Keep the log file > Re-start the Solr > I could see the records via browser > > I think the hard-commit does not happen in the above experiment, since in > a different experiment, I got: > > I posted some records to Solr without commit > I could not view the records on browser after that since I set soft-commit > in 5 seconds > After 5 seconds, I can view the records on browser > Hard commit still does not happen since I set it in 60 seconds > Kill the Solr with a kill -9 <processId> > Remove the log file > Re-start the Solr > I could NOT see the records via browser > > This means Solr supports some database-like recovery (based on log). So, > as long as the log exists, after a crash, Solr can still recover from the > log. > > Any comments or idea? > > Thanks. > > Shushuai >
