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
