You should see better performance with -1 refresh_interval, because Lucene will flush larger, single segments, causing less merging pressure.
Are both of your tests (-1 vs 10s) fully saturating CPU and/or IO on your nodes? If not, then that can explain it: when you have 10s refresh_interval, a separate thread (refresh thread) bears the cost of moving the new segments to disk, but with -1, the bulk index threads themselves bear the cost. But if you test with enough client-side concurrency to saturate your resources you should see the opposite (-1 refresh_interval is faster indexing throughput). Mike McCandless On Mon, Apr 13, 2015 at 4:05 AM, Hajime <[email protected]> wrote: > Hi, > > I'm trying to improve the indexing performances.I follow these > instructions > > https://www.elastic.co/blog/performance-considerations-elasticsearch-indexing > > http://www.elastic.co/guide/en/elasticsearch/guide/master/indexing-performance.html > > and created 20 different indexes by changing translog,merge,refresh...etc > while "*number_of_shards:1,number_of_replica:0" part is common.* > I found that the best performed index was* actually **default settings > + refresh_interval:"10s"(not **refresh_interval:"-1") *in terms of doc > count accuracy or load average or lesser bulk queue*.* > > Can anyone explain why this settings is the best? > > In addition,I can observe when refresh thread is active,the segments count > decrease.What is exactly the refresh thread doing? > > thanks > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elasticsearch/CAHm3ZsrZNVJtOj__YO6enFqKDt4T1Hxi_pT94W9YQx7bNe%3Dg1g%40mail.gmail.com > <https://groups.google.com/d/msgid/elasticsearch/CAHm3ZsrZNVJtOj__YO6enFqKDt4T1Hxi_pT94W9YQx7bNe%3Dg1g%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/CAKHUQPiEsvcVdYdgYLK2PqkA7L-VGngTh-7kMDBXccz%3DkvD%2BjQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
