"The reason I asked about the Cache sizes is I had read that configuring the Cache sizes of Solr does not provide you enough benefits...."
Where is "somewhere"? Because this is simply wrong as a blanket statement. filterCache can have tremendous impact on query performance, depending on the how many fq clauses you typically use and their re-use rate, i.e. hit ratio. Not to mention its possible effects on faceting. documentCache is usually not as dramatic once you get past it being (max rows expected) * (num simultaneous users). However I have seen situations where having a very large documentCache results in impressive performance gains. queryResultCache will short-circuit search entirely when paging. Etc. Your results may be vary of course. Perhaps you're confusing the docValues discussion (where the OS's memory is used rather than Java heap) with the general cache discussion. Best, Erick On Fri, May 12, 2017 at 10:58 AM, Suresh Pendap <spen...@walmartlabs.com> wrote: > Hi Shawn, > Thanks for the reply, it is useful. The reason I asked about the Cache > sizes is I had read that configuring the Cache sizes of Solr does not > provide you enough benefits, instead it is better to provide a lot of > memory space to the Solr outside the JVM heap. > > Is it true that in general the strategy of using the OS buffer cache works > better instead of using a large Cache inside the JVM heap? > > I was looking for some numbers that people have used for configuring these > Caches in the past and the rational for choosing these values. > > Thanks > Suresh > > > On 5/11/17, 11:13 PM, "Shawn Heisey" <apa...@elyograg.org> wrote: > >>On 5/11/2017 4:58 PM, Suresh Pendap wrote: >>> This question might have been asked on the solr user mailing list >>>earlier. Solr has four different types of Cache DocumentCache, >>>QueryResultCache, FieldValueCache and FilterQueryCache >>> I would like to know which of these Caches are off heap cache? >> >>None of them are off-heap. For a while, there was a forked project >>called Heliosearch that did have a bunch of off-heap memory structures, >>but it is my understanding that Heliosearch is effectively dead now. >> >>There are at least three issues for bringing this capability to Solr, >>but none of them have been added yet. >> >>https://issues.apache.org/jira/browse/SOLR-6638 >>https://issues.apache.org/jira/browse/SOLR-7211 >>https://issues.apache.org/jira/browse/SOLR-7210 >> >>> Which Caches have the maximum impact on the query latency and it is >>>recommended to configure that Cache? >> >>This is so dependent on your exact index and your exact queries that >>nobody can give you a reliable answer to that question. >> >>The filterCache is pretty good at speeding things up when you have >>filter queries that get reused frequently, but depending on how your >>setup works, it might not provide the most impact. >> >>> I also would like to know if there is any document which provides >>>guidelines on performing Capacity planning for a Solr cluster. >> >>No. It's not possible to provide general information. See this: >> >>https://lucidworks.com/sizing-hardware-in-the-abstract-why-we-dont-have-a- >>definitive-answer/ >> >>Thanks, >>Shawn >> >
