Thanks again Folks. I tried each suggestion and none made any difference. I am setting up a lab for performance monitoring using App Dynamics. Hopefully I am able to figure out something.
On Mon, Nov 28, 2016 at 11:20 AM, Erick Erickson <erickerick...@gmail.com> wrote: > bq: If you know the maximum size you ever will need, setting Xmx is good. > > Not quite sure what you're getting at here. I pretty much guarantee that a > production system will eat up the default heap size, so not setting Xmx > will > cause OOM errors pretty soon. Or did you mean Xms? > > As far as setting Xms, there are differing opinions, mostly though since > Solr > likes memory so much there's a lot of tuning to try to determine Xmx and > it's pretty much guaranteed that Java will need close to that amount of > memory. > So setting Xms=Xmx is a minor optimization if that assumption is true. > It's arguable > how much practical difference it makes though. > > Best, > Erick > > On Mon, Nov 28, 2016 at 2:14 AM, Florian Gleixner <f...@redflo.de> wrote: > > Am 28.11.2016 um 00:00 schrieb Shawn Heisey: > >> > >> On 11/27/2016 12:51 PM, Florian Gleixner wrote: > >>> > >>> On 22.11.2016 14:54, Max Bridgewater wrote: > >>>> > >>>> test cases were exactly the same, the machines where exactly the same > >>>> and heap settings exactly the same (Xms24g, Xmx24g). Requests were > >>>> sent with > >>> > >>> Setting heap too large is a common error. Recent Solr use the > >>> filesystem cache, so you don't have to set heap to the size of the > >>> index. The avalible RAM has to be able to run the OS, run the jvm and > >>> hold most of the index data in filesystem cache. If you have 32GB RAM > >>> and a 20GB Index, then set -Xms never higher than 10GB. I personally > >>> would set -Xms to 4GB and omit -Xmx > >> > >> > >> In my mind, the Xmx setting is much more important than Xms. Setting > >> both to the same number avoids any need for Java to detect memory > >> pressure before increasing the heap size, which can be helpful. > >> > > > > From https://cwiki.apache.org/confluence/display/solr/JVM+Settings > > > > "The maximum heap size, set with -Xmx, is more critical. If the memory > heap > > grows to this size, object creation may begin to fail and throw > > OutOfMemoryException. Setting this limit too low can cause spurious > errors > > in your application, but setting it too high can be detrimental as well." > > > > you are right, Xmx is more important. But setting Xms to Xmx will waste > RAM, > > that the OS can use to cache your index data. Setting Xmx can avoid > problems > > in some situations where solr can eat up your filesystem cache until the > > next GC has been finished. > > > >> Without Xmx, Java is in control of the max heap size, and it may not > >> make the correct choice. It's important to know what your max heap is, > >> because chances are excellent that the max heap *will* be reached. Solr > >> allocates a lot of memory to do its job. > >> > > > > If you know the maximum size you ever will need, setting Xmx is good. > > > > > > > > >
