Re: Solr heap Old generation grows and it is not recovered by G1GC

[Odysci]

Hi Furkan,

I'm using solr 8.3.1 (with openjdk version "11.0.7"),  with the following
cache settings:

    <filterCache class="solr.CaffeineCache"

                 size="8192"

                 initialSize="512"

                 maxRamMB="512"

                 autowarmCount="128"/>


   <queryResultCache class="solr.CaffeineCache"

                      size="8192"

                      initialSize="1024"

                      maxRamMB="256"

                      autowarmCount="128"/>


   <documentCache class="solr.CaffeineCache"

                   size="16384"

                   initialSize="1024"

                   maxRamMB="1280"

                   autowarmCount="0"/>



   <fieldValueCache class="solr.CaffeineCache"

                     size="64"

                     autowarmCount="128"

                     showItems="32" />


Thanks
Reinaldo

On Thu, Jun 25, 2020 at 7:45 PM Furkan KAMACI <furkankam...@gmail.com>
wrote:

> Hi Reinaldo,
>
> Which version of Solr do you use and could you share your cache settings?
>
> On the other hand, did you check here:
> https://cwiki.apache.org/confluence/display/SOLR/SolrPerformanceProblems
>
> Kind Regards,
> Furkan KAMACI
>
> On Thu, Jun 25, 2020 at 11:09 PM Odysci <ody...@gmail.com> wrote:
>
> > Hi,
> >
> > I have a solrcloud setup with 12GB heap and I've been trying to optimize
> it
> > to avoid OOM errors. My index has about 30million docs and about 80GB
> > total, 2 shards, 2 replicas.
> >
> > In my testing setup I submit multiple queries to solr (same node),
> > sequentially, and with no overlap between the documents returned in each
> > query (so docs do not need to be kept in cache)
> >
> > When the queries return a smallish number of docs (say, below 1000), the
> > heap behavior seems "normal". Monitoring the gc log I see that young
> > generation grows then when GC kicks in, it goes considerably down. And
> the
> > old generation grows just a bit.
> >
> > However, at some point i have a query that returns over 300K docs (for a
> > total size of approximately 1GB). At this very point the OLD generation
> > size grows (almost by 2GB), and it remains high for all remaining time.
> > Even as new queries are executed, the OLD generation size does not go
> down,
> > despite multiple GC calls done afterwards.
> >
> > Can anyone shed some light on this behavior?
> >
> > I'm using the following GC options:
> > GC_TUNE=" \
> >
> > -XX:+UseG1GC \
> >
> > -XX:+PerfDisableSharedMem \
> >
> > -XX:+ParallelRefProcEnabled \
> >
> > -XX:G1HeapRegionSize=4m \
> >
> > -XX:MaxGCPauseMillis=250 \
> >
> > -XX:InitiatingHeapOccupancyPercent=75 \
> >
> > -XX:+UseLargePages \
> >
> > -XX:+AggressiveOpts \
> >
> > "
> > Thanks
> > Reinaldo
> >
>