[SOLR-11196] Solr 6.5.0 consuming entire Heap suddenly while working smoothly on Solr 6.1.0

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 6.5, 6.6
• Assignee: Unassigned
• Reporter: Amit
• Created: 04/Aug/17 13:58
• Updated: 08/Jun/19 15:20
• Resolved: 28/Mar/19 17:51

Description

Please note, this issue does not occurs on Solr-6.1.0 while the same occurs on Solr-6.5.0 and above. To fix this we had to move back to Solr-6.1.0 version.

We have been hit by a Solr Behavior in production which we are unable to debug. To start with here are the configurations for solr:

Solr Version: 6.5, Master with 1 Slave of the same configuration as mentioned below.

JVM Config:

     -Xms2048m
     -Xmx4096m
     -XX:+ParallelRefProcEnabled
     -XX:+UseCMSInitiatingOccupancyOnly
     -XX:CMSInitiatingOccupancyFraction=50

Rest all are default values.

Solr Config :

   <autoCommit>
      <!-- Auto hard commit in 5 minutes -->
      <maxTime>{solr.autoCommit.maxTime:300000}</maxTime>
      <openSearcher>false</openSearcher>
    </autoCommit>
    <autoSoftCommit>
    <!-- Auto soft commit in 15 minutes -->
      <maxTime>{solr.autoSoftCommit.maxTime:900000}</maxTime>
    </autoSoftCommit>
    </updateHandler>

    <query>
      <maxBooleanClauses>1024</maxBooleanClauses>
      <filterCache class="solr.FastLRUCache" size="8192" initialSize="8192" autowarmCount="0" />
      <queryResultCache class="solr.LRUCache" size="8192" initialSize="4096" autowarmCount="0" />
      <documentCache class="solr.LRUCache" size="12288" initialSize="12288" autowarmCount="0" />
      <cache name="perSegFilter" class="solr.search.LRUCache" size="10" initialSize="0" autowarmCount="10" regenerator="solr.NoOpRegenerator" />
      <enableLazyFieldLoading>true</enableLazyFieldLoading>
      <queryResultWindowSize>20</queryResultWindowSize>
      <queryResultMaxDocsCached>${solr.query.max.docs:40}
      </queryResultMaxDocsCached>
      <useColdSearcher>false</useColdSearcher>
      <maxWarmingSearchers>2</maxWarmingSearchers>
    </query>

The Host (AWS) configurations are:

RAM: 7.65GB
Cores: 4

Now, our solr works perfectly fine for hours and sometimes for days but sometimes suddenly memory jumps up and the GC kicks in causing long big pauses with not much to recover. We are seeing this happening most often when one or multiple segments gets added or deleted post a hard commit. It doesn't matter how many documents got indexed. The images attached shows that just 1 document was indexed, causing an addition of one segment and it all got messed up till we restarted the Solr.

Here are the images from NewRelic and Sematext (Kindly click on the links to view):

JVM Heap Memory Image
1 Document and 1 Segment addition Image

Update: Here is the JMap output when SOLR last died, we have now increased the JVM memory to xmx of 12GB:

 num     #instances         #bytes  class name
  ----------------------------------------------
  1:      11210921     1076248416  org.apache.lucene.codecs.lucene50.Lucene50PostingsFormat$IntBlockTermState
  2:      10623486      934866768  [Lorg.apache.lucene.index.TermState;
  3:      15567646      475873992  [B
  4:      10623485      424939400  org.apache.lucene.search.spans.SpanTermQuery$SpanTermWeight
  5:      15508972      372215328  org.apache.lucene.util.BytesRef
  6:      15485834      371660016  org.apache.lucene.index.Term
  7:      15477679      371464296  org.apache.lucene.search.spans.SpanTermQuery
  8:      10623486      339951552  org.apache.lucene.index.TermContext
  9:       1516724      150564320  [Ljava.lang.Object;
 10:        724486       50948800  [C
 11:       1528110       36674640  java.util.ArrayList
 12:        849884       27196288  org.apache.lucene.search.spans.SpanNearQuery
 13:        582008       23280320  org.apache.lucene.search.spans.SpanNearQuery$SpanNearWeight
 14:        481601       23116848  org.apache.lucene.document.FieldType
 15:        623073       19938336  org.apache.lucene.document.StoredField
 16:        721649       17319576  java.lang.String
 17:         32729        7329640  [J
 18:         14643        5788376  [F

The load on Solr is not much - max it goes to 2000 requests per minute. The indexing load can sometimes be in burst but most of the time its pretty low. But as mentioned above sometimes even a single document indexing can put solr into tizzy and sometimes it just works like a charm.

Edit :

The last configuration on which 6.1 works but not 6.5 is:
JVM Config:

     Xms: 2 GB
     Xmx: 12 GB

Solr Config:
We also removed soft commit.

  <autoCommit>
   <!-- Auto hard commit in 5 minutes -->
   <maxTime>${solr.autoCommit.maxTime:300000}</maxTime>
   <openSearcher>true</openSearcher>
  </autoCommit>

The Host (AWS) configurations:
RAM: 16GB
Cores: 4