Likely this is for field norms, which use doc values under the hood. Mike McCandless
http://blog.mikemccandless.com On Thu, Dec 26, 2013 at 5:03 PM, Greg Preston <gpres...@marinsoftware.com> wrote: > Does anybody with knowledge of solr internals know why I'm seeing > instances of Lucene42DocValuesProducer when I don't have any fields > that are using DocValues? Or am I misunderstanding what this class is > for? > > -Greg > > > On Mon, Dec 23, 2013 at 12:07 PM, Greg Preston > <gpres...@marinsoftware.com> wrote: >> Hello, >> >> I'm loading up our solr cloud with data (from a solrj client) and >> running into a weird memory issue. I can reliably reproduce the >> problem. >> >> - Using Solr Cloud 4.4.0 (also replicated with 4.6.0) >> - 24 solr nodes (one shard each), spread across 3 physical hosts, each >> host has 256G of memory >> - index and tlogs on ssd >> - Xmx=7G, G1GC >> - Java 1.7.0_25 >> - schema and solrconfig.xml attached >> >> I'm using composite routing to route documents with the same clientId >> to the same shard. After several hours of indexing, I occasionally >> see an IndexWriter go OOM. I think that's a symptom. When that >> happens, indexing continues, and that node's tlog starts to grow. >> When I notice this, I stop indexing, and bounce the problem node. >> That's where it gets interesting. >> >> Upon bouncing, the tlog replays, and then segments merge. Once the >> merging is complete, the heap is fairly full, and forced full GC only >> helps a little. But if I then bounce the node again, the heap usage >> goes way down, and stays low until the next segment merge. I believe >> segment merges are also what causes the original OOM. >> >> More details: >> >> Index on disk for this node is ~13G, tlog is ~2.5G. >> See attached mem1.png. This is a jconsole view of the heap during the >> following: >> >> (Solr cloud node started at the left edge of this graph) >> >> A) One CPU core pegged at 100%. Thread dump shows: >> "Lucene Merge Thread #0" daemon prio=10 tid=0x00007f5a3c064800 >> nid=0x7a74 runnable [0x00007f5a41c5f000] >> java.lang.Thread.State: RUNNABLE >> at org.apache.lucene.util.fst.Builder.add(Builder.java:397) >> at >> org.apache.lucene.codecs.BlockTreeTermsWriter$TermsWriter.finishTerm(BlockTreeTermsWriter.java:1000) >> at >> org.apache.lucene.codecs.TermsConsumer.merge(TermsConsumer.java:112) >> at >> org.apache.lucene.codecs.FieldsConsumer.merge(FieldsConsumer.java:72) >> at >> org.apache.lucene.index.SegmentMerger.mergeTerms(SegmentMerger.java:365) >> at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:98) >> at >> org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:3772) >> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3376) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:405) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:482) >> >> B) One CPU core pegged at 100%. Manually triggered GC. Lots of >> memory freed. Thread dump shows: >> "Lucene Merge Thread #0" daemon prio=10 tid=0x00007f5a3c064800 >> nid=0x7a74 runnable [0x00007f5a41c5f000] >> java.lang.Thread.State: RUNNABLE >> at >> org.apache.lucene.codecs.DocValuesConsumer$1$1.hasNext(DocValuesConsumer.java:127) >> at >> org.apache.lucene.codecs.lucene42.Lucene42DocValuesConsumer.addNumericField(Lucene42DocValuesConsumer.java:144) >> at >> org.apache.lucene.codecs.lucene42.Lucene42DocValuesConsumer.addNumericField(Lucene42DocValuesConsumer.java:92) >> at >> org.apache.lucene.codecs.DocValuesConsumer.mergeNumericField(DocValuesConsumer.java:112) >> at >> org.apache.lucene.index.SegmentMerger.mergeNorms(SegmentMerger.java:221) >> at >> org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:119) >> at >> org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:3772) >> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3376) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:405) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:482) >> >> C) One CPU core pegged at 100%. Manually triggered GC. No memory >> freed. Thread dump shows: >> "Lucene Merge Thread #0" daemon prio=10 tid=0x00007f5a3c064800 >> nid=0x7a74 runnable [0x00007f5a41c5f000] >> java.lang.Thread.State: RUNNABLE >> at >> org.apache.lucene.codecs.DocValuesConsumer$1$1.hasNext(DocValuesConsumer.java:127) >> at >> org.apache.lucene.codecs.lucene42.Lucene42DocValuesConsumer.addNumericField(Lucene42DocValuesConsumer.java:108) >> at >> org.apache.lucene.codecs.lucene42.Lucene42DocValuesConsumer.addNumericField(Lucene42DocValuesConsumer.java:92) >> at >> org.apache.lucene.codecs.DocValuesConsumer.mergeNumericField(DocValuesConsumer.java:112) >> at >> org.apache.lucene.index.SegmentMerger.mergeNorms(SegmentMerger.java:221) >> at >> org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:119) >> at >> org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:3772) >> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3376) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:405) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:482) >> >> D) One CPU core pegged at 100%. Thread dump shows: >> "Lucene Merge Thread #0" daemon prio=10 tid=0x00007f5a3c064800 >> nid=0x7a74 runnable [0x00007f5a41c5f000] >> java.lang.Thread.State: RUNNABLE >> at >> org.apache.lucene.codecs.compressing.CompressingTermVectorsReader.get(CompressingTermVectorsReader.java:322) >> at >> org.apache.lucene.index.SegmentReader.getTermVectors(SegmentReader.java:169) >> at >> org.apache.lucene.codecs.compressing.CompressingTermVectorsWriter.merge(CompressingTermVectorsWriter.java:789) >> at >> org.apache.lucene.index.SegmentMerger.mergeVectors(SegmentMerger.java:312) >> at >> org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:130) >> at >> org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:3772) >> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3376) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:405) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:482) >> >> E) CPU usage drops to nominal levels. Thread dump shows no Lucene Merge >> Thread. >> >> F) Manually triggered full GC. Some memory freed, but much remains. >> >> G) Restarted solr. Very little memory used. >> >> >> Throughout all of this, there was no indexing or querying happening. >> In ordered to try to determine what's using up the memory, I took a >> heap dump at point (F) and analyzed it in Eclipse MAT (see attached >> screenshot). This shows 311 instances of Lucene42DocValuesProducer$3, >> each holding a large byte[]. By attaching a remote debugger and >> re-running, it looks like there is one of these byte[] for each field >> in the schema (we have several of the "dim_*" dynamic fields). And as >> far as I know, I'm not using DocValues at all. >> >> >> Any hints as to what might be going on here would be greatly >> appreciated. It takes me about 10 minutes to reproduce this, so I'm >> willing to try things. I don't know enough about the internals of >> solr's memory usage to proceed much further on my own. >> >> Thank you. >> >> -Greg
