es节点堆内存溢出：BlockTreeTermsWriter$PendingBlock.compileIndex

saas集群10各节点环境。7个数据节点。
最近集群经常有节点堆内存溢出，每次移除的原因都和以下日志有关系：
[2019-09-25T00:10:06,811][ERROR][o.e.i.e.Engine ] [node-6] [qtevent_2019.09.24_v1][7] merge failed
java.lang.OutOfMemoryError: Java heap space
at org.apache.lucene.util.fst.BytesStore.writeByte(BytesStore.java:89) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.util.fst.FST.<init>(FST.java:265) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.util.fst.Builder.<init>(Builder.java:157) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.blocktree.BlockTreeTermsWriter$PendingBlock.compileIndex(BlockTreeTermsWriter.java:456) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.blocktree.BlockTreeTermsWriter$TermsWriter.writeBlocks(BlockTreeTermsWriter.java:633) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.blocktree.BlockTreeTermsWriter$TermsWriter.pushTerm(BlockTreeTermsWriter.java:905) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.blocktree.BlockTreeTermsWriter$TermsWriter.write(BlockTreeTermsWriter.java:869) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.blocktree.BlockTreeTermsWriter.write(BlockTreeTermsWriter.java:343) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.FieldsConsumer.merge(FieldsConsumer.java:105) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.codecs.perfield.PerFieldPostingsFormat$FieldsWriter.merge(PerFieldPostingsFormat.java:164) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.index.SegmentMerger.mergeTerms(SegmentMerger.java:231) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 -jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:116) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4482) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:4077) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:625) ~[lucene-core-7.7.0.jar:7.7.0 8c831daf4eb41153c25ddb152501ab5bae3ea3d5 - jimczi - 2019-02-04 23:16:28]
at org.elasticsearch.index.engine.ElasticsearchConcurrentMergeScheduler.doMerge(ElasticsearchConcurrentMergeScheduler.java:101) ~[elasticsearch-6.8.0.jar:6.8.0]