Lucene中多值字段的性能问题

Question

We're using Lucene 4.7 to build and query a rather large data set (110+ millions documents).

One of the document field, which we used for faceting, is defined as follow:

<field name="topic_paths"
       type="string"
       indexed="false"
       stored="false"
       docValues="true"
       multiValued="true"
       termVectors="false"
       termPositions="false"
       termOffsets="false"/>

Whenever we include this field in queries, they become extremely slow: about 7 seconds per topic_path value included in the search, so about 30 seconds for four topic_path values (typical in our case).

Queries that don't use this field are very fast (15 ms).

Is this performance we should expect from Lucene with multi-valued fields used for faceting? Is there anything wrong or suboptimal with our field definition? Are there tricks we could use to speedup searches?

Details:

• Hardware: Xen VM, 8-core Xeon CPU E5-2670 v2 at 2.5 GHz, 64 GB RAM
• OS: Windows Server 2012 Standard
• JVM: started with -Xmx8000m (Lucene is using about 45% of that)
• Lucene queries are single-threaded

Answer 1

Read this article, http://wiki.apache.org/solr/SchemaXml#Fields

You need to "index" you field for including it into search/faceting, otherwise Solr will skipping this field without any exception