Before we implemented the CommonGrams Index, our slowest query with the standard index was “the lives and literature of the beat generation” which took about 2 minutes for the 500,000 volume index. When we implemented the CommonGrams index, that query took only 3.6 seconds.
In part 1 we talked about why some queries are slow and the effect of these slow queries on overall performance. The slowest queries are phrase queries containing common words. These queries are slow because the size of the positions index for common terms on disk is very large and disk seeks are slow. These long positions index entries cause three problems relating to overall response time:
This is a brief note on the current hardware and software environment we are using for Solr testing.
- Two Dell PowerEdge 1950 blades
- 2 x Dual Core Intel Xeon 3.0 GHz 5160 Processors
- 8GB - 32GB RAM depending on the test configuration
- Red Hat Enterprise Linux 5.3 (kernel: 2.6.18 PAE)
- Java(TM) SE Runtime Environment (build: 1.6.0_11-b03)
- Solr 1.3
- Tomcat 5.5.26
All Queries are not created equal
Since we finished the work described in the Large Scale Search Report we have made some changes to our test protocol and upgraded our Solr implementions to Solr 1.3. We have completed some testing with increased memory and some preliminary load testing.
The new test protocol has these features