Hello, Apache Solr community members: I have a few questions about the load test of Solr8.
- for Solr8, optimization command merge segment to 2, but not 1. Is that ok behavior? When indexing Wikipedia data, Solr8 generated multiple segments. So, I executed <optimize /> command from the Admin UI. Solr8 did reduce the number of segments, but it left two segments. Hence, I wonder if it is ok behavior or it is weird. - in a certain situation (explained below), Solr8 (without the use of http/2 and block-max WAND algorithm) is faster then Solr7.4.0. What are the considerable causes of this performance improvement? Or did I plan load-test badly? Here is the story I came up with these questions. I performed a simple load test on Solr8 to observe the difference in performance. So, I wondered how fast it became, comparing to Solr7.4.0, which is the version I currently use. My testing environment is below: OS: Ubuntu 16.04 Vendor: DELL PowerEdge T410 CPU:Intel(R) Xeon(R) CPU E5620 @2.40 GHz 8 Core Memory: 16GB Hard Disk: 3.5 Inch SATA (7,200 rpm): 500 GB The data is from the Japanese Wikipedia dump. By indexing them, both versions of Solrs store 2'366'754 documents, which the index size and JVM memory are 8.48 GB and 8GB accordingly. In order to perform several times of load-tests, only fieldValueCache and fieldCache are working; other Solr's caches are turned off. I use Jmeter(5.1.1) to measure average response time and throughput. I know Jmeter only sends HTTP/1 requests, without a plugin. (and I did not use the plugin) So, this result should not be affected by HTTP/2. Also, according to a JIRA ( https://issues.apache.org/jira/browse/SOLR-13289 ). Solr8 has not supported block-max WAND algorithm yet, so again this result should not be affected by the algorithm, which makes Lucene faster. The results from Jmeter is attached as a PDF file. According to these results, Solr8 is somehow superior then Solr7.4.0. But, I have no idea what are the considerable causes of this difference. Does anyone have any idea about this? Sincerely, Kaya Ota
