HI Shawn, Thanks for your reply.
The memory setting of my Solr box is 12G physically memory. 4G for java (-Xmx4096m) The index size is around 4G in Solr 4.9, I think it was over 6G in Solr 4.0. I do think the RAM size of java is one of the reasons for this slowness. I'm doing one big commit and when the ingestion process finished 50%, I can see the solr server already used over 90% of full memory. I'll try to assign more RAM to Solr Java. But from your experience, does 4G sounds like a good number for Java heap size for my scenario? Is there any way to reduce memory usage during index time? (One thing I know is do a few commits instead of one commit. ) My concern is providing I have 12 G in total, If I assign too much to Solr server, I may not have enough for the OS to cache Solr index file. I had a look to solr config file, but couldn't find anything that obviously wrong, Just wondering which part of that config file would impact the index time? Thanks, Ryan One possible source of problems with that particular upgrade is the fact that stored field compression was added in 4.1, and termvector compression was added in 4.2. They are on by default and cannot be turned off. The compression is typically fast, but with very large documents like yours, it might result in pretty major computational overhead. It can also require additional java heap, which ties into what follows: Another problem might be RAM-related. If your java heap is very large, or just a little bit too small, there can be major performance issues from garbage collection. Based on the fact that the earlier version performed well, a too-small heap is more likely than a very large heap. If your index size is such that it can't be effectively cached by the amount of total RAM on the machine (minus the java heap assigned to Solr), that can cause performance problems. Your index size is likely to be several gigabytes, and might even reach double-digit gigabytes. Can you relate those numbers -- index size, java heap size, and total system RAM? If you can, it would also be a good idea to share your solrconfig.xml. Here's a wiki page that goes into more detail about possible performance issues. It doesn't mention the possible compression problem: http://wiki.apache.org/solr/SolrPerformanceProblems Thanks, Shawn
