On Tue, 2019-09-03 at 12:35 -0700, Russell Bahr wrote: > Also, if it helps, the content on each server is between around 6.2Gb > and 7.8Gb.
We're still missing something here. The trivial query http://solr.obscured.com:8990/solr/content/select?q=*%3A*&wt=json&indent=true on such a modest index size & document count should not take seconds to complete. So we must widen our questioning: * What is your Xmx for the Solrs? (If you use most of the physical memory for Java, there might be too little left for OS-caching) * Do you have a large number of stored or docValued fields? (Solr 8 returns docValued fields per default while Solr 4 does not) * How large is a response? One simple way to check is curl ' http://solr.obscured.com:8990/solr/content/select?q=*%3A*&wt=json&indent=true' | wc -c (Solr 4 and 8 compress stored content differently and a very large result set requires more CPU power to uncompress in Solr 8 (but less IO)) * Do you have any response related defaults in your solrconfig.xml, such as faceting or grouping? (You might be doing heavy aggregation even if you don't explicitly ask for it) - Toke Eskildsen, Royal Danish Library
