Hi, I can't answer the question as to what the optimal size of rows per request is. I would expect it to depend on the number of stored fields being marshaled, and their type, and your hardware.
But using start + rows is a *bad thing* for deep paging. You need to use cursorMark, which looks like it was added in 4.7 originally https://issues.apache.org/jira/browse/SOLR-5463 There's a description on the newer reference guide https://lucene.apache.org/solr/guide/6_6/pagination-of-results.html#fetching-a-large-number-of-sorted-results-cursors and in the 4.10 PDF on page 305 https://archive.apache.org/dist/lucene/solr/ref-guide/apache-solr-ref-guide-4.10.pdf http://yonik.com/solr/paging-and-deep-paging/ On Fri, 10 Apr 2020 at 19:05, Mark H. Wood <mw...@iupui.edu> wrote: > I need to pull a *lot* of records out of a core, to be statistically > analyzed and the stat.s presented to the user, who is sitting at a > browser waiting. So far I haven't seen a way to calculate the stat.s > I need in Solr itself. It's difficult to know the size of the total > result, so I'm running the query repeatedly and windowing the results > with 'start' and 'rows'. I just guessed that a window of 1000 > documents would be reasonable. We currently have about 48GB in the > core. > > The product uses Solr 4.10. Yes, I know that's very old. > > What I got is that every three seconds or so I get another 1000 > documents, totalling around 500KB per response. For a user request > for a large range, this is taking way longer than the user's browser > is willing to wait. The single CPU on my test box is at 99% > continuously, and Solr's memory use is around 90% of 8GB. The test > hardware is a VMWare guest on an 'Intel(R) Xeon(R) Gold 6150 CPU @ > 2.70GHz'. > > A sample query: > > 0:0:0:0:0:0:0:1 - - [10/Apr/2020:13:34:18 -0400] "GET > /solr/statistics/select?q=*%3A*&rows=1000&fq=%2Btype%3A0+%2BbundleName%3AORIGINAL+%2Bstatistics_type%3Aview&fq=%2BisBot%3Afalse&fq=%2Btime%3A%5B2018-01-01T05%3A00%3A00Z+TO+2020-01-01T04%3A59%3A59Z%5D&sort=time+asc&start=867000&wt=javabin&version=2 > HTTP/1.1" 200 497475 "-" > "Solr[org.apache.solr.client.solrj.impl.HttpSolrServer] 1.0" > > As you can see, my test was getting close to 1000 windows. It's still > going. I don't know how far along that is. > > So I'm wondering: > > o how can I do better than guessing that 1000 is a good window size? > How big a response is too big? > > o what else should I be thinking about? > > o given that my test on a full-sized copy of the live data has been > running for an hour and is still going, is it totally impractical > to expect that I can improve the process enough to give a response > to an ad-hoc query while-you-wait? > > -- > Mark H. Wood > Lead Technology Analyst > > University Library > Indiana University - Purdue University Indianapolis > 755 W. Michigan Street > Indianapolis, IN 46202 > 317-274-0749 > www.ulib.iupui.edu >
