Did you have time to look at this? On Tue, Oct 13, 2020 at 2:43 PM David Smiley (Jira) <[email protected]> wrote:
> > [ > https://issues.apache.org/jira/browse/SOLR-14923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17213093#comment-17213093 > ] > > David Smiley commented on SOLR-14923: > ------------------------------------- > > I am responsible for this bug, along with [~moshebla], the contributor of > SOLR-12638. Perhaps the single most bit of code I've regretted committing > on behalf of another are the few lines of code you have found Thomas. I > expressed my reservations at the time: > > > https://issues.apache.org/jira/browse/SOLR-12638?focusedCommentId=16872898&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16872898 > > bq. What gnaws at me is that this "UpdateLog.openRealtimeSearcher" is > being called optimistically on a new doc because maaaayyyybeee some future > atomic update will need to see it. And not just any type of atomic update; > one that is directly to a nested child doc (something I consider highly > experimental). It's as if we're optimizing for making that future atomic > update faster by doing work in advance that will, I think, very rarely > actually be used. It's a tragedy, if I'm understanding this right. > > There's a bit of conversation before in the issue about it as well. It's > difficult for me to say at the moment what the fix is because that's fairly > complex low-level Solr code that I think few people understand well. > Nonetheless I'll look into it further this week. > > > > Indexing performance is unacceptable when child documents are involved > > ---------------------------------------------------------------------- > > > > Key: SOLR-14923 > > URL: https://issues.apache.org/jira/browse/SOLR-14923 > > Project: Solr > > Issue Type: Bug > > Security Level: Public(Default Security Level. Issues are Public) > > Components: update, UpdateRequestProcessors > > Affects Versions: master (9.0), 8.3, 8.4, 8.5, 8.6 > > Reporter: Thomas Wöckinger > > Priority: Critical > > Labels: performance > > > > Parallel indexing does not make sense at moment when child documents are > used. > > The org.apache.solr.update.processor.DistributedUpdateProcessor checks > at the end of the method doVersionAdd if Ulog caches should be refreshed. > > This check will return true if any child document is included in the > AddUpdateCommand. > > If so ulog.openRealtimeSearcher(); is called, this call is very > expensive, and executed in a synchronized block of the UpdateLog instance, > therefore all other operations on the UpdateLog are blocked too. > > Because every important UpdateLog method (add, delete, ...) is done > using a synchronized block almost each operation is blocked. > > This reduces multi threaded index update to a single thread behavior. > > The described behavior is not depending on any option of the > UpdateRequest, so it does not make any difference if 'waitFlush', > 'waitSearcher' or 'softCommit' is true or false. > > The described behavior makes the usage of ChildDocuments useless, > because the performance is unacceptable. > > > > > > > > -- > This message was sent by Atlassian Jira > (v8.3.4#803005) > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
