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Michael McCandless commented on LUCENE-7868: -------------------------------------------- Ugh, sorry, I though I had done that, but I must have forgot to click the "Publish Changes" button. Try now? I also realize I failed to click Publish Changes on my replies to your first review, sheesh!! So I clicked that now and I guess you now got an email with my comments from the *first* iteration! > Use multiple threads to apply deletes and DV updates > ---------------------------------------------------- > > Key: LUCENE-7868 > URL: https://issues.apache.org/jira/browse/LUCENE-7868 > Project: Lucene - Core > Issue Type: Improvement > Reporter: Michael McCandless > Assignee: Michael McCandless > Fix For: master (7.0) > > Attachments: cpu-after.png, cpu-before.png, LUCENE-7868.patch, > LUCENE-7868.patch, LUCENE-7868.patch, LUCENE-7868.patch, LUCENE-7868.patch, > LUCENE-7868.patch > > > Today, when users delete documents or apply doc values updates, IndexWriter > buffers them up into frozen packets and then eventually uses a single thread > (BufferedUpdatesStream.applyDeletesAndUpdates) to resolve delete/update terms > to docids. This thread also holds IW's monitor lock, so it also blocks > refresh, merges starting/finishing, commits, etc. > We have heavily optimized this part of Lucene over time, e.g. LUCENE-6161, > LUCENE-2897, LUCENE-2680, LUCENE-3342, but still, it's a single thread so it > can't use multiple CPU cores commonly available now. > This doesn't affect append-only usage, but for update-heavy users (me!) this > can be a big bottleneck, and causes long stop-the-world hangs during indexing. > I have an initial exploratory patch to make these lookups concurrent, without > holding IW's lock, so that when a new packet of deletes is pushed, which > happens when we flush a new segment, we immediately use that same indexing > thread to and resolve the deletions. > This is analogous to when we made segment flushing concurrent (LUCENE-3023), > just for deletes and DV updates as well. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org