You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@lucene.apache.org by "Ankit Jain (Jira)" <ji...@apache.org> on 2022/02/18 21:39:00 UTC
[jira] [Created] (LUCENE-10428) getMinCompetitiveScore method in MaxScoreSumPropagator fails to converge leading to busy threads in infinite loop
Ankit Jain created LUCENE-10428:
-----------------------------------
Summary: getMinCompetitiveScore method in MaxScoreSumPropagator fails to converge leading to busy threads in infinite loop
Key: LUCENE-10428
URL: https://issues.apache.org/jira/browse/LUCENE-10428
Project: Lucene - Core
Issue Type: Bug
Components: core/query/scoring, core/search
Reporter: Ankit Jain
Customers complained about high CPU for Elasticsearch cluster in production. We noticed that few search requests were stuck for long time
```
% curl -s localhost:9200/_cat/tasks?v
indices:data/read/search[phase/query] AmMLzDQ4RrOJievRDeGFZw:569205 AmMLzDQ4RrOJievRDeGFZw:569204 direct 1645195007282 14:36:47 6.2h
indices:data/read/search[phase/query] emjWc5bUTG6lgnCGLulq-Q:502075 emjWc5bUTG6lgnCGLulq-Q:502074 direct 1645195037259 14:37:17 6.2h
indices:data/read/search[phase/query] emjWc5bUTG6lgnCGLulq-Q:583270 emjWc5bUTG6lgnCGLulq-Q:583269 direct 1645201316981 16:21:56 4.5h
```
Flame graphs indicated that CPU time is mostly going into *getMinCompetitiveScore method in MaxScoreSumPropagator*. After doing some live JVM debugging found that org.apache.lucene.search.MaxScoreSumPropagator.scoreSumUpperBound method had around 4 million invocations every second
Figured out the values of some parameters from live debugging:
```
minScoreSum = 3.5541441
minScore + sumOfOtherMaxScores (params[0] scoreSumUpperBound) = 3.554144322872162
returnObj scoreSumUpperBound = 3.5541444
Math.ulp(minScoreSum) = 2.3841858E-7
```
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@lucene.apache.org
For additional commands, e-mail: issues-help@lucene.apache.org