[SOLR-15071] Bug on LTR when using solr 8.6.3 - index out of bounds DisiPriorityQueue.add(DisiPriorityQueue.java:102)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 8.6, 8.7
• Fix Version/s: 8.8, 9.0
• Component/s: contrib - LTR
• Labels: ltr
• Assignee: Christine Poerschke
• Reporter: Florin Babes
• Created: 06/Jan/21 15:46
• Updated: 12/May/22 00:26
• Resolved: 25/Jan/21 17:52

Description

Hello,
We are trying to update Solr from 8.3.1 to 8.6.3. On Solr 8.3.1 we are
using LTR in production using a MultipleAdditiveTrees model. On Solr 8.6.3
we receive an error when we try to compute some SolrFeatures. We didn't
find any pattern of the queries that fail.
Example:
We have the following query raw parameters:
q=lg cx 4k oled 120 hz -> just of many examples
term_dq=lg cx 4k oled 120 hz
rq={!ltr model=model reRankDocs=1000 store=feature_store
efi.term=${term_dq}}
defType=edismax,
mm=2<75%
The features are something like this:
{
"name":"similarity_query_fileld_1",
"class":"org.apache.solr.ltr.feature.SolrFeature",
"params":{"q":"

{!dismax qf=query_field_1 mm=1}

${term}"},
"store":"feature_store"
},
{
"name":"similarity_query_field_2",
"class":"org.apache.solr.ltr.feature.SolrFeature",
"params":{"q":"

{!dismax qf=query_field_2 mm=5}

${term}"},
"store":"feature_store"
}

We are testing ~6300 production queries and for about 1% of them we receive
that following error message:
"metadata":[
"error-class","org.apache.solr.common.SolrException",
"root-error-class","java.lang.ArrayIndexOutOfBoundsException"],
"msg":"java.lang.ArrayIndexOutOfBoundsException: Index 2 out of bounds
for length 2",

The stacktrace is :
org.apache.solr.common.SolrException:
java.lang.ArrayIndexOutOfBoundsException: Index 2 out of bounds for length 2
at org.apache.solr.search.ReRankCollector.topDocs(ReRankCollector.java:154)
at
org.apache.solr.search.SolrIndexSearcher.getDocListNC(SolrIndexSearcher.java:159
9)
at
org.apache.solr.search.SolrIndexSearcher.getDocListC(SolrIndexSearcher.java:1413
)
at
org.apache.solr.search.SolrIndexSearcher.search(SolrIndexSearcher.java:596)
at
org.apache.solr.handler.component.QueryComponent.doProcessUngroupedSearch(QueryC
omponent.java:1513)
at
org.apache.solr.handler.component.QueryComponent.process(QueryComponent.java:403
)
at
org.apache.solr.handler.component.SearchHandler.handleRequestBody(SearchHandler.
java:360)
at
org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java
:214)
at org.apache.solr.core.SolrCore.execute(SolrCore.java:2627)
at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:795)
at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:568)
at
org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:415)
at
org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:345)
at
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.jav
a:1596)
at
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545)
at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at
org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:590)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at
org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235
)
at
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:161
0)
at
org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233
)
at
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:130
0)
at
org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485)
at
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1580
)
at
org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
at
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1215
)
at
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at
org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerC
ollection.java:221)
at
org.eclipse.jetty.server.handler.InetAccessHandler.handle(InetAccessHandler.java
:177)
at
org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java
:146)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at
org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:322)
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.Server.handle(Server.java:500)
at
org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
at
org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273)
at
org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnectio
n.java:311)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
at
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.jav
a:336)
at
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.j
ava:313)
at
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.
java:171)
at
org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:12
9)
at
org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(Reserved
ThreadExecutor.java:375)
at
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
at
org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:
938)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.ArrayIndexOutOfBoundsException: Index 2 out of bounds
for length 2
at
org.apache.lucene.search.DisiPriorityQueue.add(DisiPriorityQueue.java:102)
at
org.apache.lucene.search.MinShouldMatchSumScorer.advanceTail(MinShouldMatchSumSc
orer.java:246)
at
org.apache.lucene.search.MinShouldMatchSumScorer.updateFreq(MinShouldMatchSumSco
rer.java:312)
at
org.apache.lucene.search.MinShouldMatchSumScorer.score(MinShouldMatchSumScorer.j
ava:320)
at
org.apache.solr.ltr.feature.SolrFeature$SolrFeatureWeight$SolrFeatureScorer.scor
e(SolrFeature.java:242)
at
org.apache.solr.ltr.LTRScoringQuery$ModelWeight$ModelScorer$SparseModelScorer.sc
ore(LTRScoringQuery.java:595)
at
org.apache.solr.ltr.LTRScoringQuery$ModelWeight$ModelScorer.score(LTRScoringQuer
y.java:540)
at org.apache.solr.ltr.LTRRescorer.scoreFeatures(LTRRescorer.java:183)
at org.apache.solr.ltr.LTRRescorer.rescore(LTRRescorer.java:122)
at org.apache.solr.search.ReRankCollector.topDocs(ReRankCollector.java:119)

 

Based on cpoerschke suggestions we detailed the following:

Reproducibility: We can reproduce the same queries on multiple runs, with the same error.

Data as a factor: Our setup is single-sharded, so we can't investigate further on this.

Feature vs. Model: We've also tried a dummy LinearModel with only two features and the problem still occurs.

Identification of the troublesome feature(s): We've narrowed our model to only two features and the problem always occurs (for some queries, not all) when we have a feature with a mm=1 and a feature with a mm>=3. The problem also occurs when we only do feature extraction and the problem seems to always occur on the feature with the bigger mm. The errors seem to be related to the size of the head DisiPriorityQueue created here: https://github.com/apache/lucene-solr/blob/branch_8_6/lucene/core/src/java/org/apache/lucene/search/MinShouldMatchSumScorer.java#L107 as the error changes as we change the mm for the second feature:

1 feature with mm=1 and one with mm=3 -> Index 4 out of bounds for length 4
1 feature with mm=1 and one with mm=5 -> Index 2 out of bounds for length 2

You can find below the dummy feature-store.

[
{
"store": "dummystore",
"name": "similarity_name_mm_1",
"class": "org.apache.solr.ltr.feature.SolrFeature",
"params":

{ "q": "\{!dismax qf=name mm=1}

${term}"
}
},
{
"store": "dummystore",
"name": "similarity_names_mm_3",
"class": "org.apache.solr.ltr.feature.SolrFeature",
"params":

{ "q": "\{!dismax qf=name mm=3}

${term}"
}
}
]

The problem starts occuring in Solr 8.6.0, as we tried multiple versions < 8.6 and >= 8.6 and the problem started on 8.6.0 and we tend to believe it's because of the following changes: https://issues.apache.org/jira/browse/SOLR-14364 as they're the only major changes related to LTR which were introduced in Solr 8.6.0.

 

Thanks.

 

Issue Links

• is broken by: SOLR-14364 LTR SolrFeature fq improvements, like PostFilters
• is broken by: SOLR-14378 factor out a (contrib/ltr) FilterFeatureScorer class
• relates to: SOLR-15958 review FilterFeatureScorer delegation logic w.r.t. Scorable
• links to: GitHub Pull Request #2196
• links to: GitHub Pull Request #2201