Joe McDonnell created IMPALA-12800:
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Summary: Queries with many nested inline views see performance
issues with ExprSubstitutionMap
Key: IMPALA-12800
URL: https://issues.apache.org/jira/browse/IMPALA-12800
Project: IMPALA
Issue Type: Improvement
Components: Frontend
Affects Versions: Impala 4.3.0
Reporter: Joe McDonnell
A user running a query with many layers of inline views saw a large amount of
time spent in analysis.
{noformat}
- Authorization finished (ranger): 7s518ms (13.134ms)
- Value transfer graph computed: 7s760ms (241.953ms)
- Single node plan created: 2m47s (2m39s)
- Distributed plan created: 2m47s (7.430ms)
- Lineage info computed: 2m47s (39.017ms)
- Planning finished: 2m47s (672.518ms){noformat}
In reproducing it locally, we found that most of the stacks end up in
ExprSubstitutionMap.
Here are the main stacks seen while running jstack every 3 seconds during a 75
second execution:
Location 1: (ExprSubstitutionMap::compose -> contains -> indexOf -> Expr
equals) (4 samples)
{noformat}
java.lang.Thread.State: RUNNABLE
at org.apache.impala.analysis.Expr.equals(Expr.java:1008)
at java.util.ArrayList.indexOf(ArrayList.java:323)
at java.util.ArrayList.contains(ArrayList.java:306)
at
org.apache.impala.analysis.ExprSubstitutionMap.compose(ExprSubstitutionMap.java:120){noformat}
Location 2: (ExprSubstitutionMap::compose -> verify -> Expr equals) (9 samples)
{noformat}
java.lang.Thread.State: RUNNABLE
at org.apache.impala.analysis.Expr.equals(Expr.java:1008)
at
org.apache.impala.analysis.ExprSubstitutionMap.verify(ExprSubstitutionMap.java:173)
at
org.apache.impala.analysis.ExprSubstitutionMap.compose(ExprSubstitutionMap.java:126){noformat}
Location 3: (ExprSubstitutionMap::combine -> verify -> Expr equals) (5 samples)
{noformat}
java.lang.Thread.State: RUNNABLE
at org.apache.impala.analysis.Expr.equals(Expr.java:1008)
at
org.apache.impala.analysis.ExprSubstitutionMap.verify(ExprSubstitutionMap.java:173)
at
org.apache.impala.analysis.ExprSubstitutionMap.combine(ExprSubstitutionMap.java:143){noformat}
Location 4: (TupleIsNullPredicate.wrapExprs -> Analyzer.isTrueWithNullSlots
-> FeSupport.EvalPredicate -> Thrift serialization) (4 samples)
{noformat}
java.lang.Thread.State: RUNNABLE
at java.lang.StringCoding.encode(StringCoding.java:364)
at java.lang.String.getBytes(String.java:941)
at
org.apache.thrift.protocol.TBinaryProtocol.writeString(TBinaryProtocol.java:227)
at
org.apache.impala.thrift.TClientRequest$TClientRequestStandardScheme.write(TClientRequest.java:532)
at
org.apache.impala.thrift.TClientRequest$TClientRequestStandardScheme.write(TClientRequest.java:467)
at org.apache.impala.thrift.TClientRequest.write(TClientRequest.java:394)
at
org.apache.impala.thrift.TQueryCtx$TQueryCtxStandardScheme.write(TQueryCtx.java:3034)
at
org.apache.impala.thrift.TQueryCtx$TQueryCtxStandardScheme.write(TQueryCtx.java:2709)
at org.apache.impala.thrift.TQueryCtx.write(TQueryCtx.java:2400)
at org.apache.thrift.TSerializer.serialize(TSerializer.java:84)
at
org.apache.impala.service.FeSupport.EvalExprWithoutRowBounded(FeSupport.java:206)
at
org.apache.impala.service.FeSupport.EvalExprWithoutRow(FeSupport.java:194)
at org.apache.impala.service.FeSupport.EvalPredicate(FeSupport.java:275)
at
org.apache.impala.analysis.Analyzer.isTrueWithNullSlots(Analyzer.java:2888)
at
org.apache.impala.analysis.TupleIsNullPredicate.requiresNullWrapping(TupleIsNullPredicate.java:181)
at
org.apache.impala.analysis.TupleIsNullPredicate.wrapExpr(TupleIsNullPredicate.java:147)
at
org.apache.impala.analysis.TupleIsNullPredicate.wrapExprs(TupleIsNullPredicate.java:136){noformat}
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