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https://issues.apache.org/jira/browse/HIVE-12312?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14995691#comment-14995691
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Carter Shanklin commented on HIVE-12312:
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Rebased. Saw that Sergey changed this recently to make it more efficient but
would still like to suggest debug level.
> Excessive logging in PPD code
> -----------------------------
>
> Key: HIVE-12312
> URL: https://issues.apache.org/jira/browse/HIVE-12312
> Project: Hive
> Issue Type: Bug
> Components: Hive
> Affects Versions: 1.2.1
> Reporter: Carter Shanklin
> Priority: Minor
> Attachments: HIVE-12312.1.patch, HIVE-12312.2.patch
>
>
> One of my very complex queries takes about 14 minutes to compile with PPD on.
> Profiling it I saw a lot of time spent in this stack which is called many
> many thousands of times.
> {code}
> java.lang.Throwable.getStackTraceElement(-2)
> java.lang.Throwable.getOurStackTrace(827)
> java.lang.Throwable.getStackTrace(816)
> sun.reflect.GeneratedMethodAccessor5.invoke(-1)
> sun.reflect.DelegatingMethodAccessorImpl.invoke(43)
> java.lang.reflect.Method.invoke(497)
> org.apache.log4j.spi.LocationInfo.<init>(139)
> org.apache.log4j.spi.LoggingEvent.getLocationInformation(253)
> org.apache.log4j.helpers.PatternParser$LocationPatternConverter.convert(500)
> org.apache.log4j.helpers.PatternConverter.format(65)
> org.apache.log4j.PatternLayout.format(506)
> org.apache.log4j.WriterAppender.subAppend(310)
> org.apache.log4j.DailyRollingFileAppender.subAppend(369)
> org.apache.log4j.WriterAppender.append(162)
> org.apache.log4j.AppenderSkeleton.doAppend(251)
> org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(66)
> org.apache.log4j.Category.callAppenders(206)
> org.apache.log4j.Category.forcedLog(391)
> org.apache.log4j.Category.log(856)
> org.apache.commons.logging.impl.Log4JLogger.info(176)
> org.apache.hadoop.hive.ql.ppd.OpProcFactory$DefaultPPD.logExpr(707)
> org.apache.hadoop.hive.ql.ppd.OpProcFactory$DefaultPPD.mergeWithChildrenPred(752)
> org.apache.hadoop.hive.ql.ppd.OpProcFactory$FilterPPD.process(437)
> {code}
> logExpr is set to log at INFO level, but I think DEBUG is more appropriate.
> When I set log level to debug I see > 20% speedup in compile time:
> Before:
> {code}
> real 14m47.972s
> user 15m25.609s
> sys 0m20.282s
> {code}
> After:
> {code}
> real 11m30.946s
> user 12m10.870s
> sys 0m7.320s
> {code}
> It looks like there's a lot of stuff in the PPD code that could be optimized,
> when I turn PPD off the query compiles in 2m 30s. But this seems like an easy
> and low risk win.
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