[jira] Commented: (PIG-226) Problem with streaming optimization

["Pi Song (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PIG-226?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12593715#action_12593715 ] 

Pi Song commented on PIG-226:
-----------------------------

Actually we have an interface called "ReversibleLoadStoreFunc" that enforces the load/store operations to be reversible.

Only  checking  "if (streamStorer instanceof LoadFunc)" is not enough because the load/store operations might not be symmetric.


The ReversibleLoadStoreFunc interface guarantees the property that:-
{noformat}
LoadFunc (StoreFunc(x)) = x
{noformat}

> Problem with streaming optimization
> -----------------------------------
>
>                 Key: PIG-226
>                 URL: https://issues.apache.org/jira/browse/PIG-226
>             Project: Pig
>          Issue Type: Bug
>            Reporter: Olga Natkovich
>            Assignee: Arun C Murthy
>         Attachments: PIG-226_0_20080501.patch
>
>
> Current optimization code assumes that every storeage function implements both LoadFunc and StoreFunc interfaces and causes an exception if it does not.
> 2008-05-01 13:31:23,662 [main] ERROR org.apache.pig.tools.grunt.Grunt - java.lang.RuntimeException: could not instantiate 'org.apache.pig.test.udf.storefunc.DumpLoader' with arguments '[]'
>         at org.apache.pig.impl.PigContext.instantiateFunc(PigContext.java:515)
>         at org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:521)
>         at org.apache.pig.impl.logicalLayer.optimizer.streaming.StoreOptimizer.visitStore(StoreOptimizer.java:103)
>         at org.apache.pig.impl.logicalLayer.LOStore.visit(LOStore.java:121)
>         at org.apache.pig.impl.logicalLayer.optimizer.streaming.StoreOptimizer.optimize(StoreOptimizer.java:145)
>         at org.apache.pig.PigServer.optimizeAndRunQuery(PigServer.java:411)
>         at org.apache.pig.PigServer.registerQuery(PigServer.java:297)
>         at org.apache.pig.tools.grunt.GruntParser.processPig(GruntParser.java:450)
>         at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:233)
>         at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:62)
>         at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:60)
>         at org.apache.pig.Main.main(Main.java:296)
> The code that needs to change is in impl/logicalLayer/optimizer/streaming/LoadOptimizer.java and impl/logicalLayer/optimizer/streaming/StoreOptimizer.java.
> The logic that needs to be added is if the load/store interface is not implemented then disable optimization.

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