Exception: Unable to find clone for op Project 4-16 Projections

[Yonggang Qiao]

Hi,

anyone has seen this error before? normally our script runs fine, but
sometime recently it began to throw this exception. also usually it
will go away if I rerun it.

Caused by: java.lang.RuntimeException: Unable to find clone for op
Project 4-16 Projections: [9] Overloaded: false
        at 
org.apache.pig.impl.logicalLayer.LogicalPlan.clone(LogicalPlan.java:132)
        at 
org.apache.pig.impl.logicalLayer.LogicalPlanCloneHelper.<init>(LogicalPlanCloneHelper.java:66)
        at 
org.apache.pig.impl.logicalLayer.LogicalPlanCloner.getClonedPlan(LogicalPlanCloner.java:45)
        at 
org.apache.pig.impl.logicalLayer.parser.QueryParser.ForEachClause(QueryParser.java:3009)
        at 
org.apache.pig.impl.logicalLayer.parser.QueryParser.BaseExpr(QueryParser.java:1314)
        at 
org.apache.pig.impl.logicalLayer.parser.QueryParser.Expr(QueryParser.java:893)
        at 
org.apache.pig.impl.logicalLayer.parser.QueryParser.Parse(QueryParser.java:682)
        at 
org.apache.pig.impl.logicalLayer.LogicalPlanBuilder.parse(LogicalPlanBuilder.java:63)
        at org.apache.pig.PigServer$Graph.parseQuery(PigServer.java:1017)
        at org.apache.pig.PigServer$Graph.registerQuery(PigServer.java:967)
        at org.apache.pig.PigServer.registerQuery(PigServer.java:383)
        at org.apache.pig.PigServer.registerQuery(PigServer.java:399)
        at ...

Thanks,
Yonggang