[jira] [Created] (PIG-3095) "which" is called many, many times for each Pig STREAM statement

["Nick White (JIRA)" <ji...@apache.org>]

Nick White created PIG-3095:
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             Summary: "which" is called many, many times for each Pig STREAM statement
                 Key: PIG-3095
                 URL: https://issues.apache.org/jira/browse/PIG-3095
             Project: Pig
          Issue Type: Bug
          Components: grunt, impl
    Affects Versions: 0.12
            Reporter: Nick White
            Assignee: Nick White
             Fix For: 0.12
         Attachments: PIG-3095.patch

STREAM statements are checked by the LogicalPlanBuilder as it comes across them - and these checks include running the system utility "which". However, due to the backtracking parsing mechanism "which" is called repeatedly with the same arguments (I noticed this while profiling a script with 4 STREAM statements - "which" was run over 230 times!). The attached patch just caches the return value of "which", reducing the overhead of running a system process to a Map lookup.

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