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  1. IMPALA
  2. IMPALA-4192

Pull all expressions in a fragment into RuntimeState

    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: Impala 2.8.0
    • Fix Version/s: None
    • Component/s: Backend
    • Labels:

      Description

      Currently, Exprs in a fragment are scattered through the TPlanNode in a fragment. Expr is supposed to be shared by all threads but they are always accessed through thread-private state ExprContext. With multi-threading, an Expr in a fragment and its generated IR function should be shared among all instances of it.

      As part of IMPALA-4080, all Expr in a fragment will be moved to query-wide state instead of having multiple copies of them in the exec nodes of each instances. In addition, moving Expr to query-wide state prevents the mistakes of baking in thread private states (e.g. ExprContext pointers) into the generated IR code for an Expr.

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              • Assignee:
                kwho Michael Ho
                Reporter:
                kwho Michael Ho
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                • Created:
                  Updated: