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Tim Armstrong updated IMPALA-10349: ----------------------------------- Component/s: Frontend > Revisit constant folding on non-ASCII strings > --------------------------------------------- > > Key: IMPALA-10349 > URL: https://issues.apache.org/jira/browse/IMPALA-10349 > Project: IMPALA > Issue Type: Improvement > Components: Frontend > Reporter: Quanlong Huang > Priority: Major > > Constant folding may produce non-ASCII strings. In such cases, we currently > abandon folding the constant. See commit message of IMPALA-1788 or codes > here: > [https://github.com/apache/impala/blob/9672d945963e1ca3c8699340f92d7d6ce1d91c9f/fe/src/main/java/org/apache/impala/analysis/LiteralExpr.java#L274-L282] > I think we should allow folding non-ASCII strings if they are legal UTF-8 > strings. > Example of constant folding work: > {code:java} > Query: explain select * from functional.alltypes where string_col = > substr('123', 1, 1) > +-------------------------------------------------------------+ > | Explain String | > +-------------------------------------------------------------+ > | Max Per-Host Resource Reservation: Memory=32.00KB Threads=3 | > | Per-Host Resource Estimates: Memory=160MB | > | Codegen disabled by planner | > | | > | PLAN-ROOT SINK | > | | | > | 01:EXCHANGE [UNPARTITIONED] | > | | | > | 00:SCAN HDFS [functional.alltypes] | > | HDFS partitions=24/24 files=24 size=478.45KB | > | predicates: string_col = '1' | > | row-size=89B cardinality=730 | > +-------------------------------------------------------------+ > {code} > Example of constant folding doesn't work: > {code:java} > Query: explain select * from functional.alltypes where string_col = > substr('引擎', 1, 3) > +-------------------------------------------------------------+ > | Explain String | > +-------------------------------------------------------------+ > | Max Per-Host Resource Reservation: Memory=32.00KB Threads=3 | > | Per-Host Resource Estimates: Memory=160MB | > | Codegen disabled by planner | > | | > | PLAN-ROOT SINK | > | | | > | 01:EXCHANGE [UNPARTITIONED] | > | | | > | 00:SCAN HDFS [functional.alltypes] | > | HDFS partitions=24/24 files=24 size=478.45KB | > | predicates: string_col = substr('引擎', 1, 3) | > | row-size=89B cardinality=730 | > +-------------------------------------------------------------+ > {code} -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org