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04d027df13
It was disabled for performance reasons (IMPALA-1003) and this patch re-enables it since a lot of codegen improvements have happened since then. This patch switches the aggregation to use the CASE conditional instead of IF since the former has proper codegen support (IMPALA-7655). Tests: ===== - Updated the affected tests to include the null counts. - Added unit tests that verify IS [NOT] NULL predicates' cardinality estimation. Perf note: ========= I reran the compute stats child query with null counts included on the store_sales table from 1000 SF (1TB) tpcds dataset. The table had 22 non-partitioned columns (on which null counts were computed) and ~2.8B rows. This experiment showed around 7-8% perf drop compared to the same child query without null counts for these columns. Change-Id: Ic68f8b4c3756eb1980ce299a602a7d56db1e507a Reviewed-on: http://gerrit.cloudera.org:8080/11565 Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
15 lines
252 B
Plaintext
15 lines
252 B
Plaintext
====
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---- QUERY
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COMPUTE STATS `parquet`.impala_1055
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---- RESULTS
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'Updated 1 partition(s) and 1 column(s).'
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---- TYPES
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STRING
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====
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---- QUERY
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COMPUTE STATS `parquet`.`parquet`
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---- RESULTS
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'Updated 1 partition(s) and 1 column(s).'
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---- TYPES
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STRING
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==== |