Aman Sinha created IMPALA-10064:
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Summary: Support constant propagation for range predicates
Key: IMPALA-10064
URL: https://issues.apache.org/jira/browse/IMPALA-10064
Project: IMPALA
Issue Type: Improvement
Components: Frontend
Affects Versions: Impala 3.4.0
Reporter: Aman Sinha
Assignee: Aman Sinha
Consider the following table schema, view and 2 queries on the view:
{noformat}
create table tt1 (a1 int, b1 int, ts timestamp) partitioned by (mydate date);
create view tt1_view as (select a1, b1, ts from tt1 where mydate = cast(ts as
date));
// query 1: (Good) constant on ts gets propagated
explain select * from tt1_view where ts = '2019-07-01';
00:SCAN HDFS [db1.tt1]
partition predicates: mydate = DATE '2019-07-01'
HDFS partitions=1/3 files=2 size=48B
predicates: db1.tt1.ts = TIMESTAMP '2019-07-01 00:00:00'
row-size=24B cardinality=1
// query 2: (Not good) constant on ts does not get propagated
explain select * from tt1_view where ts > '2019-07-01';
00:SCAN HDFS [db1.tt1]
HDFS partitions=3/3 files=4 size=96B
predicates: db1.tt1.ts > TIMESTAMP '2019-07-01 00:00:00', mydate = CAST(ts
AS DATE)
row-size=28B cardinality=1
{noformat}
Note that in query 1, with the equality condition on 'ts' the constant value is
propagated to the 'mydate = CAST(ts as date)' predicate. This gets applied as
a partition predicate. Whereas, in query 2 which has a range predicate, the
constant is not propagated and no partition predicate is created for the scan.
We should support the second case also for constant propagation. The constant
predicates such as >, >=. <. <= and involving numeric or date literal should be
considered.
Note that a predicate can be a BETWEEN condition such as:
{noformat}
WHERE ts >= '2019-07-01' AND ts <= '2020--07-01'
{noformat}
In this case both need to be applied
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