Maksim Zhuravkov created IGNITE-19917:
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Summary: Sql. Index scans/lookups should not result in physical
scans/looks when search conditions can not be satisfied.
Key: IGNITE-19917
URL: https://issues.apache.org/jira/browse/IGNITE-19917
Project: Ignite
Issue Type: Improvement
Components: sql
Reporter: Maksim Zhuravkov
Fix For: 3.0.0-beta2
The following query issues redundant requests to perform index lookups:
{code:java}
sql("SELECT * FROM smallint_val = 1000000000");
{code}
This query returns no result because `1000000000` lies out of valid value range
for `SMALLINT` type.
*Explanation*:
1. Type coercion rules correctly applies a cast to the left side operand,
translating the query into:
{code:java}
sql("SELECT * FROM smallint_val::INTEGER = 1000000000");
{code}
2. Since `smallint_val` column has type SMALLINT, we replace `1000000000` with
SMALLINT.MAX_VALUE.
3. Index scan/lookups are issued for ExactBounds
smallint_val=`SMALLINT.MAX_VALUE`, are then filtered by `predicate` specified
by `IgniteIndexScan`, thus producing no results.
It would be better if queries likes this would not issue redundant requests at
all. Such approach was implemented for IS NULL predicate (see
RangeConditionImpl defined in ExpressionFactoryImpl).
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