[Enhancement] union all opt

[cambyzju]

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Description

Problem:
select * from t where k=1 union all select * from t where k=3;

should convert to:

select * from t where k=1 or k=3;

to reduce scanners

Reproduce Steps:
1、create table：

CREATE TABLE `t` (
  `k` int NULL,
  `v` int NULL
) ENGINE=OLAP
DUPLICATE KEY(`k`)
DISTRIBUTED BY HASH(`k`) BUCKETS AUTO
PROPERTIES (
"replication_allocation" = "tag.location.default: 1");

2、add data：
insert into t values(1,2),(3,4);

3、explain union all SQL

> explain shape plan select * from t where k=1 union all select * from t where k=3;
+--------------------------------------------------------+
| Explain String(Nereids Planner)                        |
+--------------------------------------------------------+
| PhysicalResultSink                                     |
| --PhysicalDistribute[DistributionSpecGather]           |
| ----PhysicalUnion                                      |
| ------PhysicalDistribute[DistributionSpecExecutionAny] |
| --------filter((t.k = 1))                              |
| ----------PhysicalOlapScan[t]                          |
| ------PhysicalDistribute[DistributionSpecExecutionAny] |
| --------filter((t.k = 3))                              |
| ----------PhysicalOlapScan[t]                          |
+--------------------------------------------------------+

4、explain equal SQL：

> explain shape plan select * from t where k=1 or k=3;
+----------------------------------------------+
| Explain String(Nereids Planner)              |
+----------------------------------------------+
| PhysicalResultSink                           |
| --PhysicalDistribute[DistributionSpecGather] |
| ----filter(k IN (1, 3))                      |
| ------PhysicalOlapScan[t]                    |
+----------------------------------------------+

Solution

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

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