Details
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New Feature
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Status: Closed (View Workflow)
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Major
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Resolution: Duplicate
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1.0.0
Description
Extent exlimination works regarding
https://mariadb.com/kb/en/library/columnstore-storage-architecture/
"filter value is compared to the minimum and maximum values stored in each extent for the column: If the filter value is outside of a extent's min-max value range, the extent is eliminated."
This is not the case for the datatypes char(>8) and double (+real)
To Reproduce:
Create Table
create database `etest`; |
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USE `etest` ; |
CREATE TABLE `etest` |
(
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`e01` int , |
`e02` char(8) , |
`e03` char(9) , |
`e04` decimal , |
`e05` double , |
`e06` real |
) engine=columnstore;
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}
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Activate extends elimination with insert value and select col from table for every column.
insert into `etest` (`e01`,`e02`,`e03`,`e04`,`e05`,`e06`) VALUES (1,'12345678','123456789',1.1,1.1,1.1); |
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select `e01` from `etest` ; |
select `e02` from `etest` ; |
select `e03` from `etest` ; |
select `e04` from `etest` ; |
select `e05` from `etest` ; |
select `e06` from `etest` ; |
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MariaDB [etest]> select ce.object_id,object_type,min_value,max_value,state,status,cc.data_type,cc.column_length from `information_schema`.`COLUMNSTORE_EXTENTS` ce left join `information_schema`.`COLUMNSTORE_COLUMNS` cc on ce.object_id = cc.object_id where cc.table_schema = 'etest' and cc.table_name = 'etest'; |
+-----------+-------------+---------------------+---------------------+---------+-----------+-----------+---------------+ |
| object_id | object_type | min_value | max_value | state | status | data_type | column_length |
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+-----------+-------------+---------------------+---------------------+---------+-----------+-----------+---------------+ |
| 3023 | Column | 1 | 1 | Valid | Available | int | 4 | |
| 3024 | Column | 4050765991979987456 | 4050765991979987456 | Valid | Available | char | 8 | |
| 3025 | Column | NULL | NULL | Invalid | Available | char | 9 | |
| 3026 | Column | NULL | NULL | Invalid | Available | decimal | 8 | |
| 3027 | Column | NULL | NULL | Invalid | Available | double | 8 | |
| 3028 | Column | NULL | NULL | Invalid | Available | double | 8 | |
+-----------+-------------+---------------------+---------------------+---------+-----------+-----------+---------------+ |
6 rows in set (0.06 sec) |
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CHAR(8) and int will be recognized feature.
CHAR(9) also double(real) even if column length is only 8.
It would be nice and a performance bonus, if these datatypes will be included into the extents elimination feature.
Richard