[MCOL-3698] Dynamic columns can be stored in ColumnStore table, but cannot be extracted Created: 2019-12-26  Updated: 2023-07-02  Resolved: 2023-07-02

Status: Closed
Project: MariaDB ColumnStore
Component/s: N/A
Affects Version/s: 1.4.2
Fix Version/s: Icebox

Type: New Feature Priority: Minor
Reporter: Elena Stepanova Assignee: Todd Stoffel (Inactive)
Resolution: Won't Do Votes: 0
Labels: None

Epic Link: ColumnStore Compatibility Improvements

 Description   

drop table if exists t2;
create table t2 (b blob) engine=Columnstore;
insert into t2 values (column_create('foo','bar'));
select column_json(b) from t2;

MariaDB f93bfb9288d020b190f5c73a31223fff6439687d

MariaDB [db]> insert into t2 values (column_create('foo','bar'));
Query OK, 1 row affected (0.148 sec)
 
MariaDB [db]> select column_json(b) from t2;
ERROR 1178 (42000): The storage engine for the table doesn't support IDB-1001: Function 'column_json' can only be used in the outermost select or order by clause and cannot be used in conjunction with an aggregate function.

It's not very surprising that functionality is not supported, but the error is strange, and also probably INSERT should be rejected.



 Comments   
Comment by Andrew Hutchings (Inactive) [ 2019-12-26 ]

INSERT will work because MariaDB server is executing the function. SELECT will fail because the JSON functions have not been implemented in ColumnStore. There is a workaround with a large performance penalty (disable select handler). Almost certain we have a duplicate ticket for JSON functions somewhere.

Comment by Todd Stoffel (Inactive) [ 2023-07-02 ]

The "create date" on this ticket is pre-convergence with MariaDB server. If the issue still exists in a modern version of the engine/plugin please submit a new ticket.

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