maria-discuss team mailing list archive

[Dušan Pavlica <pavlica@xxxxxxxxxxx>]

Hi,

I'm new with MariaDB. We try to switch from MySQL 5.0.96 to MariaDB 
10.5.9. Move data to MariaDB was easy but now we have problems with 
speed of ODBC connector. I tried MariaDB ODBC connector 3.1.12 with 
default settings without SSL and our applications (mostly written in 
Embarcadero RAD Studio) showed very poor performance. When I tried MySQL 
ODBC connector 8.0.24 everything ran smoothly. Queries through MariaDB's 
connector was 3-5 times slower. In general query log I found that 
MariaDB's connector generates a lot of queries to 
information_scheme.columns table and all over again it reads variable 
TX_ISOLATION.

Short extract - MariaDB connector:

             3 Query    SELECT VARIABLE_VALUE FROM 
INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME='TX_ISOLATION'
             3 Prepare    select * from stanice
             3 Execute    select * from stanice
             3 Prepare    SELECT TABLE_SCHEMA AS TABLE_CAT, NULL AS 
TABLE_SCHEM, TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION KEY_SEQ, 
'PRIMARY' PK_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_KEY = 
'pri' AND TABLE_SCHEMA LIKE 'unicentrum' AND TABLE_NAME LIKE 'stanice'  
ORDER BY TABLE_SCHEMA, TABLE_NAME, ORDINAL_POSITION
             3 Execute    SELECT TABLE_SCHEMA AS TABLE_CAT, NULL AS 
TABLE_SCHEM, TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION KEY_SEQ, 
'PRIMARY' PK_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_KEY = 
'pri' AND TABLE_SCHEMA LIKE 'unicentrum' AND TABLE_NAME LIKE 'stanice'  
ORDER BY TABLE_SCHEMA, TABLE_NAME, ORDINAL_POSITION
             3 Close stmt
             3 Reset stmt
             3 Query    SELECT VARIABLE_VALUE FROM 
INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME='TX_ISOLATION'
             3 Prepare    SELECT * FROM stanice WHERE Sit_ID = ?
ORDER BY Sit_ID, Podsit_ID, ID
             3 Execute    SELECT * FROM stanice WHERE Sit_ID = 1
ORDER BY Sit_ID, Podsit_ID, ID
             3 Prepare    SELECT TABLE_SCHEMA AS TABLE_CAT, NULL AS 
TABLE_SCHEM, TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION KEY_SEQ, 
'PRIMARY' PK_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_KEY = 
'pri' AND TABLE_SCHEMA LIKE 'unicentrum' AND TABLE_NAME LIKE 'stanice'  
ORDER BY TABLE_SCHEMA, TABLE_NAME, ORDINAL_POSITION
             3 Execute    SELECT TABLE_SCHEMA AS TABLE_CAT, NULL AS 
TABLE_SCHEM, TABLE_NAME, COLUMN_NAME, ORDINAL_POSITION KEY_SEQ, 
'PRIMARY' PK_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_KEY = 
'pri' AND TABLE_SCHEMA LIKE 'unicentrum' AND TABLE_NAME LIKE 'stanice'  
ORDER BY TABLE_SCHEMA, TABLE_NAME, ORDINAL_POSITION
             3 Close stmt
             3 Reset stmt

MySQL connector:

             3 Query    SELECT @@tx_isolation
             ...
             3 Query    select * from stanice
             3 Prepare    SELECT * FROM stanice WHERE Sit_ID = ?
ORDER BY Sit_ID, Podsit_ID, ID
             3 Execute    SELECT * FROM stanice WHERE Sit_ID = '1'
ORDER BY Sit_ID, Podsit_ID, ID
             3 Close stmt

I think those "unnecessary" queries are making difference in performance 
of those connectors. Does anybody have any ideas what could I do to 
speed up MariaDB's connector? We prefer not using MySQL connectors anymore.

Thanks in advance

Dušan Pavlica