Hi, Dušan! It's now reported as a bug, see https://jira.mariadb.org/browse/ODBC-313
Note, that you can add yourself to the watch list to get notified about this issue changes. Regards, Sergei VP of MariaDB Server Engineering and secur...@mariadb.org On Apr 30, Dušan Pavlica wrote: > 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 > _______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : maria-discuss@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp