Fix broken DatabaseMetaData.getColumns() on older server versions #182
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On older versions of MariaDB and MySQL, DatabaseMetaData.getColumns() will fail with the error "Unknown column 'DATETIME_PRECISION' in 'field list'". This is due to the DATETIME_PRECISION column not being present in the INFORMATION_SCHEMA.COLUMNS table. This column was introduced as part of the introduction of microsecond precision in TIME/DATETIME/TIMESTAMP types, in MariaDB 5.3.0 (I believe) and MySQL 5.6.4. The proposed fix adjusts the metadata query for the relevant older server versions. The behavior is as if the DATETIME_PRECISION field had a value of 0, which is consistent with the fact that these older database versions did not support any fractional seconds digits. Similar conditional logic already exist in the MySQL project's JDBC driver.
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Thanks for the PR. |
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Thank you for the quick review and merge! (Handling some older unsupported server versions is useful for tools that are supposed to be able to connect to arbitrary MySQL/MariaDB instances, and lets us use the MariaDB driver for both.) |
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On older versions of MariaDB and MySQL, DatabaseMetaData.getColumns() will fail with the error
Unknown column 'DATETIME_PRECISION' in 'field list'. This is due to theDATETIME_PRECISIONcolumn not being present in theINFORMATION_SCHEMA.COLUMNStable. This column was introduced as part of the introduction of microsecond precision in TIME/DATETIME/TIMESTAMP types, in MariaDB 5.3.0 (I believe) and MySQL 5.6.4.The proposed fix adjusts the metadata query for the relevant older server versions. The fixed behavior in these cases is as if the DATETIME_PRECISION field had a value of 0, which is consistent with the fact that these older database versions did not support any fractional seconds digits.
Similar conditional logic already exist in the MySQL project's JDBC driver.
(This bug was reported by a user of Ultorg, a graphical database client. To test the modified MariaDB JDBC driver, I ran Ultorg's integration test suite with it while connecting to MariaDB 10.6.11, MySQL 5.5.62, and MySQL 8.0.26.)