- MySQL now includes DTrace support on Oracle Linux 6 or higher with UEK kernel.
- A new system variable
binlog_impossible_modecontrols what happens if the server cannot write to the binary log, for example, due to a file error.
- The mysqlhotcopy utility is now deprecated and will be removed in a future version of MySQL
5.6.20 has a slew of bug fixes, functionality changes, and notes.
So why should you be reading the changes on a regular basis? There isa goldmine of information in them. For instance, if you use
blobs, consider this:
Important Change: Redo log writes for large, externally stored BLOB fields could overwrite the most recent checkpoint. The 5.6.20 patch limits the size of redo log BLOB writes to 10% of the redo log file size. The 5.7.5 patch addresses the bug without imposing a limitation. For MySQL 5.5, the bug remains a known limitation.
As a result of the redo log BLOB write limit introduced for MySQL 5.6, innodb_log_file_size should be set to a value greater than 10 times the largest BLOB data size found in the rows of your tables plus the length of other variable length fields (VARCHAR, VARBINARY, and TEXT type fields). Failing to do so could result in “Row size too large” errors. No action is required if your innodb_log_file_size setting is already sufficiently large or your tables contain no BLOB data. (Bug #16963396, Bug #19030353, Bug #69477)
That is golden information for those of us who used a lot of
blobs and great info for configuring servers.