Timour Katchaounov added a comment - 2012-08-15 15:58 = The feature The feature generalizes all the possible ways to set the default value, and to update automatically the value of both TIMESTAMP and DATETIME fields. It makes the clauses DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP applicable to both TIMESTAMP and DATETIME fields, and allows to specify the default value as well as the update value on any TIMESTAMP and DATETIME field in the same table. For full usability, the feature should be paired together with the system variable sysvar_explicit_defaults_for_timestamp from MySQL 5.6.6 that deprecates the implicit default values of TIMESTAMP fileds, and results in NULL behavior typical for other data types. Therefore from feature perspective, this seems to useful. Backporting this feature will also allow MariaDB to be compatible in this respect with future MySQL versions. = The code The part of the diff related to code changes is 6096 lines, however only 4697 lines are related to changes in the server, the rest is unit testing code. Unfortunately until looking at this code I was totally unfamiliar with this area, therefore my analysis is not very deep. From what I could tell by reading the patch: it seems to be self-contained. I tracked several new/changed data structures, and found them to be defined in the same patch. The patch performs some refactoring, for instance it transforms struct st_copy_info into a class COPY_INFO. There also are some minor refactoring/formatting changes. it doesn't change the FRM format (at least there are no changed or new enum values in "utype"). it doesn't modify the parser (the YACC file) Backporting the patch mechanically should be possible in 2-3 days, then we need to allocate time to backport the test cases, and to test the final result. With my current background I am not able to tell if there is a simpler and/or more ellegant way to implement this functionality.