Another new year by Jewish calendar. What do I wish for the following year?
- World peace
- Good health to all
- Decent, operations friendly built in online table refactoring
The existing online ALTER TABLE solution is still not there. It does not take into consideration the load on the server. In replication stream it’s serialized just as any other statement. It’s not easy to stop/revert in case of problem.
The existing online-schema-change scripts are still based on my 6-year old original solution, I’m proud to say, but the technology used, i.e. triggers, hasn’t really evolved since then. We are still fighting deadlocks induced by the use of triggers and/or concurrent copying of data. There are still limitations on use of foreign keys.
None of my wishes in previous years [2010], [2011], [2012], [2013], [2014] came true (and mostly gone worse). I’m still willing to settle for two out of three.
Wait! Another year passed by already? 😮
And still no multi-core processing of queries…
It should be possible to implement the online-schema-change within the engine itself but it could create all sorts of problems with locking that are now nicely resolved by isolating the problem outside the InnoDB engine.
Who knows what has happened wihtin a year from now. Maybe Jeremy’s table flip is the new online-schema-change method of choice?