I’ve finally found time to put together a couple of wiki pages describing what work we’re doing for subquery optimizations in MySQL 6.0:
- The Subquery_Works page has an overview of what we’ve done so far, we’re doing now and our future plans.
- The 6.0 Subquery Optimization Cheatsheet has a short, easy-to-read description of what has been released in MySQL 6.0.3. That should be enough if you just want to get the new version and see if your subquery is/can be faster now or not. If you want to know more details, the nearest occasion is my MySQL University session on February, 28.
- I’ve done a quick preliminary assessment of the impact of new optimizations. The raw results and first conclusions are here on the 6.0 Subquery Optimization Benchmarks page. We will be doing more analysis and I intend to post more observations based on the already collected data, stay tuned.
That’s everything I have on subqueries so far, but as I’ve already mentioned more is on the way.
Sergei Petrunia's blog 
Seems to be lots of speed improvements.
Probably combining it with “Maria”, would get a very nice performance, as compared with 5.x.
LikeLike
Well, at the moment subquery optimizations are not expected to have any interplay with Maria’s speedups that I am aware of.
The good part is that they aren’t mutually exclusive either, so one can hope to get both Maria’s and subquery optimization improvements.
IIRC the first release(s) of Maria are focused on recovery though.
LikeLike