Many InnoDB scalability problems seem fixed in InnoDB-plugin-1.0.3 and I expect InnoDB-plugin will run fine on 16-24 cores boxes for many workloads. And now it is time to look on systems with 32GB+ of RAM which are not rare nowadays. Working with real customer systems I have wish-list of features I would like to see soon:
- Fast recovery. Both recovery after crash and recovery from backup can take unacceptable long time, especially if you crashed with full 32GB buffer_pool. There is reported bug http://bugs.mysql.com/bug.php?id=29847, with ETA MySQL-6.0
- Preload table / index into buffer_pool. You can use custom queries by primary / secondary key to “warm up” part of table, but this solution is ugly and may be slow due to random logical I/O. Implementing preload of full .ibd file with sequential read would be much better solution. This is actually more important feature than it may appear at first look – for example if you put load on slave which is not warmed up properly – slave may never catch up slave, but with small load warm up may take hours to complete, so basically it adds several hours for operations team to complete task which requires restart of slave
- Copy single .ibd table from one server to different or (basically the same) restore single table from backup, possibly on different server (different slave). It’s all about time – copying whole 500GB backup while you need to restore only single 20GB table is very non-productive
- Open InnoDB tables in parallel. Currently opening table is serialized, and it is especially bad at start time, when InnoDB takes probes during opening table, as it is slow operation. See also http://www.percona.com/blog/2006/11/21/opening-tables-scalability/. Partially it can be fixed by recent patches by enabling / disabling probes and changing count of probes, but still the solution is far from perfect
As you see the list list is not about performance but mostly about operations tasks, but with current amount of data and memory on servers they become critical. I do not know what is InnoDB plans about it and would like to hear if this is will be implemented anytime soon or never. Anyway I was asked what are our current plans about XtraDB with recent InnoDB-pluging release, as performance improvements in plugin may make XtraDB out of game – so I consider list above as roadmap for XtraDB and hope some or all features are implemented this year.
Do you have any other features you miss in current InnoDB ?