maria-discuss team mailing list archive

[Pavel Ivanov <pivanof@xxxxxxxxxx>]

> For example, in MariaDB one can use InnoDB
> for system tables too. Always could, even in 5.5, it's not a new
> feature. There is no code that limits system tables to a specific
> storage engine.

This is not true even in MariaDB 10.2:
https://github.com/MariaDB/server/blob/10.2/storage/innobase/row/row0mysql.cc#L5398.
And that's only the explicit restriction. Even when you remove that
you still need a lot of other code changes to make MariaDB work with
system tables using InnoDB. There are many places assuming that system
tables are not transactional.


On Thu, Oct 13, 2016 at 4:00 PM, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> Hi, Ricky!
>
> On Oct 13, Ricky B wrote:
>> Thanks for the write up Colin.
>>
>> I had known about TokuDB potentially being dropped due to lack of
>> developers and support. Understandable, but a real shame. At least rocksdb
>> has a backup tool and some fun snapshot features.
>
> There is development and support for TokuDB. The main reason for
> dropping it could be RocksDB based engine covering all TokuDB use cases,
> but better. I mean, *if* RocksDB will be able to do that, then TokuDB
> won't be needed (it's *if*, not a certainty).
>
>> What I really want to know is, what's the future of transactional DDL
>> in MariaDB (MDEV-4259) with the impending changes in MySQL 8? How much
>> of that is going to be merged with MariaDB?
>
> Current understanding is - not much of it. We seem to be going different
> path. MySQL is moving everything into InnoDB - one engine to rule them
> all. System tables are in InnoDB, data dictionary is is InnoDB,
> temporary tables - too. And so on. New storage engine API extensions
> work only for InnoDB. The manual has a chapter on InnoDB and a chapter
> on "alternative storage engines".
>
> MariaDB - currently - tries to treat all engines equally. More or less.
> New storage engine API extensions work for all capable engines - almost
> always for more than one. New features are added in the engine
> independent way. And so on. For example, in MariaDB one can use InnoDB
> for system tables too. Always could, even in 5.5, it's not a new
> feature. There is no code that limits system tables to a specific
> storage engine. FRM files in MariaDB are optional since 10.0. But it
> depends on the engine, and InnoDB relies on FRM files in MariaDB. May be
> we will change it in 10.3, then InnoDB tables won't use FRM files
> anymore and DDLs will be atomic and may be, in some later version, even
> transactional.
>
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx
>
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