[Gllug] mysql source install upgrade

[Aaron Trevena]

On 30/03/2008, Karanbir Singh <mail-lists at karan.org> wrote:
> Aaron Trevena wrote:
>  > Yes, but being forewarned of issues makes the difference between doing
>  > the test and live upgrade tomorrow as well as myisam to innodb
>  > conversion or just the latter.
>
>
> Apart from the fact that you loose fulltext capability in innodb, I dont
>  think there is any major issue in converting db engines. also, I guess
>  you have reasons to move from one to the other, so would have already
>  done a feature comparison and decided that innodb did give you what you
>  need.

It's a bit of rock and hard place - myisam isn't coping with the level
of writes, but when they tried moving to innodb some queries were
apparently 10 times slower - unfortunately I haven't been able to
repeat that with my benchmarks, nobody can remember which query it was
and can't tell me if that's the real problem or if it was just an
effect of the old concurrency / thread thrashing bug which was fixed
several versions ago.

>  Also, are you doing a dump + reload with the changed create table
>  definitions or doing the conversion in-place on the live db ?

The old Switcheroo :)

create new table with different name, "select into" new table, rename
old and new tables. This is much quicker than dump/restore and
reversable unlike like in-place.

I'm installing the latest mysql from source side by side (/usr/local
vs /usr) so that we can avoid the old concurrency bugs and/or fall
back to the previous working (if overworked) set up if problems
encountered.

The tricky bit is sorting out the slaves - my plan is to concurrently
switch tables on master and slave (reversable and quick), then reset
replication to start from the same point on the master.

A.

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