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Re: Segmented Key Cache - About section


Henrik Ingo wrote:
> On Mon, May 17, 2010 at 9:14 PM, Igor Babaev <igor@xxxxxxxxxxxx> wrote:
>> 1. the author of the original patch
>> 2. our community members (not only PeterZ!)
>> 3. our developers
>> what term they prefer 'Segmented Key Cache' or 'Partitioned Key Cache'.
>> To be quite honest I also should mention that MichaelR from Oracle/MySQL
>> introduced in 5.5 a possibility for MySQL partitions in MyISAM to use
>> different key caches for different partitions. Before that all
>> partitions could use only default key caches. This feature is 100%
>> orthogonal to the discussed key cache partitioning.
> This was the only reason for the rename. (It is also the reason the
> rename was done after the implementation, and very fast, because we
> had to decide on a name before Monty's keynote.)

Look at Monty's keynote slide #12: it calls the feature clearly
"Partitioned Key Cache" (see
BTW, the slides were prepared NOT by me.


> So the main issue is to choose a name that will avoid confusion with
> the feature Mikael R has implemented. I think anything that achieves
> this can still be considered.

Mikael R did not call his new functionality for partition tables at all
because what he just lifted one of the limitations of his original
implementation: each MyISAM partition was a regular MyISAM table, but
not quite. In particular indexes of this table could not be assigned to
non-default key caches. So Mikael lifted this limitation. He did not
have to touch the key cache code at all.

> In any case, it is not the intent to change anything in the code,
> except I guess we need to syncronize the name of the feature with the
> user visible variable names.
> henrik

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