Subject Re: [Firebird-Architect] Question about limits in fb 2.5 or 3.0
Author Dmitry Yemanov
Jim Starkey wrote:
>
>> Yep, it's already in the tracker and seems quite easy to offer. However,
>> I foresee some problems for compound indices.
>
> What problem? They're implemented in Falcon and it was straightforward.

It's not a technical problem, more like a support one :-)

Obviously, you cannot truncate the every segment of the compound index
before constructing the key, it can be truncated as a whole only. With
the first segment being long enough, it could mean that other segments
are not indexed at all (with a performance impact), regardless of the
user intentions specified in DDL. Not a big problem for sure, just a
possible confusion.

BTW, does Falcon truncate the keys always behind the scene or does it
offer a custom CREATE INDEX extension for that purpose? We were thinking
about the latter.


Dmitry