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From Vladimir Ozerov <voze...@gridgain.com>
Subject Re: Case sensitive indexes question.
Date Wed, 28 Nov 2018 20:11:50 GMT
Hi Zhenya,

Answering your questions:
1) Yes, this is expected
2) This is standard rule applicable for almost all vendors and all SQL
commands - object name without quotes is normalized to some case (upper or
lower), object name in qoutes is left as is
3) Hard to say, need to experiment with it
4) We don't

Some vendors allow it (MySQL, Postgres), may be some other's don't. We
cannot restrict their usage in AI 2.x as it may break existing
applications. Neither I think we should restrict it - nothing is broken.
IMO what we do need is to inform user that he is doing something strange
and let him decide what to do. This could be a warning in the log, special
"performance suggestions" SQL view, whatever.

Vladimir.

On Wed, Nov 28, 2018 at 8:57 PM Zhenya <arzamas123@mail.ru.invalid> wrote:

> Igniters, i found that ignite allow to create multiple case sensitive
> indexes with equal fields collection, i.e. no exception and warn here:
>
> CREATE INDEX \"title_idx\" ON books (title);
> CREATE INDEX \"tiTLE_IDX\" ON books (title);
>
> 1. in this case will be created two different index structures.
> 2. documentation [1] not clarify that quotation usage will create
> different ones and quotation absence will create index name in upper
> registry.
> 3. what index, query planner would be use?
> 4. and main question: why do we need this functional?
>
> i found that other vendors not allow such indexes [2]
>
> if we can`t change this in 2.x version due to some backward compatibility
> reasons, plz show them, i have no clue why we can`t change it in near
> release versions.
>
> [1] https://apacheignite-sql.readme.io/docs/create-index
> [2]
>
> https://oracle-base.com/articles/12c/multiple-indexes-on-same-set-of-columns-12cr1
>
> thanks!
>

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