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From Zhenya Stanilovsky <arzamas...@mail.ru.INVALID>
Subject Re: Case sensitive indexes question.
Date Fri, 30 Nov 2018 12:34:29 GMT

Vladimir, thank you for clarification.
i.e. you suggest creating two tickets:
1. for performance log message.
2. restrict such indexes creation.
is it correct ?
what about flag disabled by default, thus nothing would be broken?
>Пятница, 30 ноября 2018, 15:15 +03:00 от Evgeniy Stanilovskiy <estanilovskiy@gridgain.com>:
>------- Forwarded message -------
>From: "Vladimir Ozerov" < vozerov@gridgain.com >
>To: dev < dev@ignite.apache.org >
>Subject: Re: Case sensitive indexes question.
>Date: Wed, 28 Nov 2018 23:11:50 +0300
>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.
>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!

Zhenya Stanilovsky
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