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From Denis Magda <dma...@apache.org>
Subject Re: SQL: Index hints
Date Fri, 21 Apr 2017 01:25:57 GMT
Sergi, I’ve documented this feature for 2.0. Please confirm that the text below is technically
correct:

Index hints are useful in scenarios when it's known that one index is more selective for certain
queries than another and it's needed to instruct the query optimizer to choose a more efficient
execution plan. To do this trick in Apache Ignite use USE_INDEX(index_list) statement that
tells Ignite to take only one of the named indexes for query execution.

Below is an example that leverages from this capability:

SELECT * FROM table1 USE_INDEX(index_age)
  WHERE salary > 150000 AND age < 35;

—
Denis

> On Jan 23, 2017, at 12:19 PM, Denis Magda <dmagda@apache.org> wrote:
> 
> Created a ticket so that we don’t forget about this new H2 capability.
> https://issues.apache.org/jira/browse/IGNITE-4594 <https://issues.apache.org/jira/browse/IGNITE-4594>
> 
> Alexander P. feel free to assign it on yourself.
> 
> —
> Denis
> 
>> On Jan 23, 2017, at 10:05 AM, Dmitriy Setrakyan <dsetrakyan@apache.org> wrote:
>> 
>> Very cool! Would be nice to add it to Ignite.
>> 
>> On Mon, Jan 23, 2017 at 3:17 AM, Sergi Vladykin <sergi.vladykin@gmail.com>
>> wrote:
>> 
>>> Guys,
>>> 
>>> Recently in H2 we've merged a very important feature: index hints. It is an
>>> additional MySQL-like syntax:
>>> 
>>> SELECT * FROM  my_table USE INDEX (index_a) WHERE A = 1
>>> 
>>> It will be very easy to support this in Ignite.
>>> 
>>> Alex,
>>> 
>>> Since you are working on better SQL Enum support and it will require H2
>>> upgrade anyways, you can add this stuff to Ignite as well.
>>> 
>>> Sergi
>>> 
> 


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