"D. Richard Hipp" <[EMAIL PROTECTED]> wrote
in message news:[EMAIL PROTECTED]
> On Sep 21, 2008, at 8:51 AM, Russ Leighton wrote:
>
>> I am interested in ... a way
>> to constraint/control index selection on queries.
>>
>
> What other SQL database engines have this capability and what syntax
> do
Personally, I like the Mysql syntax best of the below links. Seems
natural and unobtrusive (unlike 'hints').
On Sep 21, 2008, at 12:12 PM, Alex Scotti wrote:
> not surprisingly, the db2 approach is the only one that seems to
> follow the "ideal" of the relational dbms. looks like you get to
not surprisingly, the db2 approach is the only one that seems to
follow the "ideal" of the relational dbms. looks like you get to
provide to the engine information about your data, rather than
describing to the engine what steps it's supposed to take. hints
that directly influence query
A reason I think such functionality would be ideal for sqlite is that
it avoids the need for a fancy query plan optimizer. The user would
have a way to direct the query plan if the simple and obvious plan is
suboptimal.
On Sep 21, 2008, at 11:36 AM, "D. Richard Hipp" <[EMAIL PROTECTED]>
D. Richard Hipp wrote:
> On Sep 21, 2008, at 8:51 AM, Russ Leighton wrote:
>
>> I am interested in ... a way
>> to constraint/control index selection on queries.
>>
>
> What other SQL database engines have this capability and what syntax
> do they use?
Richard,
Hope this are useful:
Oracle:
Oracle has 'hints' which live in the comments emdedded in the select.
Google 'oracle hint use index'. The 3rd hit down my result list has a
nice overview.(I'd send the link but this stupid iPhone has no cut-n-
paste). I think that hints are really ugly. Not sure about the other
big dmbs.
On Sep 21, 2008, at 8:51 AM, Russ Leighton wrote:
> I am interested in ... a way
> to constraint/control index selection on queries.
>
What other SQL database engines have this capability and what syntax
do they use?
D. Richard Hipp
[EMAIL PROTECTED]
On Sep 19, 2008, at 6:30 PM, D. Richard Hipp wrote:
>
> On Sep 19, 2008, at 5:47 PM, Russ Leighton wrote:
>
>>
>> Observation 1: Group by (in my case) is faster w/out using the index
>> than with using the index by 10X
>>
>> In my app I have a table-
>>
>> create table foo(k1integer ,k2
It would be very nice to have a way to explicitly control index use.
I'm going to test my theory this weekend but I think if the index is
not cached and the data large then the group by is faster without the
index. If this is the case I have a real issue. I need the index for
other queries
On Fri, Sep 19, 2008 at 10:47:33PM -0400, Russ Leighton scratched on the wall:
> What about the null values for the aggregation keys when I put a '+'
> to disable the index? Is that 'as designed'?
The "+" operator gets rid of type-affinities, and that can lead to
unexpected results. I'm
On Sep 19, 2008, at 5:47 PM, Russ Leighton wrote:
>
> Observation 1: Group by (in my case) is faster w/out using the index
> than with using the index by 10X
>
> In my app I have a table-
>
> create table foo(k1integer ,k2 integer,k3 integer,...);
> create index foo_idx on foo(k1,k2,k3);
>
>
Observation 1: Group by (in my case) is faster w/out using the index
than with using the index by 10X
In my app I have a table-
create table foo(k1integer ,k2 integer,k3 integer,...);
create index foo_idx on foo(k1,k2,k3);
when I do-
select k1,k2,sum() as s,count(1) as c from foo
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