Hi,
What is a good way for efficiently getting the first k rows from a
query that also satisfy some additional condition to be determined
using Java code?
Amir
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On Mon, Oct 27, 2008 at 1:14 PM, Amir Michail <[EMAIL PROTECTED]> wrote:
> Hi,
>
> What is a good way for efficiently getting the first k rows from a
> query that also satisfy some additional condition to be determined
> using Java code?
BTW, even without this condition, the following approach is
Amir Michail wrote:
Hi,
What is a good way for efficiently getting the first k rows from a
query that also satisfy some additional condition to be determined
using Java code?
setMaxRows(int) is the standard way of doing this in JDBC, it only falls
over if you later want to retrieve rows k..(2
On Mon, Oct 27, 2008 at 5:45 PM, Daniel Noll <[EMAIL PROTECTED]> wrote:
> Amir Michail wrote:
>>
>> Hi,
>>
>> What is a good way for efficiently getting the first k rows from a
>> query that also satisfy some additional condition to be determined
>> using Java code?
>
> setMaxRows(int) is the stand
Amir Michail wrote:
It's slow with setMaxRows.
Are you sure you have the correct indexes on whatever you're using for
your condition? Try getting an explanation of your query to see what
it's actually doing.
I can confirm that the row_number() approach is slow (it's the current
best worka
Please, post the query you are running.There are queries where setMaxRows
will not be faster, for example if you do GROUP BY or ORDER BY.
On Mon, Oct 27, 2008 at 22:51, Amir Michail <[EMAIL PROTECTED]> wrote:
> On Mon, Oct 27, 2008 at 5:45 PM, Daniel Noll <[EMAIL PROTECTED]> wrote:
> > Amir Micha
On Mon, Oct 27, 2008 at 5:59 PM, Peter Ondruška
<[EMAIL PROTECTED]> wrote:
> Please, post the query you are running.
> There are queries where setMaxRows will not be faster, for example if you do
> GROUP BY or ORDER BY.
The order is important, so I'm using order by.
Amir
>
> On Mon, Oct 27, 2008
Well, in that case database engine has to read all relevant rows, then sort
and only after that it can display the first row(s).
On Mon, Oct 27, 2008 at 23:02, Amir Michail <[EMAIL PROTECTED]> wrote:
> On Mon, Oct 27, 2008 at 5:59 PM, Peter Ondruška
> <[EMAIL PROTECTED]> wrote:
> > Please, post t
On Mon, Oct 27, 2008 at 6:07 PM, Peter Ondruška
<[EMAIL PROTECTED]> wrote:
> Well, in that case database engine has to read all relevant rows, then sort
> and only after that it can display the first row(s).
Why doesn't it use the index on the column specified in order by?
Amir
>
> On Mon, Oct 2
Post the query and table and index DDL.
On Mon, Oct 27, 2008 at 23:10, Amir Michail <[EMAIL PROTECTED]> wrote:
> On Mon, Oct 27, 2008 at 6:07 PM, Peter Ondruška
> <[EMAIL PROTECTED]> wrote:
> > Well, in that case database engine has to read all relevant rows, then
> sort
> > and only after that i
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