Amazing Speed

[Ruslan Zasukhin]

On 4/5/06 12:40 PM, "김 광열" <jkim at ex-em.com> wrote:

Hi Jeffrey,
 
> I have tested more complex SQL like below
> select * 
> from  sql_stat s,
> sql_stat t,
>         sql_stat u
> where s.sql_id = t.sql_id
> and   t.sql_id = u.sql_id;
> 
> And it takes very long(I killed after several minutes).
> 
> Is there any restriction for the number of tables
> which I can join ?

For now I have implement only Inner Join for 2 tables.
 
> If we join sql_stat(700K records) s with  sql_stat t, then return data will be
> about a million. 

yes

> And then join {the result of previous join(a million records)}
>      with  sql_stat u
> then return data might be about two million.

yes
 
> I hope the speed of tree table join doesn't take so long
> because the result set is only twice bigger than two table join.

Just I need yet patch our class JoinBuilder_3
 
> In Sort-merge join of Oracle, they are using temporary tablespace to save this
> kind of intermediate data and join the data in temp tablespace with normal
> table.

We will not use such tmp table...

So you really need 3 tables joins right now ?
I think into 2.3 we will go as is.
2.3 release should be ready in few days, we hope.

Then I will continue improve join algorithms.
Also note that OUTER JOIN also not use yet new alg.

Also I can say that I have see at least for some cases ability a lots
improve GROUP BY. Well, this is endless story :-)


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]