Optimizer overrides - functional spec

[Mamta Satoor <ms...@gmail.com>]

Hi,
 I am looking at implementing optimizer overrides in Derby for 10.2 release. 
Derby engine in fact already supports some optimizer overrides but they are 
not user visible. I have attached the functional spec for more information. 
Let me know if anyone has any comments.
 thanks,
Mamta

Re: Optimizer overrides - functional spec

[Øystein Grøvlen <Oy...@Sun.COM>]

I have a question about the following:

        If the user will not follow --PROPERTIES syntax for specifying
        the optimizer overrides, parser will simply treat them as
        comments and ignore them. So, be careful with the syntax,
        don't leave any blanks between -- and PROPERTIES. The
        parser can always be modified to be more flexible about this
        syntax but this is what I am shooting for at this point.

Does this mean that if I have corretly written "--PROPERTIES ..", but
makes some other syntax errors later in the comment, that such errors
will not be reported, or is this only about not putting a space
between "--" and "PROPERTIES"?

-- 
Øystein

Re: Optimizer overrides - functional spec

[Mamta Satoor <ms...@gmail.com>]

Yes, you are right. Since -- comments gobble everything until the end of 
line by their definition, I didn't put anything in the functional spec for 
it. But it never hurts to be more specific to make things clearer. I would 
go ahead and put this information in the functional spec.
 thanks,
Mamta
 On 9/15/05, Jeffrey Lichtman <sw...@rcn.com> wrote: 
> 
> 
> >I am looking at implementing optimizer overrides in Derby for 10.2
> >release. Derby engine in fact already supports some optimizer
> >overrides but they are not user visible. I have attached the
> >functional spec for more information. Let me know if anyone has any 
> comments.
> 
> I assume that since the override syntax will be in comments, any
> override must be at the end of a line. For example:
> 
> FROM --PROPERTIES joinOrder = FIXED
> tab1, tab2, tab3
> 
> would work, but:
> 
> FROM --PROPERTIES joinOrder = FIXED tab1, tab2, tab3
> 
> would not work. Is that correct? If so, I think it should be
> explained in the functional spec.
> 
> 
> - Jeff Lichtman
> swazoo@rcn.com
> Check out Swazoo Koolak's Web Jukebox at
> http://swazoo.com/
> 
>

Re: Optimizer overrides - functional spec

[Jeffrey Lichtman <sw...@rcn.com>]

>I am looking at implementing optimizer overrides in Derby for 10.2 
>release. Derby engine in fact already supports some optimizer 
>overrides but they are not user visible. I have attached the 
>functional spec for more information. Let me know if anyone has any comments.

I assume that since the override syntax will be in comments, any 
override must be at the end of a line. For example:

FROM --PROPERTIES joinOrder = FIXED
     tab1, tab2, tab3

would work, but:

FROM --PROPERTIES joinOrder = FIXED tab1, tab2, tab3

would not work. Is that correct? If so, I think it should be 
explained in the functional spec.


                        -        Jeff Lichtman
                                 swazoo@rcn.com
                                 Check out Swazoo Koolak's Web Jukebox at
                                 http://swazoo.com/ 

Re: Optimizer overrides - functional spec

[Mamta Satoor <ms...@gmail.com>]

I have entered entered Derby-573 for this and attached the updated spec 
(with Jeff's comments) to the JIRA entry.
 thanks,
Mamta

 On 9/15/05, Daniel John Debrunner <dj...@debrunners.com> wrote: 
> 
> Mamta Satoor wrote:
> 
> > Hi,
> >
> > I am looking at implementing optimizer overrides in Derby for 10.2
> > release. Derby engine in fact already supports some optimizer overrides
> > but they are not user visible. I have attached the functional spec for
> > more information. Let me know if anyone has any comments.
> 
> Can you entry a Jira entry for this and attach the spec to it.
> 
> Thanks,
> Dan.
> 
>

Re: Optimizer overrides - functional spec

[Daniel John Debrunner <dj...@debrunners.com>]

Mamta Satoor wrote:

> Hi,
>  
> I am looking at implementing optimizer overrides in Derby for 10.2
> release. Derby engine in fact already supports some optimizer overrides
> but they are not user visible. I have attached the functional spec for
> more information. Let me know if anyone has any comments.

Can you entry a Jira entry for this and attach the spec to it.

Thanks,
Dan.