Re: the IN clause saga

Felipe Schnack wrote:
>   Am I the only the only one who doesn't like the idea of the driver parsing SQL statements (to check if there is a
INclause) 
>

Mind that this is only necessary for backward compatibility.  With 7.4
and the V3 protocol you just send an array and the backend sorts it out.





> On Tue, 22 Jul 2003 10:41:22 -0400
> Fernando Nasser <[email protected]> wrote:
>
>
>>Oliver Jowett wrote:
>>
>>>On Tue, Jul 22, 2003 at 09:05:45AM -0400, Fernando Nasser wrote:
>>>
>>>
>>>>Thanks for summarizing it Oliver.
>>>>
>>>>I've asked Tom Lane about the backend behavior and he informed me that:
>>>>
>>>>1) 7.4 backends do support parameters in the IN predicate, as ($1, $2,
>>>>$3) (i.e., our (?, ?, ?) syntax).
>>>>
>>>>2) 7.4 backends have a PostgreSQL specific extension that allows you to
>>>>fill the IN predicate with a list: ($1)  (i.e., our (?) ).  One has to
>>>>pass a PostgreSQL array, like integer[] to fill the list.  Note that the
>>>>parenthesis is already in place, it is not generated by the ? expansion.
>>>
>>>
>>>I assume this is only when you're doing a PREPARE/EXECUTE?
>>>
>>
>>yes.
>>
>>
>>>>The feature 2 in 7.4 backends is of limited use as the planner does not
>>>>know about the list, so the generated plan will not be as good as if you
>>>>pass the list with fixed values since the beginning.  But an improvement
>>>>for this can be attempted for 7.5.
>>>
>>>
>>>Hm, then it sounds like the right solution is to have setArray() expand as
>>>the guts of an IN clause when the backend is <7.4 or server prepares are
>>>off, and the parameter is in a query of the form "... IN (?)", and as a
>>>normal array otherwise.
>>>
>>
>>That is _exactly_ what I am proposing (option 2 of your summary)
>>
>>
>>
>>--
>>Fernando Nasser
>>Red Hat Canada Ltd.                     E-Mail:  [email protected]
>>2323 Yonge Street, Suite #300
>>Toronto, Ontario   M4P 2C9
>>
>>
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>
>


--
Fernando Nasser
Red Hat Canada Ltd.                     E-Mail:  [email protected]
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9