Re: [HACKERS] parameter info?

2013-02-01 Thread Andrew Dunstan 


On 01/31/2013 11:17 PM, Tom Lane wrote:

Andrew Dunstan and...@dunslane.net writes:

What's the best way for me to find out if a given parameter of a
function is a constant? The context is that it's expensive to process,
and in most cases will in fact be a constant, so if it is in fact a
constant I'd like to process it once and stash the results.

I think we added get_fn_expr_arg_stable() for precisely that
purpose.





Thanks. That's exactly what I was looking for.

cheers

andrew


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[HACKERS] parameter info?

2013-01-31 Thread Andrew Dunstan 


What's the best way for me to find out if a given parameter of a 
function is a constant? The context is that it's expensive to process, 
and in most cases will in fact be a constant, so if it is in fact a 
constant I'd like to process it once and stash the results.


cheers

andrew


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Re: [HACKERS] parameter info?

2013-01-31 Thread Pavel Stehule 
hello

2013/2/1 Andrew Dunstan and...@dunslane.net:

 What's the best way for me to find out if a given parameter of a function is
 a constant? The context is that it's expensive to process, and in most cases
 will in fact be a constant, so if it is in fact a constant I'd like to
 process it once and stash the results.


you can look into parser tree

see src of get_fn_expr_argtype(fcinfo-flinfo, 0);

Regards

Pavel

 cheers

 andrew


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Re: [HACKERS] parameter info?

2013-01-31 Thread Tom Lane 
Andrew Dunstan and...@dunslane.net writes:
 What's the best way for me to find out if a given parameter of a 
 function is a constant? The context is that it's expensive to process, 
 and in most cases will in fact be a constant, so if it is in fact a 
 constant I'd like to process it once and stash the results.

I think we added get_fn_expr_arg_stable() for precisely that
purpose.

regards, tom lane


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