Re: cache in plpgsql

Tom Lane wrote:

> Jan Wieck <JanWieck@Yahoo.com> writes:
>> Tom Lane wrote:
>>> Another little problem is that plpgsql doesn't really have any mechanism
>>> for invalidating cached stuff at all; it will leak memory like there's
>>> no tomorrow if we start dropping cached subplans.
> 
>> Everyone seems to look at it as a PL/pgSQL specific problem. It is not!
> 
> No, of course not, but plpgsql has issues of its own that (IMHO) should
> be solved along with the SPI-level problem.

Not sure what you mean by that. Is it the execution plan shortcut stuff 
for simple expressions (you know, the faked econtext to evaluate just a 
function call) that you want to move into SPI as well?

> 
>> As said, the idea is neither bad, nor new. And please let's not forget 
>> to add temp object detection into the dependency collector so that SPI 
>> automagically will handle temp tables used in PL/pgSQL by NOT storing 
>> prepared plans at all.
> 
> Why shouldn't we cache plans for temp tables?  They are good as long as
> the temp table exists.  AFAICS the same dependency mechanism will work
> fine for temp and regular tables.

Good point. So you mean to call the SPI functionality to mark plans for 
recompile at temp object destruction as well.


Jan

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