Hi, PFC, PFC wrote: > You need to do some processing to know how many rows the function > would return. > Often, this processing will be repeated in the function itself. > Sometimes it's very simple (ie. the function will RETURN NEXT each > element in an array, you know the array length...) > Sometimes, for functions returning few rows, it might be faster to > compute the entire result set in the cost estimator. I know, but we only have to estmiate the number of rows to give a hint to the query planner, so we can use lots of simplifications. E. G. for generate_series we return ($2-$1)/$3, and for some functions even constant estimates will be good enough. > - please execute me and store my results in a temporary storage, > count the rows returned, and plan the outer query accordingly That's an interesting idea. Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
