Re: Very specialised query - Mailing list pgsql-performance

From Matthew Wakeling
Subject Re: Very specialised query
Date
Msg-id alpine.DEB.2.00.0904011924150.21772@aragorn.flymine.org
Whole thread Raw
In response to Re: Very specialised query  (Matthew Wakeling <matthew@flymine.org>)
Responses Re: Very specialised query  (Matthew Wakeling <matthew@flymine.org>)
List pgsql-performance
On Wed, 1 Apr 2009, Matthew Wakeling wrote:
> So, I have written a plpgsql function to calculate overlaps. It works
> reasonably quickly where there aren't that many overlaps. However, it seems
> to go very slowly when there are a large number of rows to return.

In plpgsql, what happens about memory allocation? It's just, I'm
generating and throwing away an awful lot of arrays. When do they get
unallocated?

Also, if I assign a variable (or an element of an array) to be the
contents of another variable (which may be a primitive, array, or row),
does it copy the contents or do it by reference?

Matthew

--
 For those of you who are into writing programs that are as obscure and
 complicated as possible, there are opportunities for... real fun here
                                        -- Computer Science Lecturer

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