Andrew Dunstan <andrew@dunslane.net> writes:
> On 08/13/2014 09:01 PM, Tom Lane wrote:
>>> That's a fair question. I did a very very simple hack to replace the item
>>> offsets with item lengths -- turns out that that mostly requires removing
>>> some code that changes lengths to offsets ;-).
> What does changing to lengths do to the speed of other operations?
This was explicitly *not* an attempt to measure the speed issue. To do
a fair trial of that, you'd have to work a good bit harder, methinks.
Examining each of N items would involve O(N^2) work with the patch as
posted, but presumably you could get it down to less in most or all
cases --- in particular, sequential traversal could be done with little
added cost. But it'd take a lot more hacking.
regards, tom lane