[Xapian-discuss] How many docs to feed to an RSet?

[Richard Boulton]

Matthew Somerville wrote:
> Ah, thanks, presumably a hangover from when we were using a much older 
> version of Xapian. It seems to be behaving oddly, though. With this PHP code 
> for the values of N 0, 100, 500, and 1000:
> 
>      $m = $enquire->get_mset(0, 20, N);
>      print $m->get_matches_estimated(). ' ';
> 
> I get:
>          432 453 465 510
> 
> when the actual number of results is 463. The wiki says that if the number 
> of results is less than checkatleast, get_matches_estimated() should return 
> the exact result. As I increase the first argument to get_mset() it 
> eventually starts returning the right result.
> 
> It's defaulting to collapse on value 3, in case that is doing something; if 
> I switch that off, everything returns 594, the presumably correct result 
> non-collapsed.

Which version of Xapian are you using?  There have been some bugs in the 
implementation of this - a couple were fixed in 1.0.3 and another in 
1.0.4 - if you're using 1.0.4 or 1.0.5 (or SVN HEAD), I think this is a 
  newly discovered problem.

-- 
Richard