On 31.05.2011 01:07, Alexander Korotkov wrote:
In gist_box_penalty function floating point error in line *result = (float) (size_box(ud) - size_box(origentry->key)); sometimes makes *result a very small negative number. I beleive that best place to fix it is gistpenalty function. The attached patch makes this function treating negative number from user's penalty as zero. I didn't find mention of negative penalty value in documentation. So, AFAICS such behaviour shouldn't break anything. After the patch index performance is ok.
Yeah, there seems to be a hidden assumption that the return value of the penalty function is always >= 0. The logic in gistchoose() in particular seems to assume that, by using < 0 to mean uninitialized slots in the which_grow array.
The documentation should be fixed too. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
