Hi list, Does this also affect if you have many NULL values in the key? So testing Not is NULL would also be affected? Cheers, Dick Kniep On Tuesday 07 February 2006 23:13, Tom Lane wrote: > jao@xxxxxxxxxxxx writes: > > Quoting Tom Lane <tgl@xxxxxxxxxxxxx>: > >> In 8.0, the descent code can do > >> either "first entry >= X" or "first entry > X", and the positioning > >> rules never need to step more than one entry to locate the desired > >> starting position (details left as exercise for the reader). > > > > What about a compound index (x, y), in which there are many y values > > for a given x? My query is "... WHERE x = ? and y = ?". > > Doesn't really matter whether the key is simple or compound --- all > that matters is whether you have multiple entries that are "equal" to > the boundary value. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend
