Tom Lane wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > However, I am not sure how useful NOT NULL is in practice because there > > are lots of columns that don't specify NOT NULL but have mostly nulls or > > mostly non-nulls, which kills our caching --- what I was hoping to do > > some day was to cache the null bitmask and offsets of the previous tuple > > and use those if the new tuple has the same null bitmask as the previous > > tuple. > > We already cache fairly effectively in cases where there are no nulls. > I'm not sure it's worth trying to do something with the idea that two > adjacent tuples might have nulls in the same places.
I was thinking of trying it and seeing how often it would be a win, because right now, when we hit a null, our cache is dead. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
