Magnus Hagander <[EMAIL PROTECTED]> writes: >>> Specifically, I'm interested if I actually end up making my table any >>> smaller if I move from 64-bit integer primary key to 32-bit. >> >> Depends what else is in the row ... the overall row will get padded to >> MAXALIGN, but if you were wasting 4 bytes on alignment before, then you >> win.
> Ah, I see. Followup: Does it make a measurable performance difference > for things like join or filtering operations, in case the storage size > ends up being the same? Hard to say. int8 is pass-by-reference, which is certainly slower than pass-by-value, but you'd have to measure to see if it makes any noticeable difference in your queries. (I imagine someday we'll get around to allowing int8 to be pass-by-value on 64-bit platforms.) regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match