On Fri, Jul 08, 2005 at 09:38:07AM +0900, ITAGAKI Takahiro wrote: > Hans-J|rgen Schvnig <[EMAIL PROTECTED]> wrote: > > > 64-bit XIDs seem to be an overkill - the only practical impact I can see > > is an even larger tuple header (this can be an issue on large boxes too > > - at least compared to Oracle). > > I agreed, too. The changes of XIDs cannot be ignored because the overhead > will be 32bytes per tuple. > > Avoiding overheads, can XIDs/CIDs be different bit length? For example, > can XIDs/CIDs be changed to 48/16-bit or 40/24-bit?
Not unless you change the definition of HeapTupleFields (src/include/access/htup.h). Alignment concerns would probably bite you if you changed it, anyway. -- Alvaro Herrera (<alvherre[a]alvh.no-ip.org>) "Ninguna manada de bestias tiene una voz tan horrible como la humana" (Orual) ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])