Gregory Stark wrote: > Bruce Momjian <[EMAIL PROTECTED]> writes: > > > I think it would be good to see if we can extend the varlena data types > > to support a shorter header for storing short byte values. Looking at > > the header now we have: > > This isn't the first time we've been down that route. There were some > extensive discussions a while back. I think there were even patches. > I don't remember why it was eventually rejected. I suspect it simply got too > complex. > > But I think this is a dead-end route. What you're looking at is the number "1" > repeated for *every* record in the table. And what your proposing amounts to > noticing that the number "4" fits in a byte and doesn't need a whole word to > store it. Well sure, but you don't even need a byte if it's going to be the > same for every record in the table. > > If someone popped up on the list asking about whether Postgres compressed > their data efficiently if they stored a column that was identical throughout > the whole table you would tell them to normalize their data.
I am confused. You don't want to shrink the header but instead compress duplicate values in the same row to a single entry? -- Bruce Momjian [EMAIL PROTECTED] EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(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
