> (In most cases NOT NULL DEFAULT xxx fields are BOOLEAN, flags: it is not > handy to have 3-way flags.)
This is certainly not true for me. I have both nullable booleans and not-nullable, defaulted columns of other types. > So, are there plans to optimize such kind of queries? This could be done by > many ways: > > 1. Store the DEFAULT flag directly in NULL BITMAP (add a bit to NULL bitmap > not only for NULLable fields, but also for NOT NULL DEFAULT ... fields). > 2. Add another bitmap for each tuple (DEFAULT bitmap). Bit value 0 means > that there is a real value in a cell, 1 - that the value is default. Both of these options would expand storage usage by a not-inconsiderable amount. > 3. The same as (1), but always force default value to be 0 (or false or any > other values with meaning "zero") and optimize only these cases. I'm not sure there's any way to know this for an arbitrary data type. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
