On Thu, Dec 21, 2000 at 09:41:54PM +0000, Oliver Elphick wrote: > will trillich wrote: > >this is way OT, but debian-user has the Folks Who Know... > > > >i'm using 6.3 postgresql on potato, and would like to compress > >a wee bit-o-space out of each record by using bitwise booleans, > >instead of bytewise. > > > >there seems to be no bitwise operators to facilitate such > >testing (nor even an numerative dataset type) so i was trying > > 1. Is it actually worth jumping through hoops to save a few bytes?
2 bytes x 2,000,000 records = 4mb 16 bytes x 2,000,000 records = 32mb! > Disk space is usually cheaper than time, and, to my mind, it is > of primary importance to keep database design as simple as > possible. These sort of tricks will make your life and any > successor maintainer's life more difficult in the future. > > We aren't living in the 1960's, after all! true. trade-offs, trade-offs. hmm... > 2. If you want to do fancy stuff, you're going to need to keep > PostgreSQL up to date. There are lots and lots of bugs in 6.3 > It's definitely antediluvian! There are 7.0.3-2 debs available > for potato at http://www.samfundet.no/~tfheen/debian. Treatment > of views is greatly improved on 6.3. not postgredeluvian? :) thanks for the link! (i'm beginning to think that oliver IS postgresql...) > 3. You might find the BIT or VARBIT types of use, which have some logical > and shift operators available. They don't seem to be documented, > and there are bugs in them even at 7.0.3 (cured in 7.1). > > Operators are: > > bray=# select oprname,t1.typname as oprleft,t2.typname as oprright,oprcode > from pg_operator as o, pg_type as t1, pg_type as t2 where oprleft in (select > oid from pg_type where typname ~* 'bit') and o.oprleft = t1.oid and > o.oprright = t2.oid; > oprname | oprleft | oprright | oprcode > ---------+---------+----------+--------------- > = | bit | bit | biteq > <> | bit | bit | bitne > < | bit | bit | bitlt > > | bit | bit | bitgt > <= | bit | bit | bitle > >= | bit | bit | bitge > & | bit | bit | bitand > | | bit | bit | bitor > # | bit | bit | bitxor > << | bit | int4 | bitshiftleft > >> | bit | int4 | bitshiftright > || | bit | bit | bitcat > = | varbit | varbit | varbiteq > <> | varbit | varbit | varbitne > < | varbit | varbit | varbitlt > > | varbit | varbit | varbitgt > <= | varbit | varbit | varbitle > >= | varbit | varbit | varbitge > (18 rows) > > Bit constants are specified like this: B'011001' cool. thanks! -- There are only two places in the world where time takes precedence over the job to be done. School and prison. --William Glasser [EMAIL PROTECTED] *** http://www.dontUthink.com/ volunteer to document your experience for next week's newbies -- http://www.eGroups.com/messages/newbieDoc
