Обсуждение: OIDs / noOIDs tables?
Hi As for version 7.2 postgres supports tables wothout OID. So I have 10 Gb database and I would like to upgrade it to 7.2 to make the tables without oids in order to save disc space. I made a test. I created one table with oids and another without oids and dumped the same data in both of them but there was no difference in table sizes. Btw the size is the same as the size of the original table in the previous release i use (7.0.3). Can anybody tell me why? Thanks in advance! regards, hal __________________________________________________ Do You Yahoo!? Try FREE Yahoo! Mail - the world's greatest free email! http://mail.yahoo.com/
Heni Lolov wrote: > Hi > > As for version 7.2 postgres supports tables wothout OID. So I have 10 Gb > database and I would like to upgrade it to 7.2 to make the tables without oids > in order to save disc space. I made a test. I created one table with oids and > another without oids and dumped the same data in both of them but there was no > difference in table sizes. > Btw the size is the same as the size of the original table in the previous > release i use (7.0.3). Yes, tables are the same size. The only difference is that the oid counter doesn't increase for INESRTs. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
Heni Lolov writes: > As for version 7.2 postgres supports tables wothout OID. So I have 10 Gb > database and I would like to upgrade it to 7.2 to make the tables without oids > in order to save disc space. I made a test. I created one table with oids and > another without oids and dumped the same data in both of them but there was no > difference in table sizes. Did you actually change the CREATE TABLE commands to say WITHOUT OIDS? By default, OID columns are still created. -- Peter Eisentraut peter_e@gmx.net
--On lundi 11 mars 2002 08:10 -0800 Heni Lolov <hal_bg@yahoo.com> wrote: > As for version 7.2 postgres supports tables wothout OID. So I have 10 Gb > database and I would like to upgrade it to 7.2 to make the tables without > oids in order to save disc space. I made a test. I created one table > with oids and another without oids and dumped the same data in both of > them but there was no difference in table sizes. > Btw the size is the same as the size of the original table in the previous > release i use (7.0.3). > > Can anybody tell me why? > Thanks in advance! well, I had a 7.1.3 database, and I switched over to 7.2 without oids, here's the change : 7.1.3 : 4367448 /opt/pg/data/base/18721 7.2 : 3551340 /opt/pgsql/data/base/16567 and there's a bit more info in the 7.2 database now... so I believe that without oids give you a bit smaller databases. -- Mathieu Arnold
Mathieu Arnold <mat@mat.cc> writes:
> ... there's a bit more info in the 7.2 database now...
> so I believe that without oids give you a bit smaller databases.
OIDs vs. no OIDs makes absolutely *zero* difference in disk space.
The tuple header overhead is the same either way.
(Well, okay, it saves you one pg_attribute row per OID-less table.
Wow...)
The only reason for the no-OIDs feature is to postpone wraparound
of the OID counter.
regards, tom lane
PS: probably your space savings from updating to 7.2 is a transient
result of having rebuilt the indexes.