John Wells wrote: > On 12/4/07, Alvaro Herrera <alvherre@xxxxxxxxxxxxxx> wrote: > > John Wells wrote: > > > On 12/4/07, Alvaro Herrera <alvherre@xxxxxxxxxxxxxx> wrote: > > > > There are no field separators. Perhaps you could extract some useful > > > > info with pg_filedump, which you can grab at > > > > http://sources.redhat.com/rhdb > > > > > > So is it simply field width? Can one count the number of bytes based > > > on native datatype length and determine field start/end? > > > > Yes. For variable length types, there is a 4-byte length word at the > > start of the field (unless you are using 8.3 which introduces more > > compact representations in some cases). > > Oh fun...what about record separators? I think I could live with doing > it by name and id. Since name is the last field in the table, and id > is the first, one could assume that it looks something like this: > > 1rst record name | record separator | 2nd record id | etc, etc > > If I could split on that record separator I might be able to get what I'm after. There are no record separators either. Records are stored following offsets which are stored in a fixed-size array at the start of each page, called "line pointers". Have a look at what pg_filedump shows you for interpreted output. Maybe you can get away with your idea, keeping in mind that record separators are just not there. -- Alvaro Herrera http://www.flickr.com/photos/alvherre/ "Aprender sin pensar es inútil; pensar sin aprender, peligroso" (Confucio) ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
