Re: [HACKERS] cidr - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: [HACKERS] cidr
Date
Msg-id 199807212109.RAA04863@candle.pha.pa.us
Whole thread Raw
In response to Re: [HACKERS] cidr  (Paul A Vixie <vixie@vix.com>)
List pgsql-hackers
> My question is, do those types have an internal framing format with an outer
> length and an inner opaque structure, or does each one have a "length"
> accessor to which an opaque structure is passed?  In the former case, we'll
> be burning more space on a length indicator even though the address family
> and prefix length are in the opaque part of the structure.  In the latter
> case, there's no big deal at all since given the address family and prefix
> length, an accessor can tell the type system the size of a particular datum.

The length is on every field.  atttypmod is a fixed value stored in the
attribute table, and is used to modify the handling of all value in that
column.  We currently only use it for char(3)/varchar(30), etc.

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