Re: Changing column types... - Mailing list pgsql-hackers

From Thomas Lockhart
Subject Re: Changing column types...
Date
Msg-id 3CACFE0B.B670CBD9@fourpalms.org
Whole thread Raw
In response to Changing column types...  ("Christopher Kings-Lynne" <chriskl@familyhealth.com.au>)
Responses Re: Changing column types...  ("Christopher Kings-Lynne" <chriskl@familyhealth.com.au>)
List pgsql-hackers
> 1. What is the difference between abstime and timestamp - they seem to
> display equally...

abstime is four bytes with a range of +/- 68 years. timestamp is eight
bytes with a range from 4212BC to way into the future.

> 2. Since int4 and abstime are binary compatible (ie int4::abstime works), is
> there any serious problem with updating a pg_attribute row for an int4 and
> changing it to and abstime?  My experiments seem to work.

A few integer values are reserved values in abstime, to allow
implementation of infinity, -infinity, etc.
                   - Thomas


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