Re: How are NULLS stored on disk for PG 7.4? - Mailing list pgsql-general

From Jan Wieck
Subject Re: How are NULLS stored on disk for PG 7.4?
Date
Msg-id 4007075C.1090706@Yahoo.com
Whole thread Raw
In response to Re: How are NULLS stored on disk for PG 7.4?  (Yannick Warnier <ywarnier@beeznest.org>)
List pgsql-general
Yannick Warnier wrote:

> Le mar 13/01/2004 à 00:43, Bruce Momjian a écrit :
>> Arnold Mavromatis wrote:
>> > Hi
>> >
>> > How are column files in a table that have been assigned null stored on disk
>> > in Postgresql 7.4?
>>
>> Each row has a bitmap showing all the NULL values on that row.
>
> Is it the same for PG 7.3?

It has always been that way. But the bitmap is only there if there is at
least one NULL value. One bit in the tuple headers flags tells if there
is a bitmap or not.


Jan

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