Re: Proposal: PageLayout footprint - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Proposal: PageLayout footprint
Date
Msg-id 48A04798.80603@enterprisedb.com
Whole thread Raw
In response to Re: Proposal: PageLayout footprint  (Zdenek Kotala <Zdenek.Kotala@Sun.COM>)
Responses Re: Proposal: PageLayout footprint  (Zdenek Kotala <Zdenek.Kotala@Sun.COM>)
List pgsql-hackers
Zdenek Kotala wrote:
> It is what I don't know. controlfile only says  "incorrect checksum in 
> control file". It seems to me that CRC computing does not work 
> correctly. I check pg_control footprint and it is same for 32/64. It 
> seems to me a false positive complain, but ...

Endianness perhaps? Per comment in ControlFileData:

>      * This data is used to check for hardware-architecture compatibility of
>      * the database and the backend executable.  We need not check endianness
>      * explicitly, since the pg_control version will surely look wrong to a
>      * machine of different endianness, but we do need to worry about MAXALIGN
>      * and floating-point format.  (Note: storage layout nominally also
>      * depends on SHORTALIGN and INTALIGN, but in practice these are the same
>      * on all architectures of interest.)


> Footprint switch should help show you why it is incompatible and also 
> protect you during development to break some structure.

Apparently the footprint switch didn't provide any insight into the 
Sparc 32/64-bit issue, so I'm not too impressed..

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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