Re: Replication between 64/32bit systems? - Mailing list pgsql-general

From Tom Lane
Subject Re: Replication between 64/32bit systems?
Date
Msg-id 11817.1316730377@sss.pgh.pa.us
Whole thread Raw
In response to Re: Replication between 64/32bit systems?  (John R Pierce <pierce@hogranch.com>)
List pgsql-general
John R Pierce <pierce@hogranch.com> writes:
> On 09/22/11 1:35 PM, Hannes Erven wrote:
>> I'm still hoping someone would give me a clue why 32/64 bit platform
>> xlogs are (and always will?) be absolutely incompatible... ???

> because the tuple representations are different, plain and simple.

Specifically, the data alignment rules are different, so a 64-bit tuple
can have padding bytes in it in places where a 32-bit tuple doesn't.
This spills over into different numbers of tuples fitting on a page,
etc etc.

> you can run a 32bit Postgres on your 64bit platform.

Yeah, that would be the thing to do if you're stuck with replicating to
nonidentical hardware.

            regards, tom lane

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