[ZODB-Dev] RelStorage: Which tables to replicate?

[Russ Ferriday]

Stefan! This is like holding all your eyelids apart and shouting out  
for somebody with a sharp stick! ;)

Watcha gonna do when you add a third server?

er.. lemme see... Multiply all OIDs by three and allocate new OIDs  
modulo three?

Eeek!

Why not make the OID a composite of server ID and sequence?  Even if  
these were both packed in the same 64 bits, just so you keep it a  
*little bit nasty*, and then maybe just get one eye poked out!  ;)

(You could get away with a byte for the server ID, leaving masses of  
bits for the item ID.)

Best wishes!

--r


On 22 May 2008, at 14:49, Stefan H. Holek wrote:

> Hi Russ,
>
> This is correct. I should have mentioned that the two servers are  
> configured so that server A creates odd, server B even sequence  
> numbers. This makes the duplicate id error pretty mysterious, IMO ;-)
>
> Stefan
>
> On 22.05.2008, at 13:15, Russ Ferriday wrote:
>
>> I have not read the reference, but it seems that this scheme can  
>> never work without keys (OIDs) being qualified by which master they  
>> originated on. Otherwise one of the mySQLs would need to be  
>> responsible for handing out unique oids.  You need an OID  
>> origination namespace for each master.
>
> --
> Stefan H. Holek
> stefan at epy.co.at
>
>
>
>

Russ Ferriday - Topia Systems - Open Source content management with  
Plone and Zope
russf at topia.com - office: +44 2076 1777588 - mobile: +44 7789 338868 -  
skype: ferriday

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