Re: Automatic Client Failover - Mailing list pgsql-hackers

From Markus Wanner
Subject Re: Automatic Client Failover
Date
Msg-id 489831D3.3030800@bluegap.ch
Whole thread Raw
In response to Re: Automatic Client Failover  (Dimitri Fontaine <dfontaine@hi-media.com>)
Responses Re: Automatic Client Failover  (Dimitri Fontaine <dfontaine@hi-media.com>)
List pgsql-hackers
Hi,

Dimitri Fontaine wrote:
> If slave nodes were able to accept connection and redirect them to master, the 
> client wouldn't need to care about connecting to master or slave, just to 
> connect to a live node.

I've thought about that as well, but think about it this way: to protect 
against N failing nodes, you need to forward *every* request through N 
living nodes, before actually hitting the node which processes the 
query. To me, that sounds like an awful lot of traffic within the 
cluster, which can easily be avoided with automatic client failover.

(Why are you stating, that only slaves need to redirect? What is 
happening in case of a master failure?)

> So the proposal for Automatic Client Failover becomes much more simpler.

I'm arguing it's the other way around: taking down a node of the cluster 
becomes much simpler with ACF, because clients automatically reconnect 
to another node themselves. The servers don't need to care.

Regards

Markus Wanner



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