Re: Planning incompatibilities for Postgres 10.0

On 05/28/2013 03:36 PM, Bruce Momjian wrote:

>> The other option would be to do it on query execute but that doesn't
>> seem as efficient as it would have to be parsed each time. Although
>> it would still be better than reading the actual SQL.
>
> Well, you could do SET TRANSACTION READ ONLY, and that would prevent any
> write transactions.  You could assume it is a read query, and get the
> error and resubmit on the master if that happens, but that sounds
> inefficient.  I thought you were asking for something where you could
> submit a query and it would report back as read/write or read-only.

No I am suggesting something that before anything happens with the 
parser, the protocol knows what is up. So things like pgpool-ii don't 
even need a parser, it just knows it is a read only query because the 
protocol says so.

JD



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