Re: [HACKERS] make async slave to wait for lsn to be replayed

On 2020-04-11 00:44, Andres Freund wrote:
> I think there's also some advantages of having it in a single statement
> for poolers. If a pooler analyzes BEGIN AFTER 'xx/xx' it could
> e.g. redirect the transaction to a node that's caught up far enough,
> instead of blocking. But that can't work even close to as easily if 
> it's
> something that has to be executed before transaction begin.
> 

I think that's a good point.

Also, I'm not sure how we'd expect a wait-for-LSN procedure to work 
inside a single-snapshot transaction. Would it throw an error inside a 
RR transaction block? Would it give a warning?

-- 
Anna Akenteva
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company