Re: Synchronous replication, reading WAL for sending - Mailing list pgsql-hackers

From Pavan Deolasee
Subject Re: Synchronous replication, reading WAL for sending
Date
Msg-id 2e78013d0812240048x440e907aw190ecee0f47a9224@mail.gmail.com
Whole thread Raw
In response to Re: Synchronous replication, reading WAL for sending  ("Fujii Masao" <masao.fujii@gmail.com>)
Responses Re: Synchronous replication, reading WAL for sending
List pgsql-hackers
On Wed, Dec 24, 2008 at 1:50 PM, Fujii Masao <masao.fujii@gmail.com> wrote:
>
>
> And, I'm worried about the situation that the speed to generate xlog
> on the primary is higher than that to copy them to the standby. We
> might not be able to start xlog streaming forever.
>

If that's the case, how do you expect the standby to keep pace with
the primary after initial sync up ? Frankly, I myself have every doubt
that on a relatively high load setup, the standby will not be able
keep pace with the primary for two reasons:

- Lack of read ahead of data blocks (Suzuki-san's work may help this)
- Single threaded recovery

But then these are general problems which may impact any log-based replication.

Thanks,
Pavan

-- 
Pavan Deolasee
EnterpriseDB     http://www.enterprisedb.com


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