Re: [HACKERS] Re: pgsql: Make CheckRequiredParameterValues() depend upon correct

On Fri, 2010-04-23 at 16:44 -0400, Tom Lane wrote:

> There's no connection at all between what the GUC state
> was at shutdown and what it might be after starting again.
> 
> A design that might work is
> (1) store the active value of wal_mode in pg_control (but NOT as part of
> the last-checkpoint-record image).
> (2) invent a new WAL record type that is transmitted when we change
> wal_mode.
> 
> Then, slaves could check whether the master's wal_mode is high enough
> by looking at pg_control when they start plus any wal_mode_change
> records they come across.

Seems OK on standby side. On the primary there are some other points,
mentioned on other thread as to when we can change wal_mode.

> If we did this then we could get rid of those WAL record types that were
> added to signify that information had been omitted from WAL at specific
> times.

Please.

-- 
 Simon Riggs           www.2ndQuadrant.com