Re: History of WAL_LEVEL (archive vs hot_standby) - Mailing list pgsql-hackers

On Fri, Mar 28, 2014 at 12:16 PM, David Johnston <polobo@yahoo.com> wrote:
>
> Slightly tangential but are the locking operations associated with the
> recent bugfix generated in both (all?) modes or only hot_standby?  I thought
> it strange that transient locking operations were output with WAL though I
> get it if they are there to support read-only queries.
>

IIUC, XLogStandbyInfoActive() is used at places where it is thought
that the WAL record being written at that point would be required on a
standby for correct hot standby operation (comments at these call
sites are helpful).

/* Do we need to WAL-log information required only for Hot Standby and
logical replication? */
#define XLogStandbyInfoActive() (wal_level >= WAL_LEVEL_HOT_STANDBY)

--
Amit