On 07.10.2011 12:19, Fujii Masao wrote:
> Hi,
>
> I found that by default WAL_DEBUG macro has been defined in
> 9.2dev and 9.1. I'm very surprised at this. Why does WAL_DEBUG
> need to be defined by default? The performance overhead
> introduced by WAL_DEBUG is really vanishingly low?
>
> WAL_DEBUG was defined in the following commit:
> 53dbc27c62d8e1b6c5253feba04a5094cb8fe046
>
> ----------------------
> Support unlogged tables.
>
> The contents of an unlogged table are WAL-logged; thus, they are not
> available on standby servers and are truncated whenever the database
> system enters recovery. Indexes on unlogged tables are also unlogged.
> Unlogged GiST indexes are not currently supported.
> ----------------------
I'm pretty sure that change was included in the commit by accident.
That said, the overhead of WAL_DEBUG probably is insignificant, as long
as you don't actually set wal_debug=on. I wonder if we should leave it
enabled.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com