Re: [GENERAL] PGXLOG variable worthwhile?

On 19 Sep 2002, Greg Copeland wrote:

> I think Marc made a pretty good case about the use of command line
> arguments but I think I have to vote with Tom.  Many of the command line
> arguments you seem to be using do sorta make sense to have for easy
> reference or to help validate your runtime environment for each
> instance.  The other side of that is, I completely agree with Tom in the
> it's a very dangerous option.  It would be begging for people to shoot
> themselves with it.  Besides, just as you can easily parse the command
> line, you can also parse the config file to out that information.  Plus,
> it really should be a very seldom used option.  When it is used, it's
> doubtful that you'll need the same level of dynamic control that you get
> by using command line options.
> 
> As a rule of thumb, if an option is rarely used or is very dangerous if
> improperly used, I do think it should be in a configuration file to
> discourage adhoc use.
> 
> Let's face it, specify XLOG location is hardly something people need to
> be doing on the fly.
> 
> My vote is config file it and no command line option!

I'd go one step further, and say that it should not be something a user 
should do by hand, but there should be a script to do it, and it would 
work this way:

If there is a DIRECTORY called pg_xlog in $PGDATA, then use that.  If 
there is a FILE called pg_xlog in $PGDATA, then that file will have the 
location of the directory stored in it.  That file will be created when 
the move_pgxlog script is run, and that script will be have all the logic 
inside it to determine how to move the pg_xlog directory safely, i.e. 
making sure there's room on the destination, setting permissions, etc...

that way, if you're dumb as a rock or smart as a rocket scientist, you do 
it the same way, and the script makes sure you don't scram your database 
in a not too bright moment.  No postgresql.conf var, no command line 
switch, a file or directory, and a script.

Seem workable?  Or am I on crack?