Re: XLogArchivingActive

Originally I wanted the command to be a string, and archiving to be a
boolean, but Tom wanted a single parameter, and others agreed.

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Andreas Pflug wrote:
> Simon Riggs wrote:
> > On Thu, 2006-05-25 at 17:25 +0200, Andreas Pflug wrote:
> > 
> 
> > 
> >>Currently, I have to 
> >>edit postgresql.conf and SIGHUP to "turn on archiving" configuring a 
> >>(hopefully) writable directory, do the backup, edit postgresql.conf and 
> >>SIGHUP again. Not too convenient...
> > 
> > 
> > You're doing this for pgAdmin right?
> 
> Not yet, just trying to manage a server.
> 
> > 
> > My understanding was that we had the tools now to edit the
> > postgresql.conf programmatically? 
> > 
> > Seems like its not too convenient to change the way the server operates
> > to do this, as long as we solve the SIGHUP/postgresql.conf problem. I'm
> > also not that happy about curtailing people's options on backup either:
> > if people decided they wanted to have a mixture of isolated on-line
> > backup (as you suggest), plus active archiving at other times they would
> > still have the problems you suggest.
> 
> Why?
> My suggestion is to redefine XLogArchivingActive. Currently, it tests 
> for non-null archive_command. I propose
> bool XlogArchivingActive()
> {
>     if (XLogArchiveCommand[0] == 0)
>        return false;
>     return (XLogPermanentArchive // from GUC
>        || OnlineBackupRunning()); // from pg_start_backup
> }
> 
> The people you mention simply have XLogPermanentActive=true in 
> postgresql.conf, delivering the current behaviour.
> 
> > 
> > Not sure what the edit commands are offhand, but we would need the
> > following program:
> > 
> > - edit postgresql.conf
> > - pg_reload_conf()
> > - wait 30
> > - pg_start_backup('blah')
> > - backup
> > - pg_stop_backup()
> > - unedit postgresql.conf
> > - pg_reload_conf()
> > 
> > Which could then be wrapped even more simply as
> > 
> > - pg_start_backup_online('blah')
> > - backup
> > - pg_stop_backup_online()
> 
> Editing postgresql.conf for this is ugly. In addition, 
> pg_start_backup_online would need an additional parameter, the (highly 
> machine specific) archive_command string. I'd like to see that parameter 
> untouched in postgresql.conf.
> 
> Regards,
> Andreas
> 
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