Re: [PATCHES] Auto create (top level) directory for create tablespace

2007-12-16 Thread Peter Eisentraut
Tom Lane wrote:
 Ignoring this point is actually a fine recipe for destroying your data;
 see Joe Conway's report a couple years back about getting burnt by a
 soft NFS mount.  If the DB directory is not there, auto-creating it is
 a horrible idea.

Yes, this would be equivalent to the old behavior of the Red Hat RPMs that 
automatically performed initdb if the data directory is missing.  Thankfully, 
that has been abolished.

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/

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Re: [PATCHES] Auto create (top level) directory for create tablespace

2007-12-15 Thread Tom Lane
Mark Kirkwood [EMAIL PROTECTED] writes:
 I thought it made sense for CREATE TABLESPACE to attempt to create the 
 top level location directory -

I thought we had deliberately made it not do that.  Auto-recreate during
replay sounds even worse.  The problem is that a tablespace would
normally be under a mount point, and auto-create has zero chance of
getting such a path right.

Ignoring this point is actually a fine recipe for destroying your data;
see Joe Conway's report a couple years back about getting burnt by a
soft NFS mount.  If the DB directory is not there, auto-creating it is
a horrible idea.

regards, tom lane

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Re: [PATCHES] Auto create (top level) directory for create tablespace

2007-12-15 Thread Mark Kirkwood

Tom Lane wrote:

Mark Kirkwood [EMAIL PROTECTED] writes:
  
I thought it made sense for CREATE TABLESPACE to attempt to create the 
top level location directory -



I thought we had deliberately made it not do that.  Auto-recreate during
replay sounds even worse.  The problem is that a tablespace would
normally be under a mount point, and auto-create has zero chance of
getting such a path right.

Ignoring this point is actually a fine recipe for destroying your data;
see Joe Conway's report a couple years back about getting burnt by a
soft NFS mount.  If the DB directory is not there, auto-creating it is
a horrible idea.

  


Hmm - ok, unmounted filesystems could bite you. However, they could bite 
folks creating the directory manually too...(I guess you could argue it 
is less likely though).


On the replay front, the use case I was thinking about is standby 
database - the classic foot gun there is to create a tablespace on 
source box and forget to add the appropriate directory on the target 
and bang! replay fails.


It does seem to me like there are scenarios where either behavior is 
undesirable... a possible option is a configuration parameter to choose 
between auto creation or not. However I'm happy to go with the consensus 
here - if its universally deemed to be a terrible idea, then let's ditch 
the patch :-)


Best wishes

Mark

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