Re: Practical maximums (was Re: PostgreSQL theoretical

On Mon, 2006-08-07 at 14:51 -0500, Ron Johnson wrote:

> What would be darned useful (but only, I think, with heavy usage of
> tablespaces) is:
> $ pg_tapedump /some/database /dev/st0,/dev/st1,/dev/st2,/dev/st3

I must be missing something. What is stopping you from doing something
along the lines of:

// mux.script psuedocode
// X is the size of a stripe of data
top:
read X bytes from stdin or exit if EOF
asynchronously write those X bytes to /dev/st0
read X bytes from stdin or exit if EOF
asynchronously write those X bytes to /dev/st1
goto top

And then make an inverse script called demux.script.

Then:
$ pg_dump somedatabase | gzip -c | mux.script
To restore:
$ demux.script | gunzip -c | psql somedatabase

Would that work? Obviously you'd have to document the process well to
make sure the someone didn't get confused 12 months later trying to
restore.

You may have to do something a little more sophisticated to make it work
more generally, like adding header information to each tape that says "I
am the 2nd tape of 3".

Regards,
Jeff Davis