Re: Re: [COMMITTERS] Can not create more than 32766 databases in ufs file system. - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Re: [COMMITTERS] Can not create more than 32766 databases in ufs file system.
Date
Msg-id 20090912201704.GS17756@tamriel.snowman.net
Whole thread Raw
In response to Re: Re: [COMMITTERS] Can not create more than 32766 databases in ufs file system.  (Mark Mielke <mark@mark.mielke.cc>)
Responses Re: Re: [COMMITTERS] Can not create more than 32766 databases in ufs file system.
Re: Re: [COMMITTERS] Can not create more than 32766 databases in ufs file system.
List pgsql-hackers
* Mark Mielke (mark@mark.mielke.cc) wrote:
> There is no technical requirement for PostgreSQL to separate data in
> databases or tables on subdirectory or file boundaries. Nothing wrong
> with having one or more large files that contain everything.

Uhh, except where you run into system limitations on file size (eg- a 2G
max file size..).  You'll note PG creates files up to 1G and then splits
them into separate files.  It's not done just because it's fun.

> I guess I'm not seeing how using 32k tables is a sensible model.

For one thing, there's partitioning.  For another, there's a large user
base.  32K tables is, to be honest, not all that many, especially for
some of these databases which reach into the multi-TB range..

> So yes,
> things can be done to reduce the cost - but it seems like something is
> wrong if this is truly a requirement.

I have no idea what you've been working with, but I hardly think it
makes sense for PG to consider over 32k tables as not worth supporting.

> There are alternative models of
> storage that would not require 32k tables, that likely perform better.

Eh?  You would advocate combining tables for no reason other than you
think it's bad to have alot?

> Do you agree with me that having 32k open file descriptors (or worse,
> open on demand file descriptors that need to be re-opened many times) is
> a problem?

Nope.

> Looking at PostgreSQL today - I don't think it's designed to scale to
> this. Looking at SQL today, I think I would find it difficult to justify
> creating a solution that requires this capability.

Actually, I find that PG handles it pretty well.  And we used to be an
Oracle shop.
Thanks,
    Stephen

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