Re: Big 7.1 open items - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Big 7.1 open items
Date
Msg-id 16985.961038832@sss.pgh.pa.us
Whole thread Raw
In response to Re: Big 7.1 open items  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Big 7.1 open items  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> That was my point --- that in doing this change, we are taking on more
> TODO items, that may detract from our main TODO items.

True, but they are also TODO items that could be handled by people other
than the inner circle of key developers.  The actual rejiggering of
table-to-filename mapping is going to have to be done by one of the
small number of people who are fully up to speed on backend internals.
But we've got a lot more folks who would be able (and, hopefully,
willing) to design and code whatever tools are needed to make the
dbadmin's job easier in the face of the new filesystem layout.  I'd
rather not expend a lot of core time to avoid needing those tools,
especially when I feel the old approach is fatally flawed anyway.

> Even gdb shows us the filename/tablename in backtraces.  We are never
> going to be able to reproduce that.

Backtraces from *what*, exactly?  99% of the backend is still going
to be dealing with the same data as ever.  It might be that poking
around in fd.c will be a little harder, but considering that fd.c
doesn't really know or care what the files it's manipulating are
anyway, I'm not convinced that this is a real issue.

> I guess I don't consider table schema commands inside transactions and
> such to be as big an items as the utility features we will need to
> build.

You've *got* to be kidding.  We're constantly seeing complaints about
the fact that rolling back DROP or RENAME TABLE fails --- and worse,
leaves the table in a corrupted/inconsistent state.  As far as I can
tell, that's one of the worst robustness problems we've got left to
fix.  This is a big deal IMHO, and I want it to be fixed and fixed
right.  I don't see how to fix it right if we try to keep physical
filenames tied to logical tablenames.

Moreover, that restriction will continue to hurt us if we try to
preserve it while implementing tablespaces, ANSI schemas, etc.
        regards, tom lane


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