Re: [HACKERS] tables > 1 gig

> Bruce Momjian <maillist@candle.pha.pa.us> writes:
> >> Then we'd better fix the underlying problem.  We can't change
> >> RELSEG_SIZE for a minor release, unless you want to give up the
> >> principle of not forcing initdb at minor releases.
> > Why can't we increase it?
> Consider a 1.5-gig table.  6.5 will store it as one gig in file "table",
> one-half gig in file "table.1".  Now recompile with larger RELSEG_SIZE.
> The file manager will now expect to find all blocks of the relation in
> file "table", and will never go to "table.1" at all.  Presto, you lost
> a bunch of data.
> Bottom line is just as it says in the config.h comments: you can't
> change either BLCKSZ or RELSEG_SIZE without doing initdb.

Sorry for backing up so far on this thread...

Would it be possible to make BLCKSZ and/or RELSEG_SIZE (the latter
perhaps the most important, and perhaps the easiest?) a configurable
parameter which is read out of a global variable for each database? If
so, we could later think about moving it, along with things like
"default character set", to pg_database as per-db information, and
make it an option on CREATE DATABASE. That kind of thing might make
in-place upgrades easier too.
                    - Thomas

-- 
Thomas Lockhart                lockhart@alumni.caltech.edu
South Pasadena, California