Re: [SQL] Duplicate tuples with unique index

> Bruce thinks that the pg_upgrade script will ensure that the system-
> table tuples are all in frozen states (by VACUUMing them). I don't
> trust it worth a dime, myself. Maybe it will work, but it hasn't been
> proven in the field. So, if you'd like to try it, by all means do so
> --- but make a pg_dump backup first! And let us know whether you have
> problems or not!

I see what you are saying. If a table created as part of the new
pg_dump schema create matches a transaction that aborted in the old
database, the table would be invalid. However, as you mentioned, once
the tuple is marked as committed/rolled back, it doesn't consult.

Basically, I was surprised pg_upgrade worked at all in any of the
releases. It seems too good to be true. However, I have received very
few problem reports about its use, and it does get used.

--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
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