Re: WORM and Read Only Tables (v0.1)

Simon Riggs  writes:
> This command will place a ShareLock (only) on the table, preventing
> anybody from writing to the table while we freeze it. The ShareLock is
> incompatible with any transaction that has written to the table, so when
> we acquire the lock all writers to the table will have completed. We
> then run the equivalent of a VACUUM FREEZE which will then be able to
> freeze *all* rows in one pass (rather than all except the most
> recent).

This breaks MVCC.  The fact that a transaction has completed is not
license to discard tuple xmin immediately.
		regards, tom lane