Re: [HACKERS] DROP TABLE inside transaction block

Seems like good comments on these items. Anything for TODO list here?

> =?iso-8859-1?Q?Jos=E9?= Soares <jose(at)sferacarta(dot)com> writes:
> > Seems a good solution. I have an old note about this problem.
> > What about to reject also the following commands inside transactions?
>
> > * BUGS: There are some commands that doesn't work properly
> > inside transactions. Users should NOT use the following
> > statements inside transactions:
>
> > - DROP TABLE -- in case of ROLLBACK only table structure
> > will be recovered, data will be
> > lost.
> > - CREATE VIEWS -- the behavior of the backend is unpredictable.
> > - ALTER TABLE -- the behavior of the backend is unpredictable.
> > - CREATE DATABASE -- in case of ROLLBACK will be removed references
> > from "pg_database" but directory
> > $PGDATA/databasename will not be removed.
>
> CREATE DATABASE (and presumably also DROP DATABASE) probably should
> refuse to run inside a transaction.
>
> I see no good reason that CREATE VIEW or ALTER TABLE should not work
> cleanly in a transaction. It may be that they have bugs interfering
> with that (for example, Hiroshi just pointed out that ALTER TABLE
> seems not to be locking the table, which is surely bogus).
>
> The main reason that DROP TABLE is an issue is that it alters the
> underlying Unix file structure, which means we can't just rely on the
> normal transaction mechanisms of committed/uncommitted tuples to handle
> rollback. ALTER TABLE doesn't do anything except change tuples.
> CREATE VIEW is a CREATE TABLE plus tuple changes (and while CREATE TABLE
> does alter the file structure by making a new file, we have extra code
> in there to handle rolling it back). So it seems like they oughta work.
>
> RENAME TABLE is another thing that can't currently be rolled back,
> because it renames the underlying Unix files and there's no mechanism
> to undo that. (RENAME TABLE is missing a lock too...)
>
> regards, tom lane
>
> ************
>
>

--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026