On Fri, 2009-01-02 at 13:47 -0500, Tom Lane wrote: > "Kevin Grittner" <kevin.gritt...@wicourts.gov> writes: > >> What do you mean by referential integrity? I don't believe you can > >> construct a foreign key problem at any transaction isolation level. > > > I mean that if someone attempts to maintain referential integrity with > > SQL code, without using explicit locks, it is not reliable. > > Presumably the implementation of foreign keys in PostgreSQL takes this > > into account and blocks the kind of behavior shown below. This > > behavior would not occur with true serializable transactions. > > IIRC the RI code has to fudge the normal serializable-snapshot behavior > in order to guarantee no constraint violation --- it has to be aware of > concurrent changes that would otherwise be invisible to a serializable > transaction.
...just to add that this is exactly as required by SQL Standard, i.e. RI works in Read Committed mode even within a Serializable transaction. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
