On Sat, 17 Jun 2006, paolo romano wrote:
When a transaction enters (successfully) the prepared state it only retains its exclusive locks and releases any shared locks (i.e. multixacts)... or, at least, that's how it should be in principle according to serializiaton theory, i haven't yet checked out if this is what is done in postgresql .
In PostgreSQL, shared locks are not taken when just reading data. They're used to enforce foreign key constraints. When inserting a row to a table with a foreign key, the row in the parent table is locked to keep another transaction from deleting it. It's not safe to release the lock before end of transaction.
- Heikki ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
