Re: Re: new patch of MERGE (merge_204) & a question about duplicated ctid

On Jan3, 2011, at 17:21 , Robert Haas wrote:
> On Mon, Jan 3, 2011 at 11:08 AM, Heikki Linnakangas
>> In serializable mode you get a serialization error.
> 
> I don't think this part is true.  You can certainly do this:
> 
> CREATE TABLE test (a int);
> BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
> SELECT * FROM test;
> <in another session, insert (1) into test>
> LOCK TABLE test IN SHARE MODE; -- or just LOCK TABLE test, if you prefer
> SELECT * FROM test;  -- still ain't there
> INSERT INTO test VALUES (1);

In SERIALIZABLE mode, you need to take any table-level locks before obtaining
a snapshot. There's even a warning about this in the docs somewhere IIRC...

best regards,
Florian Pflug