Csaba Nagy wrote:
> session_1=> create table test (col smallint primary key);
> NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index
> "test_pkey" for table "test"
> CREATE TABLE
> session_1=> begin;
> BEGIN
> cnagy=> insert into test values (1);
> INSERT 165068987 1
>
> session_2=> begin;
> BEGIN
> session_2=> insert into test values (1);
>
> [session_2 is now waiting]
This only happens because of the unique index. There's no predicate
locking involved. The btree code goes some lengths to make this work;
it would be probably simple to modify this to support MERGE or REPLACE
on the limited cases where there's a UNIQUE index. Tom has already said
this twice (on this thread only; he has already said it before IIRC.)
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
