On Mon, 2007-04-09 at 04:24, Alexey Nalbat wrote: > Hello. > > I've encountered deadlock on postgresql 8.1. Here is the simple example. > > create table t1 ( > id1 integer primary key, > val1 integer > ); > create table t2 ( > id2 integer primary key, > id1 integer references t1 on delete cascade, > val1 integer, > val2 integer, > val3 integer > ); > insert into t1 select > generate_series(1,10) as id1; > insert into t2 select > generate_series(1,100) as id2, > generate_series(1,10) as id1; > > Then three concurrent transaction start. > > /*1*/ begin; > /*1*/ update t2 set val1=1 where id2=50; > /*1*/ update t2 set val2=2 where id2=50; > /*2*/ begin; > /*2*/ update t2 set val1=1 where id2=40; > /*2*/ update t2 set val2=2 where id2=40; > /*2*/ commit; > /*3*/ begin; > /*3*/ update t1 set val1=1 where id1=10; > /*1*/ update t2 set val3=3 where id2=50; > > Here we have deadlock for transactions 1 and 3. That's not a deadlock, transaction 3 is simply waiting for transaction 1 to commit or rollback. If you run a commit or rollback on transaction 1 then transaction 3 will then be ready to commit or rollback as needed.
