ERROR: tuple concurrently updated

Hello.

Testing of the concurrent access to database objects leaded to the following error:

  ERROR: tuple concurrently updated

  SQL state: XX000

According to the "PostgreSQL Error Codes" table in the documentation, "XX000" is the PostgreSQL internal error code.

How to reproduce such an error:

1. Create a table in some database and view:

create table t1 ( id int );

create temp view v1 as select * from t1;

2. Concurrent access to table t1 is performed by 2 clients (further C1 and C2) particularly in this order:

C1: begin; drop view v1;

C2: drop table t1;

C1: commit;

 And finally, transaction of the client C2 is terminated with this "expected" error.

What's wrong?