transaction.md

% psql -c 'create table t (x integer not null)'
CREATE TABLE
% psql -c 'insert into t (x) values (0)'
INSERT 0 1
% psql -c 'select * from t'
 x
---
 0
(1 row)

% cat 1.sql
begin;
select x from t for update;
delete from t;
select pg_sleep(10); -- perform some tasks
insert into t (x) values (1);
commit;
% psql -f 1.sql &
[1] 25215
BEGIN
 x
---
 0
(1 row)

DELETE 1

% psql -c 'select x from t for update'
 pg_sleep
----------

(1 row)

INSERT 0 1
 x
---
COMMIT
(0 rows)

[1]  + done       psql -f 1.sql