Re: [HACKERS] Parallel regress tests (was Re: FOREIGN KEY andshift/reduce)

Tom Lane wrote:

> I like the tcl/expect idea a lot. We'd have to upgrade our tcl
> interface to support asynchronous queries (ie, send query then do other
> stuff until answer arrives); AFAIR it can't handle that now. But that'd
> be well worth doing anyway...

O.K.

The multi session test tool, written in Tcl, is ready. Where
should it go and how should it be named? I think it wouldn't
be a bad idea to have it in a place where it can be used from
any location, instead of putting it into the regression dir.
Maybe install it into bin?

Just to show a little:

# ----
# Multi session test suite
# ----

# ----
# Session 1 starts a transaction and deletes all rows from t1
# ----
/ connect A
begin;
select * from t1;
delete from t1;
/ wait A

# ----
# Session 2 tries to select all from t1 for update - should block
# ----
/ connect B
begin;
select * from t1 for update of t1;
commit;
/ wait B

# ----
# Now session 1 rolls back ...
# ----
/ use A
rollback;
/ wait A

# ----
# ... what must release session 2
# ----
/ wait B

/ close A
/ close B

The above input produces this output:

# ----
# Multi session test suite
# ----
# ----
# Session 1 starts a transaction and deletes all rows from t1
# ----
(A) QUERY: begin;
(A) QUERY: select * from t1;
(A) a1|b1|c1
(A) --+--+-----
(A) 2| 2|key 2
(A) 3| 3|key 3
(A) 8| 8|key 7
(A) (3 rows)
(A)
(A) QUERY: delete from t1;
# ----
# Session 2 tries to select all from t1 for update - should block
# ----
(B) QUERY: begin;
(B) QUERY: select * from t1 for update of t1;
*** Session of connection B seems locked
# ----
# Now session 1 rolls back ...
# ----
(A) QUERY: rollback;
# ----
# ... what must release session 2
# ----
(B) a1|b1|c1
(B) --+--+-----
(B) 2| 2|key 2
(B) 3| 3|key 3
(B) 8| 8|key 7
(B) (3 rows)
(B)
(B) QUERY: commit;

The default time for the "wait" command is 5 seconds, but can
be specified explicitly as "wait A 10". Session names can of
course be longer than one character.

The script stopped at session B's SELECT ... FOR UPDATE, and
correctly continued with the *** message 5 seconds later. As
you might have noticed, it doesn't matter that the COMMIT of
session 2 was placed directly after the SELECT. If the
session hangs, all queries are internally buffered.

Jan

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