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postgresql/src/test/regress/sql/transactions.sql
Tom Lane 6eb52da394 Fix handling of savepoint commands within multi-statement Query strings. 
Issuing a savepoint-related command in a Query message that contains
multiple SQL statements led to a FATAL exit with a complaint about
"unexpected state STARTED".  This is a shortcoming of commit 4f896dac1,
which attempted to prevent such misbehaviors in multi-statement strings;
its quick hack of marking the individual statements as "not top-level"
does the wrong thing in this case, and isn't a very accurate description
of the situation anyway.

To fix, let's introduce into xact.c an explicit model of what happens for
multi-statement Query strings.  This is an "implicit transaction block
in progress" state, which for many purposes works like the normal
TBLOCK_INPROGRESS state --- in particular, IsTransactionBlock returns true,
causing the desired result that PreventTransactionChain will throw error.
But in case of error abort it works like TBLOCK_STARTED, allowing the
transaction to be cancelled without need for an explicit ROLLBACK command.

Commit 4f896dac1 is reverted in toto, so that we go back to treating the
individual statements as "top level".  We could have left it as-is, but
this allows sharpening the error message for PreventTransactionChain
calls inside functions.

Except for getting a normal error instead of a FATAL exit for savepoint
commands, this patch should result in no user-visible behavioral change
(other than that one error message rewording).  There are some things
we might want to do in the line of changing the appearance or wording of
error and warning messages around this behavior, which would be much
simpler to do now that it's an explicitly modeled state.  But I haven't
done them here.

Although this fixes a long-standing bug, no backpatch.  The consequences
of the bug don't seem severe enough to justify the risk that this commit
itself creates some new issue.

Patch by me, but it owes something to previous investigation by
Takayuki Tsunakawa, who also reported the bug in the first place.
Also thanks to Michael Paquier for reviewing.

Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F6BE40D@G01JPEXMBYT05
2017-09-07 09:49:55 -04:00

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--
-- TRANSACTIONS
--
BEGIN;
SELECT *
INTO TABLE xacttest
FROM aggtest;
INSERT INTO xacttest (a, b) VALUES (777, 777.777);
END;
-- should retrieve one value--
SELECT a FROM xacttest WHERE a > 100;
BEGIN;
CREATE TABLE disappear (a int4);
DELETE FROM aggtest;
-- should be empty
SELECT * FROM aggtest;
ABORT;
-- should not exist
SELECT oid FROM pg_class WHERE relname = 'disappear';
-- should have members again
SELECT * FROM aggtest;
-- Read-only tests
CREATE TABLE writetest (a int);
CREATE TEMPORARY TABLE temptest (a int);
BEGIN;
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE, READ ONLY, DEFERRABLE; -- ok
SELECT * FROM writetest; -- ok
SET TRANSACTION READ WRITE; --fail
COMMIT;
BEGIN;
SET TRANSACTION READ ONLY; -- ok
SET TRANSACTION READ WRITE; -- ok
SET TRANSACTION READ ONLY; -- ok
SELECT * FROM writetest; -- ok
SAVEPOINT x;
SET TRANSACTION READ ONLY; -- ok
SELECT * FROM writetest; -- ok
SET TRANSACTION READ ONLY; -- ok
SET TRANSACTION READ WRITE; --fail
COMMIT;
BEGIN;
SET TRANSACTION READ WRITE; -- ok
SAVEPOINT x;
SET TRANSACTION READ WRITE; -- ok
SET TRANSACTION READ ONLY; -- ok
SELECT * FROM writetest; -- ok
SET TRANSACTION READ ONLY; -- ok
SET TRANSACTION READ WRITE; --fail
COMMIT;
BEGIN;
SET TRANSACTION READ WRITE; -- ok
SAVEPOINT x;
SET TRANSACTION READ ONLY; -- ok
SELECT * FROM writetest; -- ok
ROLLBACK TO SAVEPOINT x;
SHOW transaction_read_only; -- off
SAVEPOINT y;
SET TRANSACTION READ ONLY; -- ok
SELECT * FROM writetest; -- ok
RELEASE SAVEPOINT y;
SHOW transaction_read_only; -- off
COMMIT;
SET SESSION CHARACTERISTICS AS TRANSACTION READ ONLY;
DROP TABLE writetest; -- fail
INSERT INTO writetest VALUES (1); -- fail
SELECT * FROM writetest; -- ok
DELETE FROM temptest; -- ok
UPDATE temptest SET a = 0 FROM writetest WHERE temptest.a = 1 AND writetest.a = temptest.a; -- ok
PREPARE test AS UPDATE writetest SET a = 0; -- ok
EXECUTE test; -- fail
SELECT * FROM writetest, temptest; -- ok
CREATE TABLE test AS SELECT * FROM writetest; -- fail
START TRANSACTION READ WRITE;
DROP TABLE writetest; -- ok
COMMIT;
-- Subtransactions, basic tests
-- create & drop tables
SET SESSION CHARACTERISTICS AS TRANSACTION READ WRITE;
CREATE TABLE foobar (a int);
BEGIN;
CREATE TABLE foo (a int);
SAVEPOINT one;
DROP TABLE foo;
CREATE TABLE bar (a int);
ROLLBACK TO SAVEPOINT one;
RELEASE SAVEPOINT one;
SAVEPOINT two;
CREATE TABLE baz (a int);
RELEASE SAVEPOINT two;
drop TABLE foobar;
CREATE TABLE barbaz (a int);
COMMIT;
-- should exist: barbaz, baz, foo
SELECT * FROM foo; -- should be empty
SELECT * FROM bar; -- shouldn't exist
SELECT * FROM barbaz; -- should be empty
SELECT * FROM baz; -- should be empty
-- inserts
BEGIN;
INSERT INTO foo VALUES (1);
SAVEPOINT one;
INSERT into bar VALUES (1);
ROLLBACK TO one;
RELEASE SAVEPOINT one;
SAVEPOINT two;
INSERT into barbaz VALUES (1);
RELEASE two;
SAVEPOINT three;
SAVEPOINT four;
INSERT INTO foo VALUES (2);
RELEASE SAVEPOINT four;
ROLLBACK TO SAVEPOINT three;
RELEASE SAVEPOINT three;
INSERT INTO foo VALUES (3);
COMMIT;
SELECT * FROM foo; -- should have 1 and 3
SELECT * FROM barbaz; -- should have 1
-- test whole-tree commit
BEGIN;
SAVEPOINT one;
SELECT foo;
ROLLBACK TO SAVEPOINT one;
RELEASE SAVEPOINT one;
SAVEPOINT two;
CREATE TABLE savepoints (a int);
SAVEPOINT three;
INSERT INTO savepoints VALUES (1);
SAVEPOINT four;
INSERT INTO savepoints VALUES (2);
SAVEPOINT five;
INSERT INTO savepoints VALUES (3);
ROLLBACK TO SAVEPOINT five;
COMMIT;
COMMIT; -- should not be in a transaction block
SELECT * FROM savepoints;
-- test whole-tree rollback
BEGIN;
SAVEPOINT one;
DELETE FROM savepoints WHERE a=1;
RELEASE SAVEPOINT one;
SAVEPOINT two;
DELETE FROM savepoints WHERE a=1;
SAVEPOINT three;
DELETE FROM savepoints WHERE a=2;
ROLLBACK;
COMMIT; -- should not be in a transaction block
SELECT * FROM savepoints;
-- test whole-tree commit on an aborted subtransaction
BEGIN;
INSERT INTO savepoints VALUES (4);
SAVEPOINT one;
INSERT INTO savepoints VALUES (5);
SELECT foo;
COMMIT;
SELECT * FROM savepoints;
BEGIN;
INSERT INTO savepoints VALUES (6);
SAVEPOINT one;
INSERT INTO savepoints VALUES (7);
RELEASE SAVEPOINT one;
INSERT INTO savepoints VALUES (8);
COMMIT;
-- rows 6 and 8 should have been created by the same xact
SELECT a.xmin = b.xmin FROM savepoints a, savepoints b WHERE a.a=6 AND b.a=8;
-- rows 6 and 7 should have been created by different xacts
SELECT a.xmin = b.xmin FROM savepoints a, savepoints b WHERE a.a=6 AND b.a=7;
BEGIN;
INSERT INTO savepoints VALUES (9);
SAVEPOINT one;
INSERT INTO savepoints VALUES (10);
ROLLBACK TO SAVEPOINT one;
INSERT INTO savepoints VALUES (11);
COMMIT;
SELECT a FROM savepoints WHERE a in (9, 10, 11);
-- rows 9 and 11 should have been created by different xacts
SELECT a.xmin = b.xmin FROM savepoints a, savepoints b WHERE a.a=9 AND b.a=11;
BEGIN;
INSERT INTO savepoints VALUES (12);
SAVEPOINT one;
INSERT INTO savepoints VALUES (13);
SAVEPOINT two;
INSERT INTO savepoints VALUES (14);
ROLLBACK TO SAVEPOINT one;
INSERT INTO savepoints VALUES (15);
SAVEPOINT two;
INSERT INTO savepoints VALUES (16);
SAVEPOINT three;
INSERT INTO savepoints VALUES (17);
COMMIT;
SELECT a FROM savepoints WHERE a BETWEEN 12 AND 17;
BEGIN;
INSERT INTO savepoints VALUES (18);
SAVEPOINT one;
INSERT INTO savepoints VALUES (19);
SAVEPOINT two;
INSERT INTO savepoints VALUES (20);
ROLLBACK TO SAVEPOINT one;
INSERT INTO savepoints VALUES (21);
ROLLBACK TO SAVEPOINT one;
INSERT INTO savepoints VALUES (22);
COMMIT;
SELECT a FROM savepoints WHERE a BETWEEN 18 AND 22;
DROP TABLE savepoints;
-- only in a transaction block:
SAVEPOINT one;
ROLLBACK TO SAVEPOINT one;
RELEASE SAVEPOINT one;
-- Only "rollback to" allowed in aborted state
BEGIN;
SAVEPOINT one;
SELECT 0/0;
SAVEPOINT two; -- ignored till the end of ...
RELEASE SAVEPOINT one; -- ignored till the end of ...
ROLLBACK TO SAVEPOINT one;
SELECT 1;
COMMIT;
SELECT 1; -- this should work
-- check non-transactional behavior of cursors
BEGIN;
DECLARE c CURSOR FOR SELECT unique2 FROM tenk1 ORDER BY unique2;
SAVEPOINT one;
FETCH 10 FROM c;
ROLLBACK TO SAVEPOINT one;
FETCH 10 FROM c;
RELEASE SAVEPOINT one;
FETCH 10 FROM c;
CLOSE c;
DECLARE c CURSOR FOR SELECT unique2/0 FROM tenk1 ORDER BY unique2;
SAVEPOINT two;
FETCH 10 FROM c;
ROLLBACK TO SAVEPOINT two;
-- c is now dead to the world ...
FETCH 10 FROM c;
ROLLBACK TO SAVEPOINT two;
RELEASE SAVEPOINT two;
FETCH 10 FROM c;
COMMIT;
--
-- Check that "stable" functions are really stable. They should not be
-- able to see the partial results of the calling query. (Ideally we would
-- also check that they don't see commits of concurrent transactions, but
-- that's a mite hard to do within the limitations of pg_regress.)
--
select * from xacttest;
create or replace function max_xacttest() returns smallint language sql as
'select max(a) from xacttest' stable;
begin;
update xacttest set a = max_xacttest() + 10 where a > 0;
select * from xacttest;
rollback;
-- But a volatile function can see the partial results of the calling query
create or replace function max_xacttest() returns smallint language sql as
'select max(a) from xacttest' volatile;
begin;
update xacttest set a = max_xacttest() + 10 where a > 0;
select * from xacttest;
rollback;
-- Now the same test with plpgsql (since it depends on SPI which is different)
create or replace function max_xacttest() returns smallint language plpgsql as
'begin return max(a) from xacttest; end' stable;
begin;
update xacttest set a = max_xacttest() + 10 where a > 0;
select * from xacttest;
rollback;
create or replace function max_xacttest() returns smallint language plpgsql as
'begin return max(a) from xacttest; end' volatile;
begin;
update xacttest set a = max_xacttest() + 10 where a > 0;
select * from xacttest;
rollback;
-- test case for problems with dropping an open relation during abort
BEGIN;
savepoint x;
CREATE TABLE koju (a INT UNIQUE);
INSERT INTO koju VALUES (1);
INSERT INTO koju VALUES (1);
rollback to x;
CREATE TABLE koju (a INT UNIQUE);
INSERT INTO koju VALUES (1);
INSERT INTO koju VALUES (1);
ROLLBACK;
DROP TABLE foo;
DROP TABLE baz;
DROP TABLE barbaz;
-- test case for problems with revalidating an open relation during abort
create function inverse(int) returns float8 as
$$
begin
analyze revalidate_bug;
return 1::float8/$1;
exception
when division_by_zero then return 0;
end$$ language plpgsql volatile;
create table revalidate_bug (c float8 unique);
insert into revalidate_bug values (1);
insert into revalidate_bug values (inverse(0));
drop table revalidate_bug;
drop function inverse(int);
-- verify that cursors created during an aborted subtransaction are
-- closed, but that we do not rollback the effect of any FETCHs
-- performed in the aborted subtransaction
begin;
savepoint x;
create table abc (a int);
insert into abc values (5);
insert into abc values (10);
declare foo cursor for select * from abc;
fetch from foo;
rollback to x;
-- should fail
fetch from foo;
commit;
begin;
create table abc (a int);
insert into abc values (5);
insert into abc values (10);
insert into abc values (15);
declare foo cursor for select * from abc;
fetch from foo;
savepoint x;
fetch from foo;
rollback to x;
fetch from foo;
abort;
-- Test for proper cleanup after a failure in a cursor portal
-- that was created in an outer subtransaction
CREATE FUNCTION invert(x float8) RETURNS float8 LANGUAGE plpgsql AS
$$ begin return 1/x; end $$;
CREATE FUNCTION create_temp_tab() RETURNS text
LANGUAGE plpgsql AS $$
BEGIN
CREATE TEMP TABLE new_table (f1 float8);
-- case of interest is that we fail while holding an open
-- relcache reference to new_table
INSERT INTO new_table SELECT invert(0.0);
RETURN 'foo';
END $$;
BEGIN;
DECLARE ok CURSOR FOR SELECT * FROM int8_tbl;
DECLARE ctt CURSOR FOR SELECT create_temp_tab();
FETCH ok;
SAVEPOINT s1;
FETCH ok; -- should work
FETCH ctt; -- error occurs here
ROLLBACK TO s1;
FETCH ok; -- should work
FETCH ctt; -- must be rejected
COMMIT;
DROP FUNCTION create_temp_tab();
DROP FUNCTION invert(x float8);
-- Test assorted behaviors around the implicit transaction block created
-- when multiple SQL commands are sent in a single Query message. These
-- tests rely on the fact that psql will not break SQL commands apart at a
-- backslash-quoted semicolon, but will send them as one Query.
create temp table i_table (f1 int);
-- psql will show only the last result in a multi-statement Query
SELECT 1\; SELECT 2\; SELECT 3;
-- this implicitly commits:
insert into i_table values(1)\; select * from i_table;
-- 1/0 error will cause rolling back the whole implicit transaction
insert into i_table values(2)\; select * from i_table\; select 1/0;
select * from i_table;
rollback; -- we are not in a transaction at this point
-- can use regular begin/commit/rollback within a single Query
begin\; insert into i_table values(3)\; commit;
rollback; -- we are not in a transaction at this point
begin\; insert into i_table values(4)\; rollback;
rollback; -- we are not in a transaction at this point
-- begin converts implicit transaction into a regular one that
-- can extend past the end of the Query
select 1\; begin\; insert into i_table values(5);
commit;
select 1\; begin\; insert into i_table values(6);
rollback;
-- commit in implicit-transaction state commits but issues a warning.
insert into i_table values(7)\; commit\; insert into i_table values(8)\; select 1/0;
-- similarly, rollback aborts but issues a warning.
insert into i_table values(9)\; rollback\; select 2;
select * from i_table;
rollback; -- we are not in a transaction at this point
-- implicit transaction block is still a transaction block, for e.g. VACUUM
SELECT 1\; VACUUM;
SELECT 1\; COMMIT\; VACUUM;
-- we disallow savepoint-related commands in implicit-transaction state
SELECT 1\; SAVEPOINT sp;
SELECT 1\; COMMIT\; SAVEPOINT sp;
ROLLBACK TO SAVEPOINT sp\; SELECT 2;
SELECT 2\; RELEASE SAVEPOINT sp\; SELECT 3;
-- but this is OK, because the BEGIN converts it to a regular xact
SELECT 1\; BEGIN\; SAVEPOINT sp\; ROLLBACK TO SAVEPOINT sp\; COMMIT;
-- Test for successful cleanup of an aborted transaction at session exit.
-- THIS MUST BE THE LAST TEST IN THIS FILE.
begin;
select 1/0;
rollback to X;
-- DO NOT ADD ANYTHING HERE.
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