Transaction chaining

Add command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN, which
start new transactions with the same transaction characteristics as the
just finished one, per SQL standard.

Support for transaction chaining in PL/pgSQL is also added.  This
functionality is especially useful when running COMMIT in a loop in
PL/pgSQL.

Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/28536681-324b-10dc-ade8-ab46f7645a5a@2ndquadrant.com

2 files changed, 254 insertions, 0 deletions

diff --git a/src/test/regress/expected/transactions.out b/src/test/regress/expected/transactions.out
index 69e176c5259..1b316cc9b8c 100644
--- a/src/test/regress/expected/transactions.out
+++ b/src/test/regress/expected/transactions.out
@@ -659,6 +659,197 @@ ERROR:  portal "ctt" cannot be run
 COMMIT;
 DROP FUNCTION create_temp_tab();
 DROP FUNCTION invert(x float8);
+-- Tests for AND CHAIN
+CREATE TABLE abc (a int);
+-- set nondefault value so we have something to override below
+SET default_transaction_read_only = on;
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, READ WRITE, DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (1);
+INSERT INTO abc VALUES (2);
+COMMIT AND CHAIN;  -- TBLOCK_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for type integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+INSERT INTO abc VALUES (3);  -- check it's really aborted
+ERROR:  current transaction is aborted, commands ignored until end of transaction block
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (4);
+COMMIT;
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, READ WRITE, DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+SAVEPOINT x;
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for type integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (5);
+COMMIT;
+-- different mix of options just for fun
+START TRANSACTION ISOLATION LEVEL SERIALIZABLE, READ WRITE, NOT DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ serializable
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ off
+(1 row)
+
+INSERT INTO abc VALUES (6);
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ serializable
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ off
+(1 row)
+
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for type integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ serializable
+(1 row)
+
+SHOW transaction_read_only;
+ transaction_read_only 
+-----------------------
+ off
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ off
+(1 row)
+
+ROLLBACK;
+SELECT * FROM abc ORDER BY 1;
+ a 
+---
+ 1
+ 2
+ 4
+ 5
+(4 rows)
+
+RESET default_transaction_read_only;
+DROP TABLE abc;
 -- 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
diff --git a/src/test/regress/sql/transactions.sql b/src/test/regress/sql/transactions.sql
index 2e3739fd6c4..812e40a1a3a 100644
--- a/src/test/regress/sql/transactions.sql
+++ b/src/test/regress/sql/transactions.sql
@@ -419,6 +419,69 @@ DROP FUNCTION create_temp_tab();
 DROP FUNCTION invert(x float8);
 
 
+-- Tests for AND CHAIN
+
+CREATE TABLE abc (a int);
+
+-- set nondefault value so we have something to override below
+SET default_transaction_read_only = on;
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, READ WRITE, DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (1);
+INSERT INTO abc VALUES (2);
+COMMIT AND CHAIN;  -- TBLOCK_END
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES ('error');
+INSERT INTO abc VALUES (3);  -- check it's really aborted
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (4);
+COMMIT;
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, READ WRITE, DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+SAVEPOINT x;
+INSERT INTO abc VALUES ('error');
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (5);
+COMMIT;
+
+-- different mix of options just for fun
+START TRANSACTION ISOLATION LEVEL SERIALIZABLE, READ WRITE, NOT DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (6);
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES ('error');
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+SHOW transaction_read_only;
+SHOW transaction_deferrable;
+ROLLBACK;
+
+SELECT * FROM abc ORDER BY 1;
+
+RESET default_transaction_read_only;
+
+DROP TABLE abc;
+
+
 -- 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