PL/pgSQL: Add support for SET TRANSACTION

A normal SQL command run inside PL/pgSQL acquires a snapshot, but SET
TRANSACTION does not work anymore if a snapshot is set.  So we have to
handle this separately.

Reviewed-by: Alexander Korotkov <[email protected]>
Reviewed-by: Tomas Vondra <[email protected]>

diff --git a/src/pl/plpgsql/src/expected/plpgsql_transaction.out b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
index b7f77101c3df456fb2d494d4a14b3bdb142b0346..2d0e3fa85ede2e6deb983d33c68cdf39eb03db11 100644 (file)
--- a/src/pl/plpgsql/src/expected/plpgsql_transaction.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
@@ -389,6 +389,35 @@ SELECT * FROM test3;
  1
 (1 row)
 
+-- SET TRANSACTION
+DO LANGUAGE plpgsql $$
+BEGIN
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+    RESET TRANSACTION ISOLATION LEVEL;
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+END;
+$$;
+INFO:  read committed
+INFO:  repeatable read
+INFO:  read committed
+-- error case
+DO LANGUAGE plpgsql $$
+BEGIN
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+END;
+$$;
+ERROR:  SET TRANSACTION ISOLATION LEVEL must be called before any query
+CONTEXT:  SQL statement "SET TRANSACTION ISOLATION LEVEL REPEATABLE READ"
+PL/pgSQL function inline_code_block line 3 at SET
 DROP TABLE test1;
 DROP TABLE test2;
 DROP TABLE test3;

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 255bdbf2c8e597d64e8a37150edb99bdb57175be..4b6f51ac98d98ba37506644eb8a7b3b39262e4ce 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -305,6 +305,8 @@ static int exec_stmt_commit(PLpgSQL_execstate *estate,
                                 PLpgSQL_stmt_commit *stmt);
 static int exec_stmt_rollback(PLpgSQL_execstate *estate,
                                   PLpgSQL_stmt_rollback *stmt);
+static int exec_stmt_set(PLpgSQL_execstate *estate,
+                                  PLpgSQL_stmt_set *stmt);
 
 static void plpgsql_estate_setup(PLpgSQL_execstate *estate,
                                         PLpgSQL_function *func,
@@ -2005,6 +2007,10 @@ exec_stmt(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
                        rc = exec_stmt_rollback(estate, (PLpgSQL_stmt_rollback *) stmt);
                        break;
 
+               case PLPGSQL_STMT_SET:
+                       rc = exec_stmt_set(estate, (PLpgSQL_stmt_set *) stmt);
+                       break;
+
                default:
                        estate->err_stmt = save_estmt;
                        elog(ERROR, "unrecognized cmd_type: %d", stmt->cmd_type);
@@ -4732,6 +4738,35 @@ exec_stmt_rollback(PLpgSQL_execstate *estate, PLpgSQL_stmt_rollback *stmt)
        return PLPGSQL_RC_OK;
 }
 
+/*
+ * exec_stmt_set
+ *
+ * Execute SET/RESET statement.
+ *
+ * We just parse and execute the statement normally, but we have to do it
+ * without setting a snapshot, for things like SET TRANSACTION.
+ */
+static int
+exec_stmt_set(PLpgSQL_execstate *estate, PLpgSQL_stmt_set *stmt)
+{
+       PLpgSQL_expr *expr = stmt->expr;
+       int                     rc;
+
+       if (expr->plan == NULL)
+       {
+               exec_prepare_plan(estate, expr, 0, true);
+               expr->plan->no_snapshots = true;
+       }
+
+       rc = SPI_execute_plan(expr->plan, NULL, NULL, estate->readonly_func, 0);
+
+       if (rc != SPI_OK_UTILITY)
+               elog(ERROR, "SPI_execute_plan failed executing query \"%s\": %s",
+                        expr->query, SPI_result_code_string(rc));
+
+       return PLPGSQL_RC_OK;
+}
+
 /* ----------
  * exec_assign_expr                    Put an expression's result into a variable.
  * ----------

diff --git a/src/pl/plpgsql/src/pl_funcs.c b/src/pl/plpgsql/src/pl_funcs.c
index fc96fb5f4d10a7430e295ebdd813fa70d3370bc3..b93f866223335f365ec8c038509383b09cea1adf 100644 (file)
--- a/src/pl/plpgsql/src/pl_funcs.c
+++ b/src/pl/plpgsql/src/pl_funcs.c
@@ -290,6 +290,8 @@ plpgsql_stmt_typename(PLpgSQL_stmt *stmt)
                        return "COMMIT";
                case PLPGSQL_STMT_ROLLBACK:
                        return "ROLLBACK";
+               case PLPGSQL_STMT_SET:
+                       return "SET";
        }
 
        return "unknown";
@@ -372,6 +374,7 @@ static void free_perform(PLpgSQL_stmt_perform *stmt);
 static void free_call(PLpgSQL_stmt_call *stmt);
 static void free_commit(PLpgSQL_stmt_commit *stmt);
 static void free_rollback(PLpgSQL_stmt_rollback *stmt);
+static void free_set(PLpgSQL_stmt_set *stmt);
 static void free_expr(PLpgSQL_expr *expr);
 
 
@@ -461,6 +464,9 @@ free_stmt(PLpgSQL_stmt *stmt)
                case PLPGSQL_STMT_ROLLBACK:
                        free_rollback((PLpgSQL_stmt_rollback *) stmt);
                        break;
+               case PLPGSQL_STMT_SET:
+                       free_set((PLpgSQL_stmt_set *) stmt);
+                       break;
                default:
                        elog(ERROR, "unrecognized cmd_type: %d", stmt->cmd_type);
                        break;
@@ -624,6 +630,12 @@ free_rollback(PLpgSQL_stmt_rollback *stmt)
 {
 }
 
+static void
+free_set(PLpgSQL_stmt_set *stmt)
+{
+       free_expr(stmt->expr);
+}
+
 static void
 free_exit(PLpgSQL_stmt_exit *stmt)
 {
@@ -820,6 +832,7 @@ static void dump_perform(PLpgSQL_stmt_perform *stmt);
 static void dump_call(PLpgSQL_stmt_call *stmt);
 static void dump_commit(PLpgSQL_stmt_commit *stmt);
 static void dump_rollback(PLpgSQL_stmt_rollback *stmt);
+static void dump_set(PLpgSQL_stmt_set *stmt);
 static void dump_expr(PLpgSQL_expr *expr);
 
 
@@ -919,6 +932,9 @@ dump_stmt(PLpgSQL_stmt *stmt)
                case PLPGSQL_STMT_ROLLBACK:
                        dump_rollback((PLpgSQL_stmt_rollback *) stmt);
                        break;
+               case PLPGSQL_STMT_SET:
+                       dump_set((PLpgSQL_stmt_set *) stmt);
+                       break;
                default:
                        elog(ERROR, "unrecognized cmd_type: %d", stmt->cmd_type);
                        break;
@@ -1314,6 +1330,13 @@ dump_rollback(PLpgSQL_stmt_rollback *stmt)
        printf("ROLLBACK\n");
 }
 
+static void
+dump_set(PLpgSQL_stmt_set *stmt)
+{
+       dump_ind();
+       printf("%s\n", stmt->expr->query);
+}
+
 static void
 dump_exit(PLpgSQL_stmt_exit *stmt)
 {

diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index d928efa13eabdd54bf58cc92a8a5138a6f79a33b..f9ba19cbdf0f7204d16f52b2cec4016e5508953b 100644 (file)
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -199,7 +199,7 @@ static      void                    check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %type <stmt>   stmt_return stmt_raise stmt_assert stmt_execsql
 %type <stmt>   stmt_dynexecute stmt_for stmt_perform stmt_call stmt_getdiag
 %type <stmt>   stmt_open stmt_fetch stmt_move stmt_close stmt_null
-%type <stmt>   stmt_commit stmt_rollback
+%type <stmt>   stmt_commit stmt_rollback stmt_set
 %type <stmt>   stmt_case stmt_foreach_a
 
 %type <list>   proc_exceptions
@@ -327,6 +327,7 @@ static      void                    check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>       K_QUERY
 %token <keyword>       K_RAISE
 %token <keyword>       K_RELATIVE
+%token <keyword>       K_RESET
 %token <keyword>       K_RESULT_OID
 %token <keyword>       K_RETURN
 %token <keyword>       K_RETURNED_SQLSTATE
@@ -337,6 +338,7 @@ static      void                    check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>       K_SCHEMA
 %token <keyword>       K_SCHEMA_NAME
 %token <keyword>       K_SCROLL
+%token <keyword>       K_SET
 %token <keyword>       K_SLICE
 %token <keyword>       K_SQLSTATE
 %token <keyword>       K_STACKED
@@ -893,6 +895,8 @@ proc_stmt           : pl_block ';'
                                                { $$ = $1; }
                                | stmt_rollback
                                                { $$ = $1; }
+                               | stmt_set
+                                               { $$ = $1; }
                                ;
 
 stmt_perform   : K_PERFORM expr_until_semi
@@ -2206,6 +2210,30 @@ stmt_rollback    : K_ROLLBACK ';'
                                        }
                                ;
 
+stmt_set       : K_SET
+                                       {
+                                               PLpgSQL_stmt_set *new;
+
+                                               new = palloc0(sizeof(PLpgSQL_stmt_set));
+                                               new->cmd_type = PLPGSQL_STMT_SET;
+                                               new->lineno = plpgsql_location_to_lineno(@1);
+                                               new->expr = read_sql_stmt("SET ");
+
+                                               $$ = (PLpgSQL_stmt *)new;
+                                       }
+                       | K_RESET
+                                       {
+                                               PLpgSQL_stmt_set *new;
+
+                                               new = palloc0(sizeof(PLpgSQL_stmt_set));
+                                               new->cmd_type = PLPGSQL_STMT_SET;
+                                               new->lineno = plpgsql_location_to_lineno(@1);
+                                               new->expr = read_sql_stmt("RESET ");
+
+                                               $$ = (PLpgSQL_stmt *)new;
+                                       }
+                       ;
+
 
 cursor_variable        : T_DATUM
                                        {
@@ -2494,6 +2522,7 @@ unreserved_keyword        :
                                | K_QUERY
                                | K_RAISE
                                | K_RELATIVE
+                               | K_RESET
                                | K_RESULT_OID
                                | K_RETURN
                                | K_RETURNED_SQLSTATE
@@ -2504,6 +2533,7 @@ unreserved_keyword        :
                                | K_SCHEMA
                                | K_SCHEMA_NAME
                                | K_SCROLL
+                               | K_SET
                                | K_SLICE
                                | K_SQLSTATE
                                | K_STACKED

diff --git a/src/pl/plpgsql/src/pl_scanner.c b/src/pl/plpgsql/src/pl_scanner.c
index 81b5bd1fe03a911d09894b311a080387ef812b2f..256fc0a243b77de28b8b8be37d913184ad9a74b0 100644 (file)
--- a/src/pl/plpgsql/src/pl_scanner.c
+++ b/src/pl/plpgsql/src/pl_scanner.c
@@ -158,6 +158,7 @@ static const ScanKeyword unreserved_keywords[] = {
        PG_KEYWORD("query", K_QUERY, UNRESERVED_KEYWORD)
        PG_KEYWORD("raise", K_RAISE, UNRESERVED_KEYWORD)
        PG_KEYWORD("relative", K_RELATIVE, UNRESERVED_KEYWORD)
+       PG_KEYWORD("reset", K_RESET, UNRESERVED_KEYWORD)
        PG_KEYWORD("result_oid", K_RESULT_OID, UNRESERVED_KEYWORD)
        PG_KEYWORD("return", K_RETURN, UNRESERVED_KEYWORD)
        PG_KEYWORD("returned_sqlstate", K_RETURNED_SQLSTATE, UNRESERVED_KEYWORD)
@@ -168,6 +169,7 @@ static const ScanKeyword unreserved_keywords[] = {
        PG_KEYWORD("schema", K_SCHEMA, UNRESERVED_KEYWORD)
        PG_KEYWORD("schema_name", K_SCHEMA_NAME, UNRESERVED_KEYWORD)
        PG_KEYWORD("scroll", K_SCROLL, UNRESERVED_KEYWORD)
+       PG_KEYWORD("set", K_SET, UNRESERVED_KEYWORD)
        PG_KEYWORD("slice", K_SLICE, UNRESERVED_KEYWORD)
        PG_KEYWORD("sqlstate", K_SQLSTATE, UNRESERVED_KEYWORD)
        PG_KEYWORD("stacked", K_STACKED, UNRESERVED_KEYWORD)

diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 3f617201d674702eb76c669d31919001759d9a3d..8d30180d4243f2b4277eab0a1c5891731b7918eb 100644 (file)
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -127,7 +127,8 @@ typedef enum PLpgSQL_stmt_type
        PLPGSQL_STMT_PERFORM,
        PLPGSQL_STMT_CALL,
        PLPGSQL_STMT_COMMIT,
-       PLPGSQL_STMT_ROLLBACK
+       PLPGSQL_STMT_ROLLBACK,
+       PLPGSQL_STMT_SET
 } PLpgSQL_stmt_type;
 
 /*
@@ -539,6 +540,16 @@ typedef struct PLpgSQL_stmt_rollback
        int                     lineno;
 } PLpgSQL_stmt_rollback;
 
+/*
+ * SET statement
+ */
+typedef struct PLpgSQL_stmt_set
+{
+       PLpgSQL_stmt_type cmd_type;
+       int                     lineno;
+       PLpgSQL_expr *expr;
+} PLpgSQL_stmt_set;
+
 /*
  * GET DIAGNOSTICS item
  */

diff --git a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
index b7b6f81128a2ed7665f723478ba3812cc93d2485..373d89864a233e207863a14181362f2a8c784e9c 100644 (file)
--- a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
@@ -317,6 +317,31 @@ $$;
 SELECT * FROM test3;
 
 
+-- SET TRANSACTION
+DO LANGUAGE plpgsql $$
+BEGIN
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+    RESET TRANSACTION ISOLATION LEVEL;
+    PERFORM 1;
+    RAISE INFO '%', current_setting('transaction_isolation');
+    COMMIT;
+END;
+$$;
+
+-- error case
+DO LANGUAGE plpgsql $$
+BEGIN
+    SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;
+END;
+$$;
+
 DROP TABLE test1;
 DROP TABLE test2;
 DROP TABLE test3;