<title>Transaction Management</title>
<para>
- In procedures invoked by the <command>CALL</command> command from the top
- level as well as in anonymous code blocks (<command>DO</command> command)
- called from the top level, it is possible to end transactions using the
+ In procedures invoked by the <command>CALL</command> command
+ as well as in anonymous code blocks (<command>DO</command> command),
+ it is possible to end transactions using the
commands <command>COMMIT</command> and <command>ROLLBACK</command>. A new
transaction is started automatically after a transaction is ended using
these commands, so there is no separate <command>START
</programlisting>
</para>
+ <para>
+ Transaction control is only possible in <command>CALL</command> or
+ <command>DO</command> invocations from the top level or nested
+ <command>CALL</command> or <command>DO</command> invocations without any
+ other intervening command. For example, if the call stack is
+ <command>CALL proc1()</command> → <command>CALL proc2()</command>
+ → <command>CALL proc3()</command>, then the second and third
+ procedures can perform transaction control actions. But if the call stack
+ is <command>CALL proc1()</command> → <command>SELECT
+ func2()</command> → <command>CALL proc3()</command>, then the last
+ procedure cannot do transaction control, because of the
+ <command>SELECT</command> in between.
+ </para>
+
<para>
A transaction cannot be ended inside a loop over a query result, nor
inside a block with exception handlers.
*
* In the first two cases, we can just push the snap onto the stack once
* for the whole plan list.
+ *
+ * But if the plan has no_snapshots set to true, then don't manage
+ * snapshots at all. The caller should then take care of that.
*/
- if (snapshot != InvalidSnapshot)
+ if (snapshot != InvalidSnapshot && !plan->no_snapshots)
{
if (read_only)
{
* In the default non-read-only case, get a new snapshot, replacing
* any that we pushed in a previous cycle.
*/
- if (snapshot == InvalidSnapshot && !read_only)
+ if (snapshot == InvalidSnapshot && !read_only && !plan->no_snapshots)
{
if (pushed_active_snap)
PopActiveSnapshot();
* If not read-only mode, advance the command counter before each
* command and update the snapshot.
*/
- if (!read_only)
+ if (!read_only && !plan->no_snapshots)
{
CommandCounterIncrement();
UpdateActiveSnapshotCommandId();
else
{
char completionTag[COMPLETION_TAG_BUFSIZE];
+ ProcessUtilityContext context;
+
+ /*
+ * If the SPI context is atomic, or we are asked to manage
+ * snapshots, then we are in an atomic execution context.
+ * Conversely, to propagate a nonatomic execution context, the
+ * caller must be in a nonatomic SPI context and manage
+ * snapshots itself.
+ */
+ if (_SPI_current->atomic || !plan->no_snapshots)
+ context = PROCESS_UTILITY_QUERY;
+ else
+ context = PROCESS_UTILITY_QUERY_NONATOMIC;
ProcessUtility(stmt,
plansource->query_string,
- PROCESS_UTILITY_QUERY,
+ context,
paramLI,
_SPI_current->queryEnv,
dest,
oldcxt = MemoryContextSwitchTo(plancxt);
/* Copy the SPI_plan struct and subsidiary data into the new context */
- newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
+ newplan = (SPIPlanPtr) palloc0(sizeof(_SPI_plan));
newplan->magic = _SPI_PLAN_MAGIC;
- newplan->saved = false;
- newplan->oneshot = false;
- newplan->plancache_list = NIL;
newplan->plancxt = plancxt;
newplan->cursor_options = plan->cursor_options;
newplan->nargs = plan->nargs;
oldcxt = MemoryContextSwitchTo(plancxt);
/* Copy the SPI plan into its own context */
- newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
+ newplan = (SPIPlanPtr) palloc0(sizeof(_SPI_plan));
newplan->magic = _SPI_PLAN_MAGIC;
- newplan->saved = false;
- newplan->oneshot = false;
- newplan->plancache_list = NIL;
newplan->plancxt = plancxt;
newplan->cursor_options = plan->cursor_options;
newplan->nargs = plan->nargs;
{
Node *parsetree = pstmt->utilityStmt;
bool isTopLevel = (context == PROCESS_UTILITY_TOPLEVEL);
- bool isAtomicContext = (context != PROCESS_UTILITY_TOPLEVEL || IsTransactionBlock());
+ bool isAtomicContext = (!(context == PROCESS_UTILITY_TOPLEVEL || context == PROCESS_UTILITY_QUERY_NONATOMIC) || IsTransactionBlock());
ParseState *pstate;
check_xact_readonly(parsetree);
int magic; /* should equal _SPI_PLAN_MAGIC */
bool saved; /* saved or unsaved plan? */
bool oneshot; /* one-shot plan? */
+ bool no_snapshots; /* let the caller handle the snapshots */
List *plancache_list; /* one CachedPlanSource per parsetree */
MemoryContext plancxt; /* Context containing _SPI_plan and data */
int cursor_options; /* Cursor options used for planning */
{
PROCESS_UTILITY_TOPLEVEL, /* toplevel interactive command */
PROCESS_UTILITY_QUERY, /* a complete query, but not toplevel */
+ PROCESS_UTILITY_QUERY_NONATOMIC, /* a complete query, nonatomic execution context */
PROCESS_UTILITY_SUBCOMMAND /* a portion of a query */
} ProcessUtilityContext;
CREATE TABLE test1 (a int, b text);
-CREATE PROCEDURE transaction_test1()
+CREATE PROCEDURE transaction_test1(x int, y text)
LANGUAGE plpgsql
AS $$
BEGIN
- FOR i IN 0..9 LOOP
- INSERT INTO test1 (a) VALUES (i);
+ FOR i IN 0..x LOOP
+ INSERT INTO test1 (a, b) VALUES (i, y);
IF i % 2 = 0 THEN
COMMIT;
ELSE
END LOOP;
END
$$;
-CALL transaction_test1();
+CALL transaction_test1(9, 'foo');
SELECT * FROM test1;
- a | b
----+---
- 0 |
- 2 |
- 4 |
- 6 |
- 8 |
+ a | b
+---+-----
+ 0 | foo
+ 2 | foo
+ 4 | foo
+ 6 | foo
+ 8 | foo
(5 rows)
TRUNCATE test1;
-- transaction commands not allowed when called in transaction block
START TRANSACTION;
-CALL transaction_test1();
+CALL transaction_test1(9, 'error');
ERROR: invalid transaction termination
-CONTEXT: PL/pgSQL function transaction_test1() line 6 at COMMIT
+CONTEXT: PL/pgSQL function transaction_test1(integer,text) line 6 at COMMIT
COMMIT;
START TRANSACTION;
DO LANGUAGE plpgsql $$ BEGIN COMMIT; END $$;
LANGUAGE plpgsql
AS $$
BEGIN
- CALL transaction_test1();
+ CALL transaction_test1(9, 'error');
RETURN 1;
END;
$$;
SELECT transaction_test3();
ERROR: invalid transaction termination
-CONTEXT: PL/pgSQL function transaction_test1() line 6 at COMMIT
-SQL statement "CALL transaction_test1()"
+CONTEXT: PL/pgSQL function transaction_test1(integer,text) line 6 at COMMIT
+SQL statement "CALL transaction_test1(9, 'error')"
PL/pgSQL function transaction_test3() line 3 at CALL
SELECT * FROM test1;
a | b
CALL transaction_test5();
ERROR: invalid transaction termination
CONTEXT: PL/pgSQL function transaction_test5() line 3 at COMMIT
+TRUNCATE test1;
+-- nested procedure calls
+CREATE PROCEDURE transaction_test6(c text)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ CALL transaction_test1(9, c);
+END;
+$$;
+CALL transaction_test6('bar');
+SELECT * FROM test1;
+ a | b
+---+-----
+ 0 | bar
+ 2 | bar
+ 4 | bar
+ 6 | bar
+ 8 | bar
+(5 rows)
+
+TRUNCATE test1;
+CREATE PROCEDURE transaction_test7()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ DO 'BEGIN CALL transaction_test1(9, $x$baz$x$); END;';
+END;
+$$;
+CALL transaction_test7();
+SELECT * FROM test1;
+ a | b
+---+-----
+ 0 | baz
+ 2 | baz
+ 4 | baz
+ 6 | baz
+ 8 | baz
+(5 rows)
+
+CREATE PROCEDURE transaction_test8()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ EXECUTE 'CALL transaction_test1(10, $x$baz$x$)';
+END;
+$$;
+CALL transaction_test8();
+ERROR: invalid transaction termination
+CONTEXT: PL/pgSQL function transaction_test1(integer,text) line 6 at COMMIT
+SQL statement "CALL transaction_test1(10, $x$baz$x$)"
+PL/pgSQL function transaction_test8() line 3 at EXECUTE
-- commit inside cursor loop
CREATE TABLE test2 (x int);
INSERT INTO test2 VALUES (0), (1), (2), (3), (4);
#include "access/tupconvert.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
+#include "commands/defrem.h"
#include "executor/execExpr.h"
#include "executor/spi.h"
#include "executor/spi_priv.h"
#include "parser/scansup.h"
#include "storage/proc.h"
#include "tcop/tcopprot.h"
+#include "tcop/utility.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/datum.h"
static void exec_eval_cleanup(PLpgSQL_execstate *estate);
static void exec_prepare_plan(PLpgSQL_execstate *estate,
- PLpgSQL_expr *expr, int cursorOptions);
+ PLpgSQL_expr *expr, int cursorOptions,
+ bool keepplan);
static void exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr);
static void exec_save_simple_expr(PLpgSQL_expr *expr, CachedPlan *cplan);
static void exec_check_rw_parameter(PLpgSQL_expr *expr, int target_dno);
*/
Datum
plpgsql_exec_function(PLpgSQL_function *func, FunctionCallInfo fcinfo,
- EState *simple_eval_estate)
+ EState *simple_eval_estate, bool atomic)
{
PLpgSQL_execstate estate;
ErrorContextCallback plerrcontext;
*/
plpgsql_estate_setup(&estate, func, (ReturnSetInfo *) fcinfo->resultinfo,
simple_eval_estate);
+ estate.atomic = atomic;
/*
* Setup error traceback support for ereport()
{
PLpgSQL_expr *expr = stmt->expr;
ParamListInfo paramLI;
+ LocalTransactionId before_lxid;
+ LocalTransactionId after_lxid;
int rc;
if (expr->plan == NULL)
- exec_prepare_plan(estate, expr, 0);
+ {
+ /*
+ * Don't save the plan if not in atomic context. Otherwise,
+ * transaction ends would cause warnings about plan leaks.
+ */
+ exec_prepare_plan(estate, expr, 0, estate->atomic);
+
+ /*
+ * The procedure call could end transactions, which would upset the
+ * snapshot management in SPI_execute*, so don't let it do it.
+ */
+ expr->plan->no_snapshots = true;
+ }
paramLI = setup_param_list(estate, expr);
+ before_lxid = MyProc->lxid;
+
rc = SPI_execute_plan_with_paramlist(expr->plan, paramLI,
estate->readonly_func, 0);
+ after_lxid = MyProc->lxid;
+
if (rc < 0)
elog(ERROR, "SPI_execute_plan_with_paramlist failed executing query \"%s\": %s",
expr->query, SPI_result_code_string(rc));
+ /*
+ * If we are in a new transaction after the call, we need to reset some
+ * internal state.
+ */
+ if (before_lxid != after_lxid)
+ {
+ estate->simple_eval_estate = NULL;
+ plpgsql_create_econtext(estate);
+ }
+
if (SPI_processed == 1)
{
SPITupleTable *tuptab = SPI_tuptable;
Assert(query);
if (query->plan == NULL)
- exec_prepare_plan(estate, query, curvar->cursor_options);
+ exec_prepare_plan(estate, query, curvar->cursor_options, true);
/*
* Set up ParamListInfo for this query
estate->retisset = func->fn_retset;
estate->readonly_func = func->fn_readonly;
+ estate->atomic = true;
estate->exitlabel = NULL;
estate->cur_error = NULL;
*/
static void
exec_prepare_plan(PLpgSQL_execstate *estate,
- PLpgSQL_expr *expr, int cursorOptions)
+ PLpgSQL_expr *expr, int cursorOptions,
+ bool keepplan)
{
SPIPlanPtr plan;
expr->query, SPI_result_code_string(SPI_result));
}
}
- SPI_keepplan(plan);
+ if (keepplan)
+ SPI_keepplan(plan);
expr->plan = plan;
/* Check to see if it's a simple expression */
{
ListCell *l;
- exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK);
+ exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK, true);
stmt->mod_stmt = false;
foreach(l, SPI_plan_get_plan_sources(expr->plan))
{
*/
query = stmt->query;
if (query->plan == NULL)
- exec_prepare_plan(estate, query, stmt->cursor_options);
+ exec_prepare_plan(estate, query, stmt->cursor_options, true);
}
else if (stmt->dynquery != NULL)
{
query = curvar->cursor_explicit_expr;
if (query->plan == NULL)
- exec_prepare_plan(estate, query, curvar->cursor_options);
+ exec_prepare_plan(estate, query, curvar->cursor_options, true);
}
/*
*/
if (expr->plan == NULL)
{
- exec_prepare_plan(estate, expr, 0);
+ exec_prepare_plan(estate, expr, 0, true);
if (target->dtype == PLPGSQL_DTYPE_VAR)
exec_check_rw_parameter(expr, target->dno);
}
* If first time through, create a plan for this expression.
*/
if (expr->plan == NULL)
- exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK);
+ exec_prepare_plan(estate, expr, CURSOR_OPT_PARALLEL_OK, true);
/*
* If this is a simple expression, bypass SPI and use the executor
*/
if (expr->plan == NULL)
exec_prepare_plan(estate, expr,
- portalP == NULL ? CURSOR_OPT_PARALLEL_OK : 0);
+ portalP == NULL ? CURSOR_OPT_PARALLEL_OK : 0, true);
/*
* Set up ParamListInfo to pass to executor
{
MemoryContext oldcontext;
- Assert(shared_simple_eval_estate == NULL);
- oldcontext = MemoryContextSwitchTo(TopTransactionContext);
- shared_simple_eval_estate = CreateExecutorState();
+ if (shared_simple_eval_estate == NULL)
+ {
+ oldcontext = MemoryContextSwitchTo(TopTransactionContext);
+ shared_simple_eval_estate = CreateExecutorState();
+ MemoryContextSwitchTo(oldcontext);
+ }
estate->simple_eval_estate = shared_simple_eval_estate;
- MemoryContextSwitchTo(oldcontext);
}
/*
case PLPGSQL_STMT_PERFORM:
return "PERFORM";
case PLPGSQL_STMT_CALL:
- return "CALL";
+ return ((PLpgSQL_stmt_call *) stmt)->is_call ? "CALL" : "DO";
case PLPGSQL_STMT_COMMIT:
return "COMMIT";
case PLPGSQL_STMT_ROLLBACK:
dump_call(PLpgSQL_stmt_call *stmt)
{
dump_ind();
- printf("CALL expr = ");
+ printf("%s expr = ", stmt->is_call ? "CALL" : "DO");
dump_expr(stmt->expr);
printf("\n");
}
%token <keyword> K_DEFAULT
%token <keyword> K_DETAIL
%token <keyword> K_DIAGNOSTICS
+%token <keyword> K_DO
%token <keyword> K_DUMP
%token <keyword> K_ELSE
%token <keyword> K_ELSIF
new->cmd_type = PLPGSQL_STMT_CALL;
new->lineno = plpgsql_location_to_lineno(@1);
new->expr = read_sql_stmt("CALL ");
+ new->is_call = true;
$$ = (PLpgSQL_stmt *)new;
+
+ }
+ | K_DO
+ {
+ /* use the same structures as for CALL, for simplicity */
+ PLpgSQL_stmt_call *new;
+
+ new = palloc0(sizeof(PLpgSQL_stmt_call));
+ new->cmd_type = PLPGSQL_STMT_CALL;
+ new->lineno = plpgsql_location_to_lineno(@1);
+ new->expr = read_sql_stmt("DO ");
+ new->is_call = false;
+
+ $$ = (PLpgSQL_stmt *)new;
+
}
;
| K_DEFAULT
| K_DETAIL
| K_DIAGNOSTICS
+ | K_DO
| K_DUMP
| K_ELSIF
| K_ERRCODE
retval = (Datum) 0;
}
else
- retval = plpgsql_exec_function(func, fcinfo, NULL);
+ retval = plpgsql_exec_function(func, fcinfo, NULL, !nonatomic);
}
PG_CATCH();
{
/* And run the function */
PG_TRY();
{
- retval = plpgsql_exec_function(func, &fake_fcinfo, simple_eval_estate);
+ retval = plpgsql_exec_function(func, &fake_fcinfo, simple_eval_estate, codeblock->atomic);
}
PG_CATCH();
{
PG_KEYWORD("default", K_DEFAULT, UNRESERVED_KEYWORD)
PG_KEYWORD("detail", K_DETAIL, UNRESERVED_KEYWORD)
PG_KEYWORD("diagnostics", K_DIAGNOSTICS, UNRESERVED_KEYWORD)
+ PG_KEYWORD("do", K_DO, UNRESERVED_KEYWORD)
PG_KEYWORD("dump", K_DUMP, UNRESERVED_KEYWORD)
PG_KEYWORD("elseif", K_ELSIF, UNRESERVED_KEYWORD)
PG_KEYWORD("elsif", K_ELSIF, UNRESERVED_KEYWORD)
PLpgSQL_stmt_type cmd_type;
int lineno;
PLpgSQL_expr *expr;
+ bool is_call;
PLpgSQL_variable *target;
} PLpgSQL_stmt_call;
bool retisset;
bool readonly_func;
+ bool atomic;
char *exitlabel; /* the "target" label of the current EXIT or
* CONTINUE stmt, if any */
*/
extern Datum plpgsql_exec_function(PLpgSQL_function *func,
FunctionCallInfo fcinfo,
- EState *simple_eval_estate);
+ EState *simple_eval_estate,
+ bool atomic);
extern HeapTuple plpgsql_exec_trigger(PLpgSQL_function *func,
TriggerData *trigdata);
extern void plpgsql_exec_event_trigger(PLpgSQL_function *func,
CREATE TABLE test1 (a int, b text);
-CREATE PROCEDURE transaction_test1()
+CREATE PROCEDURE transaction_test1(x int, y text)
LANGUAGE plpgsql
AS $$
BEGIN
- FOR i IN 0..9 LOOP
- INSERT INTO test1 (a) VALUES (i);
+ FOR i IN 0..x LOOP
+ INSERT INTO test1 (a, b) VALUES (i, y);
IF i % 2 = 0 THEN
COMMIT;
ELSE
END
$$;
-CALL transaction_test1();
+CALL transaction_test1(9, 'foo');
SELECT * FROM test1;
-- transaction commands not allowed when called in transaction block
START TRANSACTION;
-CALL transaction_test1();
+CALL transaction_test1(9, 'error');
COMMIT;
START TRANSACTION;
LANGUAGE plpgsql
AS $$
BEGIN
- CALL transaction_test1();
+ CALL transaction_test1(9, 'error');
RETURN 1;
END;
$$;
CALL transaction_test5();
+TRUNCATE test1;
+
+-- nested procedure calls
+CREATE PROCEDURE transaction_test6(c text)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ CALL transaction_test1(9, c);
+END;
+$$;
+
+CALL transaction_test6('bar');
+
+SELECT * FROM test1;
+
+TRUNCATE test1;
+
+CREATE PROCEDURE transaction_test7()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ DO 'BEGIN CALL transaction_test1(9, $x$baz$x$); END;';
+END;
+$$;
+
+CALL transaction_test7();
+
+SELECT * FROM test1;
+
+CREATE PROCEDURE transaction_test8()
+LANGUAGE plpgsql
+AS $$
+BEGIN
+ EXECUTE 'CALL transaction_test1(10, $x$baz$x$)';
+END;
+$$;
+
+CALL transaction_test8();
+
+
-- commit inside cursor loop
CREATE TABLE test2 (x int);
INSERT INTO test2 VALUES (0), (1), (2), (3), (4);
projects / postgresql / commitdiff