I wrote:
> ... PFA a patch
> that invents a notion of an "implicit" transaction block.
On further consideration, I think the control logic I added in
exec_simple_query() is a shade bogus. I set it up to only force
an implicit transaction block when there are at least two statements
remaining to execute. However, that has the result of allowing, eg,
begin\; select 1\; commit\; vacuum;
Now in principle it's perfectly OK to allow that, since the vacuum
is alone in its transaction. But it feels more like an implementation
artifact than a good design. The existing code doesn't allow it,
and we might have a hard time duplicating this behavior if we ever
significantly rewrote the transaction infrastructure. Plus I'd hate
to have to explain it to users. I think we'd be better off enforcing
transaction block restrictions on every statement in a multi-command
string, regardless of the location of any COMMIT/ROLLBACK within the
string.
Hence, attached a v2 that does it like that. I also fully reverted
4f896dac1 by undoing its changes to PreventTransactionChain; other
than that, the changes in xact.c are the same as before.
regards, tom lane
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 5e7e812..8b33676 100644
*** a/src/backend/access/transam/xact.c
--- b/src/backend/access/transam/xact.c
*************** typedef enum TBlockState
*** 145,150 ****
--- 145,151 ----
/* transaction block states */
TBLOCK_BEGIN, /* starting transaction block */
TBLOCK_INPROGRESS, /* live transaction */
+ TBLOCK_IMPLICIT_INPROGRESS, /* live transaction after implicit BEGIN */
TBLOCK_PARALLEL_INPROGRESS, /* live transaction inside parallel worker */
TBLOCK_END, /* COMMIT received */
TBLOCK_ABORT, /* failed xact, awaiting ROLLBACK */
*************** StartTransactionCommand(void)
*** 2700,2705 ****
--- 2701,2707 ----
* previous CommitTransactionCommand.)
*/
case TBLOCK_INPROGRESS:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
break;
*************** CommitTransactionCommand(void)
*** 2790,2795 ****
--- 2792,2798 ----
* counter and return.
*/
case TBLOCK_INPROGRESS:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
CommandCounterIncrement();
break;
*************** AbortCurrentTransaction(void)
*** 3014,3023 ****
break;
/*
! * if we aren't in a transaction block, we just do the basic abort
! * & cleanup transaction.
*/
case TBLOCK_STARTED:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
--- 3017,3028 ----
break;
/*
! * If we aren't in a transaction block, we just do the basic abort
! * & cleanup transaction. For this purpose, we treat an implicit
! * transaction block as if it were a simple statement.
*/
case TBLOCK_STARTED:
+ case TBLOCK_IMPLICIT_INPROGRESS:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
*************** AbortCurrentTransaction(void)
*** 3148,3156 ****
* completes). Subtransactions are verboten too.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
! * inside a function or multi-query querystring. (We will always fail if
! * this is false, but it's convenient to centralize the check here instead of
! * making callers do it.)
* stmtType: statement type name, for error messages.
*/
void
--- 3153,3160 ----
* completes). Subtransactions are verboten too.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
! * inside a function. (We will always fail if this is false, but it's
! * convenient to centralize the check here instead of making callers do it.)
* stmtType: statement type name, for error messages.
*/
void
*************** PreventTransactionChain(bool isTopLevel,
*** 3183,3190 ****
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
! errmsg("%s cannot be executed from a function or multi-command string",
! stmtType)));
/* If we got past IsTransactionBlock test, should be in default state */
if (CurrentTransactionState->blockState != TBLOCK_DEFAULT &&
--- 3187,3193 ----
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
! errmsg("%s cannot be executed from a function", stmtType)));
/* If we got past IsTransactionBlock test, should be in default state */
if (CurrentTransactionState->blockState != TBLOCK_DEFAULT &&
*************** BeginTransactionBlock(void)
*** 3429,3434 ****
--- 3432,3446 ----
break;
/*
+ * BEGIN converts an implicit transaction block to a regular one.
+ * (Note that we allow this even if we've already done some
+ * commands, which is a bit odd but matches historical practice.)
+ */
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ s->blockState = TBLOCK_BEGIN;
+ break;
+
+ /*
* Already a transaction block in progress.
*/
case TBLOCK_INPROGRESS:
*************** PrepareTransactionBlock(char *gid)
*** 3503,3509 ****
* ignore case where we are not in a transaction;
* EndTransactionBlock already issued a warning.
*/
! Assert(s->blockState == TBLOCK_STARTED);
/* Don't send back a PREPARE result tag... */
result = false;
}
--- 3515,3522 ----
* ignore case where we are not in a transaction;
* EndTransactionBlock already issued a warning.
*/
! Assert(s->blockState == TBLOCK_STARTED ||
! s->blockState == TBLOCK_IMPLICIT_INPROGRESS);
/* Don't send back a PREPARE result tag... */
result = false;
}
*************** EndTransactionBlock(void)
*** 3542,3547 ****
--- 3555,3572 ----
break;
/*
+ * In an implicit transaction block, commit, but issue a warning
+ * because there was no explicit BEGIN before this.
+ */
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ ereport(WARNING,
+ (errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
+ errmsg("there is no transaction in progress")));
+ s->blockState = TBLOCK_END;
+ result = true;
+ break;
+
+ /*
* We are in a failed transaction block. Tell
* CommitTransactionCommand it's time to exit the block.
*/
*************** UserAbortTransactionBlock(void)
*** 3705,3712 ****
--- 3730,3743 ----
* WARNING and go to abort state. The upcoming call to
* CommitTransactionCommand() will then put us back into the
* default state.
+ *
+ * We do the same thing with ABORT inside an implicit transaction,
+ * although in this case we might be rolling back actual database
+ * state changes. (It's debatable whether we should issue a
+ * WARNING in this case, but we have done so historically.)
*/
case TBLOCK_STARTED:
+ case TBLOCK_IMPLICIT_INPROGRESS:
ereport(WARNING,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
errmsg("there is no transaction in progress")));
*************** UserAbortTransactionBlock(void)
*** 3744,3749 ****
--- 3775,3832 ----
}
/*
+ * BeginImplicitTransactionBlock
+ * Start an implicit transaction block if we're not already in one.
+ *
+ * Unlike BeginTransactionBlock, this is called directly from the main loop
+ * in postgres.c, not within a Portal. So we can just change blockState
+ * without a lot of ceremony. We do not expect caller to do
+ * CommitTransactionCommand/StartTransactionCommand.
+ */
+ void
+ BeginImplicitTransactionBlock(void)
+ {
+ TransactionState s = CurrentTransactionState;
+
+ /*
+ * If we are in STARTED state (that is, no transaction block is open),
+ * switch to IMPLICIT_INPROGRESS state, creating an implicit transaction
+ * block.
+ *
+ * For caller convenience, we consider all other transaction states as
+ * legal here; otherwise the caller would need its own state check, which
+ * seems rather pointless.
+ */
+ if (s->blockState == TBLOCK_STARTED)
+ s->blockState = TBLOCK_IMPLICIT_INPROGRESS;
+ }
+
+ /*
+ * EndImplicitTransactionBlock
+ * End an implicit transaction block, if we're in one.
+ *
+ * Like EndTransactionBlock, we just make any needed blockState change here.
+ * The real work will be done in the upcoming CommitTransactionCommand().
+ */
+ void
+ EndImplicitTransactionBlock(void)
+ {
+ TransactionState s = CurrentTransactionState;
+
+ /*
+ * If we are in IMPLICIT_INPROGRESS state, switch back to STARTED state,
+ * allowing CommitTransactionCommand to commit whatever happened during
+ * the implicit transaction block as though it were a single statement.
+ *
+ * For caller convenience, we consider all other transaction states as
+ * legal here; otherwise the caller would need its own state check, which
+ * seems rather pointless.
+ */
+ if (s->blockState == TBLOCK_IMPLICIT_INPROGRESS)
+ s->blockState = TBLOCK_STARTED;
+ }
+
+ /*
* DefineSavepoint
* This executes a SAVEPOINT command.
*/
*************** DefineSavepoint(char *name)
*** 3780,3785 ****
--- 3863,3877 ----
s->name = MemoryContextStrdup(TopTransactionContext, name);
break;
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ /* Disallow SAVEPOINT in an implicit transaction */
+ ereport(ERROR,
+ (errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
+ /* translator: %s represents an SQL statement name */
+ errmsg("%s can only be used in transaction blocks",
+ "SAVEPOINT")));
+ break;
+
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
*************** ReleaseSavepoint(List *options)
*** 3834,3841 ****
switch (s->blockState)
{
/*
! * We can't rollback to a savepoint if there is no savepoint
! * defined.
*/
case TBLOCK_INPROGRESS:
ereport(ERROR,
--- 3926,3932 ----
switch (s->blockState)
{
/*
! * We can't release a savepoint if there is no savepoint defined.
*/
case TBLOCK_INPROGRESS:
ereport(ERROR,
*************** ReleaseSavepoint(List *options)
*** 3843,3848 ****
--- 3934,3948 ----
errmsg("no such savepoint")));
break;
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ /* Disallow RELEASE SAVEPOINT in an implicit transaction */
+ ereport(ERROR,
+ (errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
+ /* translator: %s represents an SQL statement name */
+ errmsg("%s can only be used in transaction blocks",
+ "RELEASE SAVEPOINT")));
+ break;
+
/*
* We are in a non-aborted subtransaction. This is the only valid
* case.
*************** RollbackToSavepoint(List *options)
*** 3957,3962 ****
--- 4057,4071 ----
errmsg("no such savepoint")));
break;
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ /* Disallow ROLLBACK TO SAVEPOINT in an implicit transaction */
+ ereport(ERROR,
+ (errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
+ /* translator: %s represents an SQL statement name */
+ errmsg("%s can only be used in transaction blocks",
+ "ROLLBACK TO SAVEPOINT")));
+ break;
+
/*
* There is at least one savepoint, so proceed.
*/
*************** RollbackToSavepoint(List *options)
*** 4046,4056 ****
/*
* BeginInternalSubTransaction
* This is the same as DefineSavepoint except it allows TBLOCK_STARTED,
! * TBLOCK_END, and TBLOCK_PREPARE states, and therefore it can safely be
! * used in functions that might be called when not inside a BEGIN block
! * or when running deferred triggers at COMMIT/PREPARE time. Also, it
! * automatically does CommitTransactionCommand/StartTransactionCommand
! * instead of expecting the caller to do it.
*/
void
BeginInternalSubTransaction(char *name)
--- 4155,4166 ----
/*
* BeginInternalSubTransaction
* This is the same as DefineSavepoint except it allows TBLOCK_STARTED,
! * TBLOCK_IMPLICIT_INPROGRESS, TBLOCK_END, and TBLOCK_PREPARE states,
! * and therefore it can safely be used in functions that might be called
! * when not inside a BEGIN block or when running deferred triggers at
! * COMMIT/PREPARE time. Also, it automatically does
! * CommitTransactionCommand/StartTransactionCommand instead of expecting
! * the caller to do it.
*/
void
BeginInternalSubTransaction(char *name)
*************** BeginInternalSubTransaction(char *name)
*** 4076,4081 ****
--- 4186,4192 ----
{
case TBLOCK_STARTED:
case TBLOCK_INPROGRESS:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_END:
case TBLOCK_PREPARE:
case TBLOCK_SUBINPROGRESS:
*************** RollbackAndReleaseCurrentSubTransaction(
*** 4180,4185 ****
--- 4291,4297 ----
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_INPROGRESS:
*************** RollbackAndReleaseCurrentSubTransaction(
*** 4211,4216 ****
--- 4323,4329 ----
s = CurrentTransactionState; /* changed by pop */
AssertState(s->blockState == TBLOCK_SUBINPROGRESS ||
s->blockState == TBLOCK_INPROGRESS ||
+ s->blockState == TBLOCK_IMPLICIT_INPROGRESS ||
s->blockState == TBLOCK_STARTED);
}
*************** AbortOutOfAnyTransaction(void)
*** 4259,4264 ****
--- 4372,4378 ----
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_INPROGRESS:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_END:
case TBLOCK_ABORT_PENDING:
*************** TransactionBlockStatusCode(void)
*** 4369,4374 ****
--- 4483,4489 ----
case TBLOCK_BEGIN:
case TBLOCK_SUBBEGIN:
case TBLOCK_INPROGRESS:
+ case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
case TBLOCK_END:
*************** BlockStateAsString(TBlockState blockStat
*** 5036,5041 ****
--- 5151,5158 ----
return "BEGIN";
case TBLOCK_INPROGRESS:
return "INPROGRESS";
+ case TBLOCK_IMPLICIT_INPROGRESS:
+ return "IMPLICIT_INPROGRESS";
case TBLOCK_PARALLEL_INPROGRESS:
return "PARALLEL_INPROGRESS";
case TBLOCK_END:
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 8d3fecf..c10d891 100644
*** a/src/backend/tcop/postgres.c
--- b/src/backend/tcop/postgres.c
*************** exec_simple_query(const char *query_stri
*** 883,892 ****
ListCell *parsetree_item;
bool save_log_statement_stats = log_statement_stats;
bool was_logged = false;
! bool isTopLevel;
char msec_str[32];
-
/*
* Report query to various monitoring facilities.
*/
--- 883,891 ----
ListCell *parsetree_item;
bool save_log_statement_stats = log_statement_stats;
bool was_logged = false;
! bool use_implicit_block;
char msec_str[32];
/*
* Report query to various monitoring facilities.
*/
*************** exec_simple_query(const char *query_stri
*** 947,959 ****
MemoryContextSwitchTo(oldcontext);
/*
! * We'll tell PortalRun it's a top-level command iff there's exactly one
! * raw parsetree. If more than one, it's effectively a transaction block
! * and we want PreventTransactionChain to reject unsafe commands. (Note:
! * we're assuming that query rewrite cannot add commands that are
! * significant to PreventTransactionChain.)
*/
! isTopLevel = (list_length(parsetree_list) == 1);
/*
* Run through the raw parsetree(s) and process each one.
--- 946,959 ----
MemoryContextSwitchTo(oldcontext);
/*
! * For historical reasons, if multiple SQL statements are given in a
! * single "simple Query" message, we execute them as a single transaction,
! * unless explicit transaction control commands are included to make
! * portions of the list be separate transactions. To represent this
! * behavior properly in the transaction machinery, we use an "implicit"
! * transaction block.
*/
! use_implicit_block = (list_length(parsetree_list) > 1);
/*
* Run through the raw parsetree(s) and process each one.
*************** exec_simple_query(const char *query_stri
*** 1001,1006 ****
--- 1001,1016 ----
/* Make sure we are in a transaction command */
start_xact_command();
+ /*
+ * If using an implicit transaction block, and we're not already in a
+ * transaction block, start an implicit block to force this statement
+ * to be grouped together with any following ones. (We must do this
+ * each time through the loop; otherwise, a COMMIT/ROLLBACK in the
+ * list would cause later statements to not be grouped.)
+ */
+ if (use_implicit_block)
+ BeginImplicitTransactionBlock();
+
/* If we got a cancel signal in parsing or prior command, quit */
CHECK_FOR_INTERRUPTS();
*************** exec_simple_query(const char *query_stri
*** 1098,1104 ****
*/
(void) PortalRun(portal,
FETCH_ALL,
! isTopLevel,
true,
receiver,
receiver,
--- 1108,1114 ----
*/
(void) PortalRun(portal,
FETCH_ALL,
! true, /* always top level */
true,
receiver,
receiver,
*************** exec_simple_query(const char *query_stri
*** 1108,1122 ****
PortalDrop(portal, false);
! if (IsA(parsetree->stmt, TransactionStmt))
! {
! /*
! * If this was a transaction control statement, commit it. We will
! * start a new xact command for the next command (if any).
! */
! finish_xact_command();
! }
! else if (lnext(parsetree_item) == NULL)
{
/*
* If this is the last parsetree of the query string, close down
--- 1118,1124 ----
PortalDrop(portal, false);
! if (lnext(parsetree_item) == NULL)
{
/*
* If this is the last parsetree of the query string, close down
*************** exec_simple_query(const char *query_stri
*** 1124,1132 ****
* is so that any end-of-transaction errors are reported before
* the command-complete message is issued, to avoid confusing
* clients who will expect either a command-complete message or an
! * error, not one and then the other. But for compatibility with
! * historical Postgres behavior, we do not force a transaction
! * boundary between queries appearing in a single query string.
*/
finish_xact_command();
}
--- 1126,1143 ----
* is so that any end-of-transaction errors are reported before
* the command-complete message is issued, to avoid confusing
* clients who will expect either a command-complete message or an
! * error, not one and then the other. Also, if we're using an
! * implicit transaction block, we must close that out first.
! */
! if (use_implicit_block)
! EndImplicitTransactionBlock();
! finish_xact_command();
! }
! else if (IsA(parsetree->stmt, TransactionStmt))
! {
! /*
! * If this was a transaction control statement, commit it. We will
! * start a new xact command for the next command.
*/
finish_xact_command();
}
*************** exec_simple_query(const char *query_stri
*** 1149,1155 ****
} /* end loop over parsetrees */
/*
! * Close down transaction statement, if one is open.
*/
finish_xact_command();
--- 1160,1168 ----
} /* end loop over parsetrees */
/*
! * Close down transaction statement, if one is open. (This will only do
! * something if the parsetree list was empty; otherwise the last loop
! * iteration already did it.)
*/
finish_xact_command();
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index ad5aad9..f2c10f9 100644
*** a/src/include/access/xact.h
--- b/src/include/access/xact.h
*************** extern void BeginTransactionBlock(void);
*** 352,357 ****
--- 352,359 ----
extern bool EndTransactionBlock(void);
extern bool PrepareTransactionBlock(char *gid);
extern void UserAbortTransactionBlock(void);
+ extern void BeginImplicitTransactionBlock(void);
+ extern void EndImplicitTransactionBlock(void);
extern void ReleaseSavepoint(List *options);
extern void DefineSavepoint(char *name);
extern void RollbackToSavepoint(List *options);
diff --git a/src/test/regress/expected/transactions.out b/src/test/regress/expected/transactions.out
index d9b702d..a7fdcf4 100644
*** a/src/test/regress/expected/transactions.out
--- b/src/test/regress/expected/transactions.out
*************** ERROR: portal "ctt" cannot be run
*** 659,664 ****
--- 659,748 ----
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;
+ ?column?
+ ----------
+ 3
+ (1 row)
+
+ -- this implicitly commits:
+ insert into i_table values(1)\; select * from i_table;
+ f1
+ ----
+ 1
+ (1 row)
+
+ -- 1/0 error will cause rolling back the whole implicit transaction
+ insert into i_table values(2)\; select * from i_table\; select 1/0;
+ ERROR: division by zero
+ select * from i_table;
+ f1
+ ----
+ 1
+ (1 row)
+
+ rollback; -- we are not in a transaction at this point
+ WARNING: there is no transaction in progress
+ -- 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
+ WARNING: there is no transaction in progress
+ begin\; insert into i_table values(4)\; rollback;
+ rollback; -- we are not in a transaction at this point
+ WARNING: there is no transaction in progress
+ -- 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;
+ WARNING: there is no transaction in progress
+ ERROR: division by zero
+ -- similarly, rollback aborts but issues a warning.
+ insert into i_table values(9)\; rollback\; select 2;
+ WARNING: there is no transaction in progress
+ ?column?
+ ----------
+ 2
+ (1 row)
+
+ select * from i_table;
+ f1
+ ----
+ 1
+ 3
+ 5
+ 7
+ (4 rows)
+
+ rollback; -- we are not in a transaction at this point
+ WARNING: there is no transaction in progress
+ -- implicit transaction block is still a transaction block, for e.g. VACUUM
+ SELECT 1\; VACUUM;
+ ERROR: VACUUM cannot run inside a transaction block
+ SELECT 1\; COMMIT\; VACUUM;
+ WARNING: there is no transaction in progress
+ ERROR: VACUUM cannot run inside a transaction block
+ -- we disallow savepoint-related commands in implicit-transaction state
+ SELECT 1\; SAVEPOINT sp;
+ ERROR: SAVEPOINT can only be used in transaction blocks
+ SELECT 1\; COMMIT\; SAVEPOINT sp;
+ WARNING: there is no transaction in progress
+ ERROR: SAVEPOINT can only be used in transaction blocks
+ ROLLBACK TO SAVEPOINT sp\; SELECT 2;
+ ERROR: ROLLBACK TO SAVEPOINT can only be used in transaction blocks
+ SELECT 2\; RELEASE SAVEPOINT sp\; SELECT 3;
+ ERROR: RELEASE SAVEPOINT can only be used in transaction blocks
+ -- 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;
diff --git a/src/test/regress/sql/transactions.sql b/src/test/regress/sql/transactions.sql
index bf9cb05..82661ab 100644
*** a/src/test/regress/sql/transactions.sql
--- b/src/test/regress/sql/transactions.sql
*************** DROP FUNCTION create_temp_tab();
*** 419,424 ****
--- 419,478 ----
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.
--
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