1996-07-09 08:22:35 +02:00
|
|
|
/*-------------------------------------------------------------------------
|
|
|
|
*
|
1999-02-14 00:22:53 +01:00
|
|
|
* dest.c
|
2002-02-27 20:36:13 +01:00
|
|
|
* support for communication destinations
|
|
|
|
*
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
2006-03-05 16:59:11 +01:00
|
|
|
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
|
2000-01-26 06:58:53 +01:00
|
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
* IDENTIFICATION
|
2006-08-12 04:52:06 +02:00
|
|
|
* $PostgreSQL: pgsql/src/backend/tcop/dest.c,v 1.69 2006/08/12 02:52:05 tgl Exp $
|
1996-07-09 08:22:35 +02:00
|
|
|
*
|
|
|
|
*-------------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
/*
|
1997-09-07 07:04:48 +02:00
|
|
|
* INTERFACE ROUTINES
|
2002-02-27 20:36:13 +01:00
|
|
|
* BeginCommand - initialize the destination at start of command
|
2003-05-06 22:26:28 +02:00
|
|
|
* CreateDestReceiver - create tuple receiver object for destination
|
2002-02-27 20:36:13 +01:00
|
|
|
* EndCommand - clean up the destination at end of command
|
1998-05-07 01:51:16 +02:00
|
|
|
* NullCommand - tell dest that an empty query string was recognized
|
|
|
|
* ReadyForQuery - tell dest that we are ready for a new query
|
1997-09-07 07:04:48 +02:00
|
|
|
*
|
|
|
|
* NOTES
|
|
|
|
* These routines do the appropriate work before and after
|
|
|
|
* tuples are returned by a query to keep the backend and the
|
|
|
|
* "destination" portals synchronized.
|
1996-07-09 08:22:35 +02:00
|
|
|
*/
|
1997-01-10 21:19:49 +01:00
|
|
|
|
1996-07-09 08:22:35 +02:00
|
|
|
#include "postgres.h"
|
|
|
|
|
1999-07-16 07:00:38 +02:00
|
|
|
#include "access/printtup.h"
|
2003-04-26 22:23:00 +02:00
|
|
|
#include "access/xact.h"
|
2006-08-12 04:52:06 +02:00
|
|
|
#include "executor/executor.h"
|
2003-05-08 20:16:37 +02:00
|
|
|
#include "executor/tstoreReceiver.h"
|
1998-01-26 02:42:53 +01:00
|
|
|
#include "libpq/libpq.h"
|
1999-04-25 05:19:27 +02:00
|
|
|
#include "libpq/pqformat.h"
|
2003-05-08 20:16:37 +02:00
|
|
|
#include "utils/portal.h"
|
1996-07-09 08:22:35 +02:00
|
|
|
|
|
|
|
|
|
|
|
/* ----------------
|
1999-01-27 01:36:28 +01:00
|
|
|
* dummy DestReceiver functions
|
1996-07-09 08:22:35 +02:00
|
|
|
* ----------------
|
|
|
|
*/
|
1997-01-08 09:39:10 +01:00
|
|
|
static void
|
2005-03-16 22:38:10 +01:00
|
|
|
donothingReceive(TupleTableSlot *slot, DestReceiver *self)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
|
|
|
}
|
|
|
|
|
1999-01-27 01:36:28 +01:00
|
|
|
static void
|
2003-05-08 20:16:37 +02:00
|
|
|
donothingStartup(DestReceiver *self, int operation, TupleDesc typeinfo)
|
1999-01-27 01:36:28 +01:00
|
|
|
{
|
|
|
|
}
|
1997-08-29 11:06:27 +02:00
|
|
|
|
1999-01-27 01:36:28 +01:00
|
|
|
static void
|
1999-05-26 00:43:53 +02:00
|
|
|
donothingCleanup(DestReceiver *self)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
2003-05-06 22:26:28 +02:00
|
|
|
/* this is used for both shutdown and destroy methods */
|
1999-01-27 01:36:28 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* ----------------
|
|
|
|
* static DestReceiver structs for dest types needing no local state
|
|
|
|
* ----------------
|
|
|
|
*/
|
|
|
|
static DestReceiver donothingDR = {
|
2003-05-06 22:26:28 +02:00
|
|
|
donothingReceive, donothingStartup, donothingCleanup, donothingCleanup,
|
2005-11-03 18:11:40 +01:00
|
|
|
DestNone
|
1999-01-27 01:36:28 +01:00
|
|
|
};
|
This patch implements holdable cursors, following the proposal
(materialization into a tuple store) discussed on pgsql-hackers earlier.
I've updated the documentation and the regression tests.
Notes on the implementation:
- I needed to change the tuple store API slightly -- it assumes that it
won't be used to hold data across transaction boundaries, so the temp
files that it uses for on-disk storage are automatically reclaimed at
end-of-transaction. I added a flag to tuplestore_begin_heap() to control
this behavior. Is changing the tuple store API in this fashion OK?
- in order to store executor results in a tuple store, I added a new
CommandDest. This works well for the most part, with one exception: the
current DestFunction API doesn't provide enough information to allow the
Executor to store results into an arbitrary tuple store (where the
particular tuple store to use is chosen by the call site of
ExecutorRun). To workaround this, I've temporarily hacked up a solution
that works, but is not ideal: since the receiveTuple DestFunction is
passed the portal name, we can use that to lookup the Portal data
structure for the cursor and then use that to get at the tuple store the
Portal is using. This unnecessarily ties the Portal code with the
tupleReceiver code, but it works...
The proper fix for this is probably to change the DestFunction API --
Tom suggested passing the full QueryDesc to the receiveTuple function.
In that case, callers of ExecutorRun could "subclass" QueryDesc to add
any additional fields that their particular CommandDest needed to get
access to. This approach would work, but I'd like to think about it for
a little bit longer before deciding which route to go. In the mean time,
the code works fine, so I don't think a fix is urgent.
- (semi-related) I added a NO SCROLL keyword to DECLARE CURSOR, and
adjusted the behavior of SCROLL in accordance with the discussion on
-hackers.
- (unrelated) Cleaned up some SGML markup in sql.sgml, copy.sgml
Neil Conway
2003-03-27 17:51:29 +01:00
|
|
|
|
1999-01-27 01:36:28 +01:00
|
|
|
static DestReceiver debugtupDR = {
|
2003-05-06 22:26:28 +02:00
|
|
|
debugtup, debugStartup, donothingCleanup, donothingCleanup,
|
2005-11-03 18:11:40 +01:00
|
|
|
DestDebug
|
1999-01-27 01:36:28 +01:00
|
|
|
};
|
This patch implements holdable cursors, following the proposal
(materialization into a tuple store) discussed on pgsql-hackers earlier.
I've updated the documentation and the regression tests.
Notes on the implementation:
- I needed to change the tuple store API slightly -- it assumes that it
won't be used to hold data across transaction boundaries, so the temp
files that it uses for on-disk storage are automatically reclaimed at
end-of-transaction. I added a flag to tuplestore_begin_heap() to control
this behavior. Is changing the tuple store API in this fashion OK?
- in order to store executor results in a tuple store, I added a new
CommandDest. This works well for the most part, with one exception: the
current DestFunction API doesn't provide enough information to allow the
Executor to store results into an arbitrary tuple store (where the
particular tuple store to use is chosen by the call site of
ExecutorRun). To workaround this, I've temporarily hacked up a solution
that works, but is not ideal: since the receiveTuple DestFunction is
passed the portal name, we can use that to lookup the Portal data
structure for the cursor and then use that to get at the tuple store the
Portal is using. This unnecessarily ties the Portal code with the
tupleReceiver code, but it works...
The proper fix for this is probably to change the DestFunction API --
Tom suggested passing the full QueryDesc to the receiveTuple function.
In that case, callers of ExecutorRun could "subclass" QueryDesc to add
any additional fields that their particular CommandDest needed to get
access to. This approach would work, but I'd like to think about it for
a little bit longer before deciding which route to go. In the mean time,
the code works fine, so I don't think a fix is urgent.
- (semi-related) I added a NO SCROLL keyword to DECLARE CURSOR, and
adjusted the behavior of SCROLL in accordance with the discussion on
-hackers.
- (unrelated) Cleaned up some SGML markup in sql.sgml, copy.sgml
Neil Conway
2003-03-27 17:51:29 +01:00
|
|
|
|
1999-01-27 01:36:28 +01:00
|
|
|
static DestReceiver spi_printtupDR = {
|
2003-05-06 22:26:28 +02:00
|
|
|
spi_printtup, spi_dest_startup, donothingCleanup, donothingCleanup,
|
2005-11-03 18:11:40 +01:00
|
|
|
DestSPI
|
1999-01-27 01:36:28 +01:00
|
|
|
};
|
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
/* Globally available receiver for DestNone */
|
2003-05-06 22:26:28 +02:00
|
|
|
DestReceiver *None_Receiver = &donothingDR;
|
|
|
|
|
|
|
|
|
1999-01-27 01:36:28 +01:00
|
|
|
/* ----------------
|
2002-02-27 20:36:13 +01:00
|
|
|
* BeginCommand - initialize the destination at start of command
|
1999-01-27 01:36:28 +01:00
|
|
|
* ----------------
|
|
|
|
*/
|
|
|
|
void
|
2002-02-27 20:36:13 +01:00
|
|
|
BeginCommand(const char *commandTag, CommandDest dest)
|
1999-01-27 01:36:28 +01:00
|
|
|
{
|
2002-02-27 20:36:13 +01:00
|
|
|
/* Nothing to do at present */
|
1999-01-27 01:36:28 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* ----------------
|
2003-05-06 22:26:28 +02:00
|
|
|
* CreateDestReceiver - return appropriate receiver function set for dest
|
2003-05-08 20:16:37 +02:00
|
|
|
*
|
2005-11-03 18:11:40 +01:00
|
|
|
* Note: a Portal must be specified for destinations DestRemote,
|
|
|
|
* DestRemoteExecute, and DestTuplestore. It can be NULL for the others.
|
1999-01-27 01:36:28 +01:00
|
|
|
* ----------------
|
|
|
|
*/
|
1999-05-25 18:15:34 +02:00
|
|
|
DestReceiver *
|
2003-05-08 20:16:37 +02:00
|
|
|
CreateDestReceiver(CommandDest dest, Portal portal)
|
1999-01-27 01:36:28 +01:00
|
|
|
{
|
|
|
|
switch (dest)
|
|
|
|
{
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestRemote:
|
|
|
|
case DestRemoteExecute:
|
2003-05-08 20:16:37 +02:00
|
|
|
if (portal == NULL)
|
2005-11-03 18:11:40 +01:00
|
|
|
elog(ERROR, "no portal specified for DestRemote receiver");
|
2003-05-08 20:16:37 +02:00
|
|
|
return printtup_create_DR(dest, portal);
|
2003-05-05 02:44:56 +02:00
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestNone:
|
2003-05-05 02:44:56 +02:00
|
|
|
return &donothingDR;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestDebug:
|
1999-05-25 18:15:34 +02:00
|
|
|
return &debugtupDR;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestSPI:
|
1999-05-25 18:15:34 +02:00
|
|
|
return &spi_printtupDR;
|
1997-09-07 07:04:48 +02:00
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestTuplestore:
|
2003-05-08 20:16:37 +02:00
|
|
|
if (portal == NULL)
|
2005-11-03 18:11:40 +01:00
|
|
|
elog(ERROR, "no portal specified for DestTuplestore receiver");
|
2003-05-08 20:16:37 +02:00
|
|
|
if (portal->holdStore == NULL ||
|
|
|
|
portal->holdContext == NULL)
|
2003-07-22 21:00:12 +02:00
|
|
|
elog(ERROR, "portal has no holdStore");
|
2003-05-08 20:16:37 +02:00
|
|
|
return CreateTuplestoreDestReceiver(portal->holdStore,
|
|
|
|
portal->holdContext);
|
2006-08-12 04:52:06 +02:00
|
|
|
|
|
|
|
case DestIntoRel:
|
|
|
|
return CreateIntoRelDestReceiver();
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
|
|
|
|
2002-02-27 20:36:13 +01:00
|
|
|
/* should never get here */
|
1999-05-25 18:15:34 +02:00
|
|
|
return &donothingDR;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/* ----------------
|
2002-02-27 20:36:13 +01:00
|
|
|
* EndCommand - clean up the destination at end of command
|
1996-07-09 08:22:35 +02:00
|
|
|
* ----------------
|
|
|
|
*/
|
|
|
|
void
|
2002-02-26 23:47:12 +01:00
|
|
|
EndCommand(const char *commandTag, CommandDest dest)
|
1996-07-09 08:22:35 +02:00
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
switch (dest)
|
|
|
|
{
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestRemote:
|
|
|
|
case DestRemoteExecute:
|
2002-02-26 23:47:12 +01:00
|
|
|
pq_puttextmessage('C', commandTag);
|
1997-09-08 04:41:22 +02:00
|
|
|
break;
|
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestNone:
|
|
|
|
case DestDebug:
|
|
|
|
case DestSPI:
|
|
|
|
case DestTuplestore:
|
2006-08-12 04:52:06 +02:00
|
|
|
case DestIntoRel:
|
1997-09-08 04:41:22 +02:00
|
|
|
break;
|
1997-09-07 07:04:48 +02:00
|
|
|
}
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
/* ----------------
|
1998-05-07 01:51:16 +02:00
|
|
|
* NullCommand - tell dest that an empty query string was recognized
|
1997-09-07 07:04:48 +02:00
|
|
|
*
|
1998-05-07 01:51:16 +02:00
|
|
|
* In FE/BE protocol version 1.0, this hack is necessary to support
|
|
|
|
* libpq's crufty way of determining whether a multiple-command
|
|
|
|
* query string is done. In protocol 2.0 it's probably not really
|
|
|
|
* necessary to distinguish empty queries anymore, but we still do it
|
2003-04-22 02:08:07 +02:00
|
|
|
* for backwards compatibility with 1.0. In protocol 3.0 it has some
|
|
|
|
* use again, since it ensures that there will be a recognizable end
|
|
|
|
* to the response to an Execute message.
|
1996-07-09 08:22:35 +02:00
|
|
|
* ----------------
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
NullCommand(CommandDest dest)
|
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
switch (dest)
|
|
|
|
{
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestRemote:
|
|
|
|
case DestRemoteExecute:
|
2001-03-22 07:16:21 +01:00
|
|
|
|
|
|
|
/*
|
2005-10-15 04:49:52 +02:00
|
|
|
* tell the fe that we saw an empty query string. In protocols
|
|
|
|
* before 3.0 this has a useless empty-string message body.
|
1999-01-27 01:36:28 +01:00
|
|
|
*/
|
2003-04-22 02:08:07 +02:00
|
|
|
if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
|
|
|
|
pq_putemptymessage('I');
|
|
|
|
else
|
|
|
|
pq_puttextmessage('I', "");
|
1998-05-07 01:51:16 +02:00
|
|
|
break;
|
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestNone:
|
|
|
|
case DestDebug:
|
|
|
|
case DestSPI:
|
|
|
|
case DestTuplestore:
|
2006-08-12 04:52:06 +02:00
|
|
|
case DestIntoRel:
|
1998-05-07 01:51:16 +02:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* ----------------
|
|
|
|
* ReadyForQuery - tell dest that we are ready for a new query
|
|
|
|
*
|
|
|
|
* The ReadyForQuery message is sent in protocol versions 2.0 and up
|
|
|
|
* so that the FE can tell when we are done processing a query string.
|
2003-04-26 22:23:00 +02:00
|
|
|
* In versions 3.0 and up, it also carries a transaction state indicator.
|
1998-05-07 01:51:16 +02:00
|
|
|
*
|
|
|
|
* Note that by flushing the stdio buffer here, we can avoid doing it
|
|
|
|
* most other places and thus reduce the number of separate packets sent.
|
|
|
|
* ----------------
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ReadyForQuery(CommandDest dest)
|
|
|
|
{
|
1997-09-07 07:04:48 +02:00
|
|
|
switch (dest)
|
|
|
|
{
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestRemote:
|
|
|
|
case DestRemoteExecute:
|
2003-04-26 22:23:00 +02:00
|
|
|
if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
|
|
|
|
{
|
|
|
|
StringInfoData buf;
|
|
|
|
|
|
|
|
pq_beginmessage(&buf, 'Z');
|
|
|
|
pq_sendbyte(&buf, TransactionBlockStatusCode());
|
|
|
|
pq_endmessage(&buf);
|
|
|
|
}
|
|
|
|
else if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
|
2003-04-22 02:08:07 +02:00
|
|
|
pq_putemptymessage('Z');
|
1999-01-27 01:36:28 +01:00
|
|
|
/* Flush output at end of cycle in any case. */
|
|
|
|
pq_flush();
|
1997-09-08 04:41:22 +02:00
|
|
|
break;
|
|
|
|
|
2005-11-03 18:11:40 +01:00
|
|
|
case DestNone:
|
|
|
|
case DestDebug:
|
|
|
|
case DestSPI:
|
|
|
|
case DestTuplestore:
|
2006-08-12 04:52:06 +02:00
|
|
|
case DestIntoRel:
|
1997-09-08 04:41:22 +02:00
|
|
|
break;
|
1996-07-09 08:22:35 +02:00
|
|
|
}
|
|
|
|
}
|