mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-30 23:07:20 +02:00
The backend was using strings to represent command tags and doing string comparisons in multiple places, but that's slow and unhelpful. Create a new command list with a supporting structure to use instead; this is stored in a tag-list-file that can be tailored to specific purposes with a caller-definable C macro, similar to what we do for WAL resource managers. The first first such uses are a new CommandTag enum and a CommandTagBehavior struct. Replace numerous occurrences of char *completionTag with a QueryCompletion struct so that the code no longer stores information about completed queries in a cstring. Only at the last moment, in EndCommand(), does this get converted to a string. EventTriggerCacheItem no longer holds an array of palloc’d tag strings in sorted order, but rather just a Bitmapset over the CommandTags. Author: Mark Dilger, with unsolicited help from Álvaro Herrera Reviewed-by: John Naylor, Tom Lane Discussion: https://postgr.es/m/981A9DB4-3F0C-4DA5-88AD-CB9CFF4D6CAD@enterprisedb.com
303 lines
7.4 KiB
C
303 lines
7.4 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* dest.c
|
|
* support for communication destinations
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* IDENTIFICATION
|
|
* src/backend/tcop/dest.c
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
/*
|
|
* INTERFACE ROUTINES
|
|
* BeginCommand - initialize the destination at start of command
|
|
* CreateDestReceiver - create tuple receiver object for destination
|
|
* EndCommand - clean up the destination at end of command
|
|
* NullCommand - tell dest that an empty query string was recognized
|
|
* ReadyForQuery - tell dest that we are ready for a new query
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include "postgres.h"
|
|
|
|
#include "access/printsimple.h"
|
|
#include "access/printtup.h"
|
|
#include "access/xact.h"
|
|
#include "commands/copy.h"
|
|
#include "commands/createas.h"
|
|
#include "commands/matview.h"
|
|
#include "executor/functions.h"
|
|
#include "executor/tqueue.h"
|
|
#include "executor/tstoreReceiver.h"
|
|
#include "libpq/libpq.h"
|
|
#include "libpq/pqformat.h"
|
|
#include "utils/portal.h"
|
|
|
|
|
|
/* ----------------
|
|
* dummy DestReceiver functions
|
|
* ----------------
|
|
*/
|
|
static bool
|
|
donothingReceive(TupleTableSlot *slot, DestReceiver *self)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static void
|
|
donothingStartup(DestReceiver *self, int operation, TupleDesc typeinfo)
|
|
{
|
|
}
|
|
|
|
static void
|
|
donothingCleanup(DestReceiver *self)
|
|
{
|
|
/* this is used for both shutdown and destroy methods */
|
|
}
|
|
|
|
/* ----------------
|
|
* static DestReceiver structs for dest types needing no local state
|
|
* ----------------
|
|
*/
|
|
static const DestReceiver donothingDR = {
|
|
donothingReceive, donothingStartup, donothingCleanup, donothingCleanup,
|
|
DestNone
|
|
};
|
|
|
|
static const DestReceiver debugtupDR = {
|
|
debugtup, debugStartup, donothingCleanup, donothingCleanup,
|
|
DestDebug
|
|
};
|
|
|
|
static const DestReceiver printsimpleDR = {
|
|
printsimple, printsimple_startup, donothingCleanup, donothingCleanup,
|
|
DestRemoteSimple
|
|
};
|
|
|
|
static const DestReceiver spi_printtupDR = {
|
|
spi_printtup, spi_dest_startup, donothingCleanup, donothingCleanup,
|
|
DestSPI
|
|
};
|
|
|
|
/*
|
|
* Globally available receiver for DestNone.
|
|
*
|
|
* It's ok to cast the constness away as any modification of the none receiver
|
|
* would be a bug (which gets easier to catch this way).
|
|
*/
|
|
DestReceiver *None_Receiver = (DestReceiver *) &donothingDR;
|
|
|
|
/* ----------------
|
|
* BeginCommand - initialize the destination at start of command
|
|
* ----------------
|
|
*/
|
|
void
|
|
BeginCommand(CommandTag commandTag, CommandDest dest)
|
|
{
|
|
/* Nothing to do at present */
|
|
}
|
|
|
|
/* ----------------
|
|
* CreateDestReceiver - return appropriate receiver function set for dest
|
|
* ----------------
|
|
*/
|
|
DestReceiver *
|
|
CreateDestReceiver(CommandDest dest)
|
|
{
|
|
/*
|
|
* It's ok to cast the constness away as any modification of the none
|
|
* receiver would be a bug (which gets easier to catch this way).
|
|
*/
|
|
|
|
switch (dest)
|
|
{
|
|
case DestRemote:
|
|
case DestRemoteExecute:
|
|
return printtup_create_DR(dest);
|
|
|
|
case DestRemoteSimple:
|
|
return unconstify(DestReceiver *, &printsimpleDR);
|
|
|
|
case DestNone:
|
|
return unconstify(DestReceiver *, &donothingDR);
|
|
|
|
case DestDebug:
|
|
return unconstify(DestReceiver *, &debugtupDR);
|
|
|
|
case DestSPI:
|
|
return unconstify(DestReceiver *, &spi_printtupDR);
|
|
|
|
case DestTuplestore:
|
|
return CreateTuplestoreDestReceiver();
|
|
|
|
case DestIntoRel:
|
|
return CreateIntoRelDestReceiver(NULL);
|
|
|
|
case DestCopyOut:
|
|
return CreateCopyDestReceiver();
|
|
|
|
case DestSQLFunction:
|
|
return CreateSQLFunctionDestReceiver();
|
|
|
|
case DestTransientRel:
|
|
return CreateTransientRelDestReceiver(InvalidOid);
|
|
|
|
case DestTupleQueue:
|
|
return CreateTupleQueueDestReceiver(NULL);
|
|
}
|
|
|
|
/* should never get here */
|
|
pg_unreachable();
|
|
}
|
|
|
|
/* ----------------
|
|
* EndCommand - clean up the destination at end of command
|
|
* ----------------
|
|
*/
|
|
void
|
|
EndCommand(const QueryCompletion *qc, CommandDest dest, bool force_undecorated_output)
|
|
{
|
|
char completionTag[COMPLETION_TAG_BUFSIZE];
|
|
CommandTag tag;
|
|
const char *tagname;
|
|
|
|
switch (dest)
|
|
{
|
|
case DestRemote:
|
|
case DestRemoteExecute:
|
|
case DestRemoteSimple:
|
|
|
|
/*
|
|
* We assume the tagname is plain ASCII and therefore requires no
|
|
* encoding conversion.
|
|
*
|
|
* We no longer display LastOid, but to preserve the wire
|
|
* protocol, we write InvalidOid where the LastOid used to be
|
|
* written.
|
|
*
|
|
* All cases where LastOid was written also write nprocessed
|
|
* count, so just Assert that rather than having an extra test.
|
|
*/
|
|
tag = qc->commandTag;
|
|
tagname = GetCommandTagName(tag);
|
|
|
|
if (command_tag_display_rowcount(tag) && !force_undecorated_output)
|
|
snprintf(completionTag, COMPLETION_TAG_BUFSIZE,
|
|
tag == CMDTAG_INSERT ?
|
|
"%s 0 " UINT64_FORMAT : "%s " UINT64_FORMAT,
|
|
tagname, qc->nprocessed);
|
|
else
|
|
snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s", tagname);
|
|
pq_putmessage('C', completionTag, strlen(completionTag) + 1);
|
|
|
|
case DestNone:
|
|
case DestDebug:
|
|
case DestSPI:
|
|
case DestTuplestore:
|
|
case DestIntoRel:
|
|
case DestCopyOut:
|
|
case DestSQLFunction:
|
|
case DestTransientRel:
|
|
case DestTupleQueue:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* ----------------
|
|
* NullCommand - tell dest that an empty query string was recognized
|
|
*
|
|
* 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
|
|
* 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.
|
|
* ----------------
|
|
*/
|
|
void
|
|
NullCommand(CommandDest dest)
|
|
{
|
|
switch (dest)
|
|
{
|
|
case DestRemote:
|
|
case DestRemoteExecute:
|
|
case DestRemoteSimple:
|
|
|
|
/*
|
|
* tell the fe that we saw an empty query string. In protocols
|
|
* before 3.0 this has a useless empty-string message body.
|
|
*/
|
|
if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
|
|
pq_putemptymessage('I');
|
|
else
|
|
pq_putmessage('I', "", 1);
|
|
break;
|
|
|
|
case DestNone:
|
|
case DestDebug:
|
|
case DestSPI:
|
|
case DestTuplestore:
|
|
case DestIntoRel:
|
|
case DestCopyOut:
|
|
case DestSQLFunction:
|
|
case DestTransientRel:
|
|
case DestTupleQueue:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* ----------------
|
|
* ReadyForQuery - tell dest that we are ready for a new query
|
|
*
|
|
* The ReadyForQuery message is sent so that the FE can tell when
|
|
* we are done processing a query string.
|
|
* In versions 3.0 and up, it also carries a transaction state indicator.
|
|
*
|
|
* 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)
|
|
{
|
|
switch (dest)
|
|
{
|
|
case DestRemote:
|
|
case DestRemoteExecute:
|
|
case DestRemoteSimple:
|
|
if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 3)
|
|
{
|
|
StringInfoData buf;
|
|
|
|
pq_beginmessage(&buf, 'Z');
|
|
pq_sendbyte(&buf, TransactionBlockStatusCode());
|
|
pq_endmessage(&buf);
|
|
}
|
|
else
|
|
pq_putemptymessage('Z');
|
|
/* Flush output at end of cycle in any case. */
|
|
pq_flush();
|
|
break;
|
|
|
|
case DestNone:
|
|
case DestDebug:
|
|
case DestSPI:
|
|
case DestTuplestore:
|
|
case DestIntoRel:
|
|
case DestCopyOut:
|
|
case DestSQLFunction:
|
|
case DestTransientRel:
|
|
case DestTupleQueue:
|
|
break;
|
|
}
|
|
}
|