postgres.c

来自「PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统」· C语言 代码 · 共 2,390 行 · 第 1/5 页

		(!IsTransactionExitStmtList(pstmt->query_list) ||
		 numParams != 0))
		ereport(ERROR,
				(errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
				 errmsg("current transaction is aborted, "
						"commands ignored until end of transaction block")));

	/*
	 * Create the portal.  Allow silent replacement of an existing portal only
	 * if the unnamed portal is specified.
	 */
	if (portal_name[0] == '\0')
		portal = CreatePortal(portal_name, true, true);
	else
		portal = CreatePortal(portal_name, false, false);

	/* We need to output the parameter values someday */
	if (log_statement == LOGSTMT_ALL)
		ereport(LOG,
				(errmsg("statement: <BIND> %s", portal_name)));

	/*
	 * Fetch parameters, if any, and store in the portal's memory context.
	 */
	if (numParams > 0)
	{
		ListCell   *l;
		MemoryContext oldContext;

		oldContext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));

		params = (ParamListInfo)
			palloc0((numParams + 1) * sizeof(ParamListInfoData));

		i = 0;
		foreach(l, pstmt->argtype_list)
		{
			Oid			ptype = lfirst_oid(l);
			int32		plength;
			bool		isNull;

			plength = pq_getmsgint(input_message, 4);
			isNull = (plength == -1);

			if (!isNull)
			{
				const char *pvalue = pq_getmsgbytes(input_message, plength);
				int16		pformat;
				StringInfoData pbuf;
				char		csave;

				if (numPFormats > 1)
					pformat = pformats[i];
				else if (numPFormats > 0)
					pformat = pformats[0];
				else
					pformat = 0;	/* default = text */

				/*
				 * Rather than copying data around, we just set up a phony
				 * StringInfo pointing to the correct portion of the message
				 * buffer.	We assume we can scribble on the message buffer so
				 * as to maintain the convention that StringInfos have a
				 * trailing null.  This is grotty but is a big win when
				 * dealing with very large parameter strings.
				 */
				pbuf.data = (char *) pvalue;
				pbuf.maxlen = plength + 1;
				pbuf.len = plength;
				pbuf.cursor = 0;

				csave = pbuf.data[plength];
				pbuf.data[plength] = '\0';

				if (pformat == 0)
				{
					Oid			typinput;
					Oid			typioparam;
					char	   *pstring;

					getTypeInputInfo(ptype, &typinput, &typioparam);

					/*
					 * We have to do encoding conversion before calling the
					 * typinput routine.
					 */
					pstring = pg_client_to_server(pbuf.data, plength);
					params[i].value =
						OidFunctionCall3(typinput,
										 CStringGetDatum(pstring),
										 ObjectIdGetDatum(typioparam),
										 Int32GetDatum(-1));
					/* Free result of encoding conversion, if any */
					if (pstring != pbuf.data)
						pfree(pstring);
				}
				else if (pformat == 1)
				{
					Oid			typreceive;
					Oid			typioparam;

					/*
					 * Call the parameter type's binary input converter
					 */
					getTypeBinaryInputInfo(ptype, &typreceive, &typioparam);

					params[i].value =
						OidFunctionCall3(typreceive,
										 PointerGetDatum(&pbuf),
										 ObjectIdGetDatum(typioparam),
										 Int32GetDatum(-1));

					/* Trouble if it didn't eat the whole buffer */
					if (pbuf.cursor != pbuf.len)
						ereport(ERROR,
							 (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
							  errmsg("incorrect binary data format in bind parameter %d",
									 i + 1)));
				}
				else
				{
					ereport(ERROR,
							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
							 errmsg("unsupported format code: %d",
									pformat)));
				}

				/* Restore message buffer contents */
				pbuf.data[plength] = csave;
			}

			params[i].kind = PARAM_NUM;
			params[i].id = i + 1;
			params[i].ptype = ptype;
			params[i].isnull = isNull;

			i++;
		}

		params[i].kind = PARAM_INVALID;

		MemoryContextSwitchTo(oldContext);
	}
	else
		params = NULL;

	/* Get the result format codes */
	numRFormats = pq_getmsgint(input_message, 2);
	if (numRFormats > 0)
	{
		rformats = (int16 *) palloc(numRFormats * sizeof(int16));
		for (i = 0; i < numRFormats; i++)
			rformats[i] = pq_getmsgint(input_message, 2);
	}

	pq_getmsgend(input_message);

	/*
	 * If we didn't plan the query before, do it now.  This allows the planner
	 * to make use of the concrete parameter values we now have.
	 *
	 * This happens only for unnamed statements, and so switching into the
	 * statement context for planning is correct (see notes in
	 * exec_parse_message).
	 */
	if (pstmt->plan_list == NIL && pstmt->query_list != NIL)
	{
		MemoryContext oldContext = MemoryContextSwitchTo(pstmt->context);

		pstmt->plan_list = pg_plan_queries(pstmt->query_list, params, true);
		MemoryContextSwitchTo(oldContext);
	}

	/*
	 * Define portal and start execution.
	 */
	PortalDefineQuery(portal,
					  pstmt->query_string,
					  pstmt->commandTag,
					  pstmt->query_list,
					  pstmt->plan_list,
					  pstmt->context);

	PortalStart(portal, params, InvalidSnapshot);

	/*
	 * Apply the result format requests to the portal.
	 */
	PortalSetResultFormat(portal, numRFormats, rformats);

	/*
	 * Send BindComplete.
	 */
	if (whereToSendOutput == DestRemote)
		pq_putemptymessage('2');
}

/*
 * exec_execute_message
 *
 * Process an "Execute" message for a portal
 */
static void
exec_execute_message(const char *portal_name, long max_rows)
{
	CommandDest dest;
	DestReceiver *receiver;
	Portal		portal;
	bool		completed;
	char		completionTag[COMPLETION_TAG_BUFSIZE];
	struct timeval start_t,
				stop_t;
	bool		save_log_duration = log_duration;
	int			save_log_min_duration_statement = log_min_duration_statement;
	bool		save_log_statement_stats = log_statement_stats;
	bool		execute_is_fetch = false;

	/* Adjust destination to tell printtup.c what to do */
	dest = whereToSendOutput;
	if (dest == DestRemote)
		dest = DestRemoteExecute;

	portal = GetPortalByName(portal_name);
	if (!PortalIsValid(portal))
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_CURSOR),
				 errmsg("portal \"%s\" does not exist", portal_name)));

	/*
	 * If we re-issue an Execute protocol request against an existing portal,
	 * then we are only fetching more rows rather than completely re-executing
	 * the query from the start. atStart is never reset for a v3 portal, so we
	 * are safe to use this check.
	 */
	if (!portal->atStart)
		execute_is_fetch = true;

	/*
	 * If the original query was a null string, just return
	 * EmptyQueryResponse.
	 */
	if (portal->commandTag == NULL)
	{
		Assert(portal->parseTrees == NIL);
		NullCommand(dest);
		return;
	}

	/* Should we display the portal names here? */
	if (execute_is_fetch)
	{
		debug_query_string = "fetch message";
		pgstat_report_activity("<FETCH>");
	}
	else if (portal->sourceText)
	{
		debug_query_string = portal->sourceText;
		pgstat_report_activity(portal->sourceText);
	}
	else
	{
		debug_query_string = "execute message";
		pgstat_report_activity("<EXECUTE>");
	}

	set_ps_display(portal->commandTag);

	/*
	 * We use save_log_* so "SET log_duration = true"  and "SET
	 * log_min_duration_statement = true" don't report incorrect time because
	 * gettimeofday() wasn't called. Similarly, log_statement_stats has to be
	 * captured once.
	 */
	if (save_log_duration || save_log_min_duration_statement != -1)
		gettimeofday(&start_t, NULL);

	if (save_log_statement_stats)
		ResetUsage();

	if (log_statement == LOGSTMT_ALL)
		/* We have the portal, so output the source query. */
		ereport(LOG,
				(errmsg("statement: %sEXECUTE %s  [PREPARE:  %s]",
						(execute_is_fetch) ? "FETCH from " : "",
						(*portal_name != '\0') ? portal_name : "<unnamed>",
						portal->sourceText ? portal->sourceText : "")));

	BeginCommand(portal->commandTag, dest);

	/*
	 * Create dest receiver in MessageContext (we don't want it in transaction
	 * context, because that may get deleted if portal contains VACUUM).
	 */
	receiver = CreateDestReceiver(dest, portal);

	/*
	 * Ensure we are in a transaction command (this should normally be the
	 * case already due to prior BIND).
	 */
	start_xact_command();

	/*
	 * If we are in aborted transaction state, the only portals we can
	 * actually run are those containing COMMIT or ROLLBACK commands.
	 */
	if (IsAbortedTransactionBlockState() &&
		!IsTransactionExitStmtList(portal->parseTrees))
		ereport(ERROR,
				(errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
				 errmsg("current transaction is aborted, "
						"commands ignored until end of transaction block")));

	/* Check for cancel signal before we start execution */
	CHECK_FOR_INTERRUPTS();

	/*
	 * Okay to run the portal.
	 */
	if (max_rows <= 0)
		max_rows = FETCH_ALL;

	completed = PortalRun(portal,
						  max_rows,
						  receiver,
						  receiver,
						  completionTag);

	(*receiver->rDestroy) (receiver);

	if (completed)
	{
		if (IsTransactionStmtList(portal->parseTrees))
		{
			/*
			 * 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
		{
			/*
			 * We need a CommandCounterIncrement after every query, except
			 * those that start or end a transaction block.
			 */
			CommandCounterIncrement();
		}

		/* Send appropriate CommandComplete to client */
		EndCommand(completionTag, dest);
	}
	else
	{
		/* Portal run not complete, so send PortalSuspended */
		if (whereToSendOutput == DestRemote)
			pq_putemptymessage('s');
	}

	/*
	 * Combine processing here as we need to calculate the query duration in
	 * both instances.
	 */
	if (save_log_duration || save_log_min_duration_statement != -1)
	{
		long		usecs;

		gettimeofday(&stop_t, NULL);
		if (stop_t.tv_usec < start_t.tv_usec)
		{
			stop_t.tv_sec--;
			stop_t.tv_usec += 1000000;
		}
		usecs = (long) (stop_t.tv_sec - start_t.tv_sec) * 1000000 +
			(long) (stop_t.tv_usec - start_t.tv_usec);

		/* Only print duration if we previously printed the statement. */
		if (log_statement == LOGSTMT_ALL && save_log_duration)
			ereport(LOG,
					(errmsg("duration: %ld.%03ld ms",
							(long) ((stop_t.tv_sec - start_t.tv_sec) * 1000 +
								  (stop_t.tv_usec - start_t.tv_usec) / 1000),
						 (long) (stop_t.tv_usec - start_t.tv_usec) % 1000)));

		/*
		 * Output a duration_statement to the log if the query has exceeded
		 * the min duration, or if we are to print all durations.
		 */
		if (save_log_min_duration_statement == 0 ||
			(save_log_min_duration_statement > 0 &&
			 usecs >= save_log_min_duration_statement * 1000))
			ereport(LOG,
					(errmsg("duration: %ld.%03ld ms  statement: %sEXECUTE %s  [PREPARE:  %s]",
							(long) ((stop_t.tv_sec - start_t.tv_sec) * 1000 +
								  (stop_t.tv_usec - start_t.tv_usec) / 1000),
							(long) (stop_t.tv_usec - start_t.tv_usec) % 1000,
							(execute_is_fetch) ? "FETCH from " : "",
						  (*portal_name != '\0') ? portal_name : "<unnamed>",
							portal->sourceText ? portal->sourceText : "")));
	}

	if (save_log_statement_stats)
		ShowUsage("QUERY STATISTICS");

	debug_query_string = NULL;
}

/*
 * exec_describe_statement_message
 *
 * Process a "Describe" message for a prepared statement
 */
static void
exec_describe_statement_message(const char *stmt_name)
{
	PreparedStatement *pstmt;
	TupleDesc	tupdesc;
	ListCell   *l;
	StringInfoData buf;

	/*
	 * Start up a transaction command. (Note that this will normally change
	 * current memory context.) Nothing happens if we are already in one.
	 */
	start_xact_command();

	/* Switch back to message context */
	MemoryContextSwitchTo(MessageContext);

	/* Find prepared statement */
	if (stmt_name[0] != '\0')
		pstmt = FetchPreparedStatement(stmt_name, true);
	else
	{
		/* special-case the unnamed statement */
		pstmt = unnamed_stmt_pstmt;
		if (!pstmt)
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_PSTATEMENT),
					 errmsg("unnamed prepared statement does not exist")));
	}

	/*
	 * If we are in aborted transaction state, we can't safely create a result
	 * tupledesc, because that needs catalog accesses.  Hence, refuse to
	 * Describe statements that return data.  (We shouldn't just refuse all
	 * Describes, since that might break the ability of some clients to issue
	 * COMMIT or ROLLBACK commands, if they use code that blindly Describes
	 * whatever it does.)  We can Describe parameters without doing anything
	 * dangerous, so we don't restrict that.
	 */
	if (IsAbortedTransactionBlockState() &&
		PreparedStatementReturnsTuples(pstmt))
		ereport(ERROR,
				(errcode(ERRCODE_IN_FAILED_SQL_TRANSACTION),
				 errmsg("current transaction is aborted, "
						"commands ignored until end of transaction block")));

	if (whereToSendOutput != DestRemote)
		return;					/* can't actually do anything... */

	/*
	 * First describe the parameters...
	 */
	pq_beginmessage(&buf, 't'); /* parameter description message type */
	pq_sendint(&buf, list_length(pstmt->argtype_list), 2);

	foreach(l, pstmt->argtype_list)
	{
		Oid			ptype = lfirst_oid(l);

		pq_sendint(&buf, (int) ptype, 4);
	}
	pq_endmessage(&buf);

	/*
	 * Next send RowDescription or NoData to describe the result...
	 */
	tupdesc = FetchPreparedStatementResultDesc(pstmt);