libpq_rowproc_20120216.patch

diff --git a/src/interfaces/libpq/#fe-protocol3.c# b/src/interfaces/libpq/#fe-protocol3.c#
new file mode 100644
index 0000000..8b7eed2
--- /dev/null
+++ b/src/interfaces/libpq/#fe-protocol3.c#
@@ -0,0 +1,1967 @@
+/*-------------------------------------------------------------------------
+ *
+ * fe-protocol3.c
+ *	  functions that are specific to frontend/backend protocol version 3
+ *
+ * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/interfaces/libpq/fe-protocol3.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <ctype.h>
+#include <fcntl.h>
+
+#include "libpq-fe.h"
+#include "libpq-int.h"
+
+#include "mb/pg_wchar.h"
+
+#ifdef WIN32
+#include "win32.h"
+#else
+#include <unistd.h>
+#include <netinet/in.h>
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+#include <arpa/inet.h>
+#endif
+
+
+/*
+ * This macro lists the backend message types that could be "long" (more
+ * than a couple of kilobytes).
+ */
+#define VALID_LONG_MESSAGE_TYPE(id) \
+	((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \
+	 (id) == 'E' || (id) == 'N' || (id) == 'A')
+
+
+static void handleSyncLoss(PGconn *conn, char id, int msgLength);
+static int	getRowDescriptions(PGconn *conn);
+static int	getParamDescriptions(PGconn *conn);
+static int	getAnotherTuple(PGconn *conn, int msgLength);
+static int	getParameterStatus(PGconn *conn);
+static int	getNotify(PGconn *conn);
+static int	getCopyStart(PGconn *conn, ExecStatusType copytype);
+static int	getReadyForQuery(PGconn *conn);
+static void reportErrorPosition(PQExpBuffer msg, const char *query,
+					int loc, int encoding);
+static int build_startup_packet(const PGconn *conn, char *packet,
+					 const PQEnvironmentOption *options);
+
+
+/*
+ * parseInput: if appropriate, parse input data from backend
+ * until input is exhausted or a stopping state is reached.
+ * Note that this function will NOT attempt to read more data from the backend.
+ */
+void
+pqParseInput3(PGconn *conn)
+{
+	char		id;
+	int			msgLength;
+	int			avail;
+
+	/*
+	 * Loop to parse successive complete messages available in the buffer.
+	 */
+	for (;;)
+	{
+		/*
+		 * Try to read a message.  First get the type code and length. Return
+		 * if not enough data.
+		 */
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			return;
+		if (pqGetInt(&msgLength, 4, conn))
+			return;
+
+		/*
+		 * Try to validate message type/length here.  A length less than 4 is
+		 * definitely broken.  Large lengths should only be believed for a few
+		 * message types.
+		 */
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return;
+		}
+		if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return;
+		}
+
+		/*
+		 * Can't process if message body isn't all here yet.
+		 */
+		msgLength -= 4;
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength)
+		{
+			/*
+			 * Before returning, enlarge the input buffer if needed to hold
+			 * the whole message.  This is better than leaving it to
+			 * pqReadData because we can avoid multiple cycles of realloc()
+			 * when the message is large; also, we can implement a reasonable
+			 * recovery strategy if we are unable to make the buffer big
+			 * enough.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+			}
+			return;
+		}
+
+		/*
+		 * NOTIFY and NOTICE messages can happen in any state; always process
+		 * them right away.
+		 *
+		 * Most other messages should only be processed while in BUSY state.
+		 * (In particular, in READY state we hold off further parsing until
+		 * the application collects the current PGresult.)
+		 *
+		 * However, if the state is IDLE then we got trouble; we need to deal
+		 * with the unexpected message somehow.
+		 *
+		 * ParameterStatus ('S') messages are a special case: in IDLE state we
+		 * must process 'em (this case could happen if a new value was adopted
+		 * from config file due to SIGHUP), but otherwise we hold off until
+		 * BUSY state.
+		 */
+		if (id == 'A')
+		{
+			if (getNotify(conn))
+				return;
+		}
+		else if (id == 'N')
+		{
+			if (pqGetErrorNotice3(conn, false))
+				return;
+		}
+		else if (conn->asyncStatus != PGASYNC_BUSY)
+		{
+			/* If not IDLE state, just wait ... */
+			if (conn->asyncStatus != PGASYNC_IDLE)
+				return;
+
+			/*
+			 * Unexpected message in IDLE state; need to recover somehow.
+			 * ERROR messages are displayed using the notice processor;
+			 * ParameterStatus is handled normally; anything else is just
+			 * dropped on the floor after displaying a suitable warning
+			 * notice.	(An ERROR is very possibly the backend telling us why
+			 * it is about to close the connection, so we don't want to just
+			 * discard it...)
+			 */
+			if (id == 'E')
+			{
+				if (pqGetErrorNotice3(conn, false /* treat as notice */ ))
+					return;
+			}
+			else if (id == 'S')
+			{
+				if (getParameterStatus(conn))
+					return;
+			}
+			else
+			{
+				pqInternalNotice(&conn->noticeHooks,
+						"message type 0x%02x arrived from server while idle",
+								 id);
+				/* Discard the unexpected message */
+				conn->inCursor += msgLength;
+			}
+		}
+		else
+		{
+			/*
+			 * In BUSY state, we can process everything.
+			 */
+			switch (id)
+			{
+				case 'C':		/* command complete */
+					if (pqGets(&conn->workBuffer, conn))
+						return;
+					if (conn->result == NULL)
+					{
+						conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_COMMAND_OK);
+						if (!conn->result)
+							return;
+					}
+					strncpy(conn->result->cmdStatus, conn->workBuffer.data,
+							CMDSTATUS_LEN);
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case 'E':		/* error return */
+					if (pqGetErrorNotice3(conn, true))
+						return;
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case 'Z':		/* backend is ready for new query */
+					if (getReadyForQuery(conn))
+						return;
+					conn->asyncStatus = PGASYNC_IDLE;
+					break;
+				case 'I':		/* empty query */
+					if (conn->result == NULL)
+					{
+						conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_EMPTY_QUERY);
+						if (!conn->result)
+							return;
+					}
+					conn->asyncStatus = PGASYNC_READY;
+					break;
+				case '1':		/* Parse Complete */
+					/* If we're doing PQprepare, we're done; else ignore */
+					if (conn->queryclass == PGQUERY_PREPARE)
+					{
+						if (conn->result == NULL)
+						{
+							conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_COMMAND_OK);
+							if (!conn->result)
+								return;
+						}
+						conn->asyncStatus = PGASYNC_READY;
+					}
+					break;
+				case '2':		/* Bind Complete */
+				case '3':		/* Close Complete */
+					/* Nothing to do for these message types */
+					break;
+				case 'S':		/* parameter status */
+					if (getParameterStatus(conn))
+						return;
+					break;
+				case 'K':		/* secret key data from the backend */
+
+					/*
+					 * This is expected only during backend startup, but it's
+					 * just as easy to handle it as part of the main loop.
+					 * Save the data and continue processing.
+					 */
+					if (pqGetInt(&(conn->be_pid), 4, conn))
+						return;
+					if (pqGetInt(&(conn->be_key), 4, conn))
+						return;
+					break;
+				case 'T':		/* Row Description */
+					if (conn->result == NULL ||
+						conn->queryclass == PGQUERY_DESCRIBE)
+					{
+						/* First 'T' in a query sequence */
+						if (getRowDescriptions(conn))
+							return;
+
+						/*
+						 * If we're doing a Describe, we're ready to pass the
+						 * result back to the client.
+						 */
+						if (conn->queryclass == PGQUERY_DESCRIBE)
+							conn->asyncStatus = PGASYNC_READY;
+					}
+					else
+					{
+						/*
+						 * A new 'T' message is treated as the start of
+						 * another PGresult.  (It is not clear that this is
+						 * really possible with the current backend.) We stop
+						 * parsing until the application accepts the current
+						 * result.
+						 */
+						conn->asyncStatus = PGASYNC_READY;
+						return;
+					}
+					break;
+				case 'n':		/* No Data */
+
+					/*
+					 * NoData indicates that we will not be seeing a
+					 * RowDescription message because the statement or portal
+					 * inquired about doesn't return rows.
+					 *
+					 * If we're doing a Describe, we have to pass something
+					 * back to the client, so set up a COMMAND_OK result,
+					 * instead of TUPLES_OK.  Otherwise we can just ignore
+					 * this message.
+					 */
+					if (conn->queryclass == PGQUERY_DESCRIBE)
+					{
+						if (conn->result == NULL)
+						{
+							conn->result = PQmakeEmptyPGresult(conn,
+														   PGRES_COMMAND_OK);
+							if (!conn->result)
+								return;
+						}
+						conn->asyncStatus = PGASYNC_READY;
+					}
+					break;
+				case 't':		/* Parameter Description */
+					if (getParamDescriptions(conn))
+						return;
+					break;
+				case 'D':		/* Data Row */
+					if (conn->result != NULL &&
+						conn->result->resultStatus == PGRES_TUPLES_OK)
+					{
+						/* Read another tuple of a normal query response */
+						if (getAnotherTuple(conn, msgLength))
+							return;
+					}
+					else if (conn->result != NULL &&
+							 conn->result->resultStatus == PGRES_FATAL_ERROR)
+					{
+						/*
+						 * We've already choked for some reason.  Just discard
+						 * tuples till we get to the end of the query.
+						 */
+						conn->inCursor += msgLength;
+					}
+					else
+					{
+						/* Set up to report error at end of query */
+						printfPQExpBuffer(&conn->errorMessage,
+										  libpq_gettext("server sent data (\"D\" message) without prior row description (\"T\" message)\n"));
+						pqSaveErrorResult(conn);
+						/* Discard the unexpected message */
+						conn->inCursor += msgLength;
+					}
+					break;
+				case 'G':		/* Start Copy In */
+					if (getCopyStart(conn, PGRES_COPY_IN))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_IN;
+					break;
+				case 'H':		/* Start Copy Out */
+					if (getCopyStart(conn, PGRES_COPY_OUT))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_OUT;
+					conn->copy_already_done = 0;
+					break;
+				case 'W':		/* Start Copy Both */
+					if (getCopyStart(conn, PGRES_COPY_BOTH))
+						return;
+					conn->asyncStatus = PGASYNC_COPY_BOTH;
+					conn->copy_already_done = 0;
+					break;
+				case 'd':		/* Copy Data */
+
+					/*
+					 * If we see Copy Data, just silently drop it.	This would
+					 * only occur if application exits COPY OUT mode too
+					 * early.
+					 */
+					conn->inCursor += msgLength;
+					break;
+				case 'c':		/* Copy Done */
+
+					/*
+					 * If we see Copy Done, just silently drop it.	This is
+					 * the normal case during PQendcopy.  We will keep
+					 * swallowing data, expecting to see command-complete for
+					 * the COPY command.
+					 */
+					break;
+				default:
+					printfPQExpBuffer(&conn->errorMessage,
+									  libpq_gettext(
+													"unexpected response from server; first received character was \"%c\"\n"),
+									  id);
+					/* build an error result holding the error message */
+					pqSaveErrorResult(conn);
+					/* not sure if we will see more, so go to ready state */
+					conn->asyncStatus = PGASYNC_READY;
+					/* Discard the unexpected message */
+					conn->inCursor += msgLength;
+					break;
+			}					/* switch on protocol character */
+		}
+		/* Successfully consumed this message */
+		if (conn->inCursor == conn->inStart + 5 + msgLength)
+		{
+			/* Normal case: parsing agrees with specified length */
+			conn->inStart = conn->inCursor;
+		}
+		else
+		{
+			/* Trouble --- report it */
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("message contents do not agree with length in message type \"%c\"\n"),
+							  id);
+			/* build an error result holding the error message */
+			pqSaveErrorResult(conn);
+			conn->asyncStatus = PGASYNC_READY;
+			/* trust the specified message length as what to skip */
+			conn->inStart += 5 + msgLength;
+		}
+	}
+}
+
+/*
+ * handleSyncLoss: clean up after loss of message-boundary sync
+ *
+ * There isn't really a lot we can do here except abandon the connection.
+ */
+static void
+handleSyncLoss(PGconn *conn, char id, int msgLength)
+{
+	printfPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext(
+	"lost synchronization with server: got message type \"%c\", length %d\n"),
+					  id, msgLength);
+	/* build an error result holding the error message */
+	pqSaveErrorResult(conn);
+	conn->asyncStatus = PGASYNC_READY;	/* drop out of GetResult wait loop */
+
+	pqsecure_close(conn);
+	closesocket(conn->sock);
+	conn->sock = -1;
+	conn->status = CONNECTION_BAD;		/* No more connection to backend */
+}
+
+/*
+ * parseInput subroutine to read a 'T' (row descriptions) message.
+ * We'll build a new PGresult structure (unless called for a Describe
+ * command for a prepared statement) containing the attribute data.
+ * Returns: 0 if completed message, EOF if not enough data yet.
+ *
+ * Note that if we run out of data, we have to release the partially
+ * constructed PGresult, and rebuild it again next time.  Fortunately,
+ * that shouldn't happen often, since 'T' messages usually fit in a packet.
+ */
+static int
+getRowDescriptions(PGconn *conn)
+{
+	PGresult   *result;
+	int			nfields;
+	int			i;
+
+	/*
+	 * When doing Describe for a prepared statement, there'll already be a
+	 * PGresult created by getParamDescriptions, and we should fill data into
+	 * that.  Otherwise, create a new, empty PGresult.
+	 */
+	if (conn->queryclass == PGQUERY_DESCRIBE)
+	{
+		if (conn->result)
+			result = conn->result;
+		else
+			result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+	}
+	else
+		result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
+	if (!result)
+		goto failure;
+
+	/* parseInput already read the 'T' label and message length. */
+	/* the next two bytes are the number of fields */
+	if (pqGetInt(&(result->numAttributes), 2, conn))
+		goto failure;
+	nfields = result->numAttributes;
+
+	/* allocate space for the attribute descriptors */
+	if (nfields > 0)
+	{
+		result->attDescs = (PGresAttDesc *)
+			pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
+		if (!result->attDescs)
+			goto failure;
+		MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
+	}
+
+	/* result->binary is true only if ALL columns are binary */
+	result->binary = (nfields > 0) ? 1 : 0;
+
+	/* get type info */
+	for (i = 0; i < nfields; i++)
+	{
+		int			tableid;
+		int			columnid;
+		int			typid;
+		int			typlen;
+		int			atttypmod;
+		int			format;
+
+		if (pqGets(&conn->workBuffer, conn) ||
+			pqGetInt(&tableid, 4, conn) ||
+			pqGetInt(&columnid, 2, conn) ||
+			pqGetInt(&typid, 4, conn) ||
+			pqGetInt(&typlen, 2, conn) ||
+			pqGetInt(&atttypmod, 4, conn) ||
+			pqGetInt(&format, 2, conn))
+		{
+			goto failure;
+		}
+
+		/*
+		 * Since pqGetInt treats 2-byte integers as unsigned, we need to
+		 * coerce these results to signed form.
+		 */
+		columnid = (int) ((int16) columnid);
+		typlen = (int) ((int16) typlen);
+		format = (int) ((int16) format);
+
+		result->attDescs[i].name = pqResultStrdup(result,
+												  conn->workBuffer.data);
+		if (!result->attDescs[i].name)
+			goto failure;
+		result->attDescs[i].tableid = tableid;
+		result->attDescs[i].columnid = columnid;
+		result->attDescs[i].format = format;
+		result->attDescs[i].typid = typid;
+		result->attDescs[i].typlen = typlen;
+		result->attDescs[i].atttypmod = atttypmod;
+
+		if (format != 1)
+			result->binary = 0;
+	}
+
+	/* Success! */
+	conn->result = result;
+	return 0;
+
+failure:
+
+	/*
+	 * Discard incomplete result, unless it's from getParamDescriptions.
+	 *
+	 * Note that if we hit a bufferload boundary while handling the
+	 * describe-statement case, we'll forget any PGresult space we just
+	 * allocated, and then reallocate it on next try.  This will bloat the
+	 * PGresult a little bit but the space will be freed at PQclear, so it
+	 * doesn't seem worth trying to be smarter.
+	 */
+	if (result != conn->result)
+		PQclear(result);
+	return EOF;
+}
+
+/*
+ * parseInput subroutine to read a 't' (ParameterDescription) message.
+ * We'll build a new PGresult structure containing the parameter data.
+ * Returns: 0 if completed message, EOF if not enough data yet.
+ *
+ * Note that if we run out of data, we have to release the partially
+ * constructed PGresult, and rebuild it again next time.  Fortunately,
+ * that shouldn't happen often, since 't' messages usually fit in a packet.
+ */
+static int
+getParamDescriptions(PGconn *conn)
+{
+	PGresult   *result;
+	int			nparams;
+	int			i;
+
+	result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
+	if (!result)
+		goto failure;
+
+	/* parseInput already read the 't' label and message length. */
+	/* the next two bytes are the number of parameters */
+	if (pqGetInt(&(result->numParameters), 2, conn))
+		goto failure;
+	nparams = result->numParameters;
+
+	/* allocate space for the parameter descriptors */
+	if (nparams > 0)
+	{
+		result->paramDescs = (PGresParamDesc *)
+			pqResultAlloc(result, nparams * sizeof(PGresParamDesc), TRUE);
+		if (!result->paramDescs)
+			goto failure;
+		MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
+	}
+
+	/* get parameter info */
+	for (i = 0; i < nparams; i++)
+	{
+		int			typid;
+
+		if (pqGetInt(&typid, 4, conn))
+			goto failure;
+		result->paramDescs[i].typid = typid;
+	}
+
+	/* Success! */
+	conn->result = result;
+	return 0;
+
+failure:
+	PQclear(result);
+	return EOF;
+}
+
+/*
+ * parseInput subroutine to read a 'D' (row data) message.
+ * We add another tuple to the existing PGresult structure.
+ * Returns: 0 if completed message, EOF if error or not enough data yet.
+ *
+ * Note that if we run out of data, we have to suspend and reprocess
+ * the message after more data is received.  We keep a partially constructed
+ * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ */
+static int
+getAnotherTuple(PGconn *conn, int msgLength)
+{
+	PGresult   *result = conn->result;
+	int			nfields = result->numAttributes;
+	PGrowValue  rowval[result->numAttributes + 1];
+	int			tupnfields;		/* # fields from tuple */
+	int			vlen;			/* length of the current field value */
+	int			i;
+
+	/* Allocate tuple space if first time for this data message */
+	/* Get the field count and make sure it's what we expect */
+	if (pqGetInt(&tupnfields, 2, conn))
+		return EOF;
+
+	if (tupnfields != nfields)
+	{
+		/* Replace partially constructed result with an error result */
+		printfPQExpBuffer(&conn->errorMessage,
+				 libpq_gettext("unexpected field count in \"D\" message\n"));
+		pqSaveErrorResult(conn);
+		/* Discard the failed message by pretending we read it */
+		conn->inCursor = conn->inStart + 5 + msgLength;
+		return 0;
+	}
+
+	/* Scan the fields */
+	for (i = 0; i < nfields; i++)
+	{
+		/* get the value length */
+		if (pqGetInt(&vlen, 4, conn))
+			return EOF;
+		if (vlen == -1)
+			vlen = NULL_LEN;
+		else if (vlen < 0)
+			vlen = 0;
+		
+		/*
+		 * Buffer content may be shifted on reloading additional
+		 * data. So we must set all pointers on every scan.
+		 * 
+		 * rowval[i].value always points to the next address of the
+		 * length field even if the value length is zero or the value
+		 * is NULL for the access safety.
+		 */
+		rowval[i].value = conn->inBuffer + conn->inCursor;
+ 		rowval[i].len = vlen;
+
+		/* Skip to the next length field */
+		if (vlen > 0 && pqSkipnchar(vlen, conn))
+			return EOF;
+	}
+
+	/*
+	 * Set rowval[nfields] for the access safety. We can estimate the
+	 * length of the buffer to store by
+	 *
+     *    rowval[nfields].value - rowval[0].value - 4 * nfields.
+	 */
+	rowval[nfields].value = conn->inBuffer + conn->inCursor;
+	rowval[nfields].len = NULL_LEN;
+
+	/* Success!  Pass the completed row values to rowProcessor */
+	if (!result->rowProcessor(result, result->rowProcessorParam, rowval))
+		goto rowProcessError;
+	
+	/* Free garbage error message. */
+	if (result->rowProcessorErrMes)
+	{
+		free(result->rowProcessorErrMes);
+		result->rowProcessorErrMes = NULL;
+	}
+
+	return 0;
+
+rowProcessError:
+
+	/*
+	 * Replace partially constructed result with an error result. First
+	 * discard the old result to try to win back some memory.
+	 */
+	pqClearAsyncResult(conn);
+	resetPQExpBuffer(&conn->errorMessage);
+
+	/*
+	 * If error message is passed from addTupleFunc, set it into
+	 * PGconn, assume out of memory if not.
+	 */
+	appendPQExpBufferStr(&conn->errorMessage,
+						 libpq_gettext(result->rowProcessorErrMes ?
+									   result->rowProcessorErrMes : 
+									   "out of memory for query result\n"));
+	if (result->rowProcessorErrMes)
+	{
+o		free(result->rowProcessorErrMes);
+		result->rowProcessorErrMes = NULL;
+	}
+	pqSaveErrorResult(conn);
+
+	/* Discard the failed message by pretending we read it */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+	return 0;
+}
+
+
+/*
+ * Attempt to read an Error or Notice response message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'E' or 'N' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ *		 returns EOF if not enough data.
+ */
+int
+pqGetErrorNotice3(PGconn *conn, bool isError)
+{
+	PGresult   *res = NULL;
+	PQExpBufferData workBuf;
+	char		id;
+	const char *val;
+	const char *querytext = NULL;
+	int			querypos = 0;
+
+	/*
+	 * Since the fields might be pretty long, we create a temporary
+	 * PQExpBuffer rather than using conn->workBuffer.	workBuffer is intended
+	 * for stuff that is expected to be short.	We shouldn't use
+	 * conn->errorMessage either, since this might be only a notice.
+	 */
+	initPQExpBuffer(&workBuf);
+
+	/*
+	 * Make a PGresult to hold the accumulated fields.	We temporarily lie
+	 * about the result status, so that PQmakeEmptyPGresult doesn't uselessly
+	 * copy conn->errorMessage.
+	 */
+	res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
+	if (!res)
+		goto fail;
+	res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;
+
+	/*
+	 * Read the fields and save into res.
+	 */
+	for (;;)
+	{
+		if (pqGetc(&id, conn))
+			goto fail;
+		if (id == '\0')
+			break;				/* terminator found */
+		if (pqGets(&workBuf, conn))
+			goto fail;
+		pqSaveMessageField(res, id, workBuf.data);
+	}
+
+	/*
+	 * Now build the "overall" error message for PQresultErrorMessage.
+	 *
+	 * Also, save the SQLSTATE in conn->last_sqlstate.
+	 */
+	resetPQExpBuffer(&workBuf);
+	val = PQresultErrorField(res, PG_DIAG_SEVERITY);
+	if (val)
+		appendPQExpBuffer(&workBuf, "%s:  ", val);
+	val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
+	if (val)
+	{
+		if (strlen(val) < sizeof(conn->last_sqlstate))
+			strcpy(conn->last_sqlstate, val);
+		if (conn->verbosity == PQERRORS_VERBOSE)
+			appendPQExpBuffer(&workBuf, "%s: ", val);
+	}
+	val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
+	if (val)
+		appendPQExpBufferStr(&workBuf, val);
+	val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
+	if (val)
+	{
+		if (conn->verbosity != PQERRORS_TERSE && conn->last_query != NULL)
+		{
+			/* emit position as a syntax cursor display */
+			querytext = conn->last_query;
+			querypos = atoi(val);
+		}
+		else
+		{
+			/* emit position as text addition to primary message */
+			/* translator: %s represents a digit string */
+			appendPQExpBuffer(&workBuf, libpq_gettext(" at character %s"),
+							  val);
+		}
+	}
+	else
+	{
+		val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
+		if (val)
+		{
+			querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+			if (conn->verbosity != PQERRORS_TERSE && querytext != NULL)
+			{
+				/* emit position as a syntax cursor display */
+				querypos = atoi(val);
+			}
+			else
+			{
+				/* emit position as text addition to primary message */
+				/* translator: %s represents a digit string */
+				appendPQExpBuffer(&workBuf, libpq_gettext(" at character %s"),
+								  val);
+			}
+		}
+	}
+	appendPQExpBufferChar(&workBuf, '\n');
+	if (conn->verbosity != PQERRORS_TERSE)
+	{
+		if (querytext && querypos > 0)
+			reportErrorPosition(&workBuf, querytext, querypos,
+								conn->client_encoding);
+		val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
+		if (val)
+			appendPQExpBuffer(&workBuf, libpq_gettext("DETAIL:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
+		if (val)
+			appendPQExpBuffer(&workBuf, libpq_gettext("HINT:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
+		if (val)
+			appendPQExpBuffer(&workBuf, libpq_gettext("QUERY:  %s\n"), val);
+		val = PQresultErrorField(res, PG_DIAG_CONTEXT);
+		if (val)
+			appendPQExpBuffer(&workBuf, libpq_gettext("CONTEXT:  %s\n"), val);
+	}
+	if (conn->verbosity == PQERRORS_VERBOSE)
+	{
+		const char *valf;
+		const char *vall;
+
+		valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE);
+		vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE);
+		val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION);
+		if (val || valf || vall)
+		{
+			appendPQExpBufferStr(&workBuf, libpq_gettext("LOCATION:  "));
+			if (val)
+				appendPQExpBuffer(&workBuf, libpq_gettext("%s, "), val);
+			if (valf && vall)	/* unlikely we'd have just one */
+				appendPQExpBuffer(&workBuf, libpq_gettext("%s:%s"),
+								  valf, vall);
+			appendPQExpBufferChar(&workBuf, '\n');
+		}
+	}
+
+	/*
+	 * Either save error as current async result, or just emit the notice.
+	 */
+	if (isError)
+	{
+		res->errMsg = pqResultStrdup(res, workBuf.data);
+		if (!res->errMsg)
+			goto fail;
+		pqClearAsyncResult(conn);
+		conn->result = res;
+		appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
+	}
+	else
+	{
+		/* We can cheat a little here and not copy the message. */
+		res->errMsg = workBuf.data;
+		if (res->noticeHooks.noticeRec != NULL)
+			(*res->noticeHooks.noticeRec) (res->noticeHooks.noticeRecArg, res);
+		PQclear(res);
+	}
+
+	termPQExpBuffer(&workBuf);
+	return 0;
+
+fail:
+	PQclear(res);
+	termPQExpBuffer(&workBuf);
+	return EOF;
+}
+
+/*
+ * Add an error-location display to the error message under construction.
+ *
+ * The cursor location is measured in logical characters; the query string
+ * is presumed to be in the specified encoding.
+ */
+static void
+reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
+{
+#define DISPLAY_SIZE	60		/* screen width limit, in screen cols */
+#define MIN_RIGHT_CUT	10		/* try to keep this far away from EOL */
+
+	char	   *wquery;
+	int			slen,
+				cno,
+				i,
+			   *qidx,
+			   *scridx,
+				qoffset,
+				scroffset,
+				ibeg,
+				iend,
+				loc_line;
+	bool		mb_encoding,
+				beg_trunc,
+				end_trunc;
+
+	/* Convert loc from 1-based to 0-based; no-op if out of range */
+	loc--;
+	if (loc < 0)
+		return;
+
+	/* Need a writable copy of the query */
+	wquery = strdup(query);
+	if (wquery == NULL)
+		return;					/* fail silently if out of memory */
+
+	/*
+	 * Each character might occupy multiple physical bytes in the string, and
+	 * in some Far Eastern character sets it might take more than one screen
+	 * column as well.	We compute the starting byte offset and starting
+	 * screen column of each logical character, and store these in qidx[] and
+	 * scridx[] respectively.
+	 */
+
+	/* we need a safe allocation size... */
+	slen = strlen(wquery) + 1;
+
+	qidx = (int *) malloc(slen * sizeof(int));
+	if (qidx == NULL)
+	{
+		free(wquery);
+		return;
+	}
+	scridx = (int *) malloc(slen * sizeof(int));
+	if (scridx == NULL)
+	{
+		free(qidx);
+		free(wquery);
+		return;
+	}
+
+	/* We can optimize a bit if it's a single-byte encoding */
+	mb_encoding = (pg_encoding_max_length(encoding) != 1);
+
+	/*
+	 * Within the scanning loop, cno is the current character's logical
+	 * number, qoffset is its offset in wquery, and scroffset is its starting
+	 * logical screen column (all indexed from 0).	"loc" is the logical
+	 * character number of the error location.	We scan to determine loc_line
+	 * (the 1-based line number containing loc) and ibeg/iend (first character
+	 * number and last+1 character number of the line containing loc). Note
+	 * that qidx[] and scridx[] are filled only as far as iend.
+	 */
+	qoffset = 0;
+	scroffset = 0;
+	loc_line = 1;
+	ibeg = 0;
+	iend = -1;					/* -1 means not set yet */
+
+	for (cno = 0; wquery[qoffset] != '\0'; cno++)
+	{
+		char		ch = wquery[qoffset];
+
+		qidx[cno] = qoffset;
+		scridx[cno] = scroffset;
+
+		/*
+		 * Replace tabs with spaces in the writable copy.  (Later we might
+		 * want to think about coping with their variable screen width, but
+		 * not today.)
+		 */
+		if (ch == '\t')
+			wquery[qoffset] = ' ';
+
+		/*
+		 * If end-of-line, count lines and mark positions. Each \r or \n
+		 * counts as a line except when \r \n appear together.
+		 */
+		else if (ch == '\r' || ch == '\n')
+		{
+			if (cno < loc)
+			{
+				if (ch == '\r' ||
+					cno == 0 ||
+					wquery[qidx[cno - 1]] != '\r')
+					loc_line++;
+				/* extract beginning = last line start before loc. */
+				ibeg = cno + 1;
+			}
+			else
+			{
+				/* set extract end. */
+				iend = cno;
+				/* done scanning. */
+				break;
+			}
+		}
+
+		/* Advance */
+		if (mb_encoding)
+		{
+			int			w;
+
+			w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
+			/* treat any non-tab control chars as width 1 */
+			if (w <= 0)
+				w = 1;
+			scroffset += w;
+			qoffset += pg_encoding_mblen(encoding, &wquery[qoffset]);
+		}
+		else
+		{
+			/* We assume wide chars only exist in multibyte encodings */
+			scroffset++;
+			qoffset++;
+		}
+	}
+	/* Fix up if we didn't find an end-of-line after loc */
+	if (iend < 0)
+	{
+		iend = cno;				/* query length in chars, +1 */
+		qidx[iend] = qoffset;
+		scridx[iend] = scroffset;
+	}
+
+	/* Print only if loc is within computed query length */
+	if (loc <= cno)
+	{
+		/* If the line extracted is too long, we truncate it. */
+		beg_trunc = false;
+		end_trunc = false;
+		if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+		{
+			/*
+			 * We first truncate right if it is enough.  This code might be
+			 * off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
+			 * character right there, but that should be okay.
+			 */
+			if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
+			{
+				while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+					iend--;
+				end_trunc = true;
+			}
+			else
+			{
+				/* Truncate right if not too close to loc. */
+				while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
+				{
+					iend--;
+					end_trunc = true;
+				}
+
+				/* Truncate left if still too long. */
+				while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
+				{
+					ibeg++;
+					beg_trunc = true;
+				}
+			}
+		}
+
+		/* truncate working copy at desired endpoint */
+		wquery[qidx[iend]] = '\0';
+
+		/* Begin building the finished message. */
+		i = msg->len;
+		appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
+		if (beg_trunc)
+			appendPQExpBufferStr(msg, "...");
+
+		/*
+		 * While we have the prefix in the msg buffer, compute its screen
+		 * width.
+		 */
+		scroffset = 0;
+		for (; i < msg->len; i += pg_encoding_mblen(encoding, &msg->data[i]))
+		{
+			int			w = pg_encoding_dsplen(encoding, &msg->data[i]);
+
+			if (w <= 0)
+				w = 1;
+			scroffset += w;
+		}
+
+		/* Finish up the LINE message line. */
+		appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
+		if (end_trunc)
+			appendPQExpBufferStr(msg, "...");
+		appendPQExpBufferChar(msg, '\n');
+
+		/* Now emit the cursor marker line. */
+		scroffset += scridx[loc] - scridx[ibeg];
+		for (i = 0; i < scroffset; i++)
+			appendPQExpBufferChar(msg, ' ');
+		appendPQExpBufferChar(msg, '^');
+		appendPQExpBufferChar(msg, '\n');
+	}
+
+	/* Clean up. */
+	free(scridx);
+	free(qidx);
+	free(wquery);
+}
+
+
+/*
+ * Attempt to read a ParameterStatus message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'S' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed message.
+ *		 returns EOF if not enough data.
+ */
+static int
+getParameterStatus(PGconn *conn)
+{
+	PQExpBufferData valueBuf;
+
+	/* Get the parameter name */
+	if (pqGets(&conn->workBuffer, conn))
+		return EOF;
+	/* Get the parameter value (could be large) */
+	initPQExpBuffer(&valueBuf);
+	if (pqGets(&valueBuf, conn))
+	{
+		termPQExpBuffer(&valueBuf);
+		return EOF;
+	}
+	/* And save it */
+	pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data);
+	termPQExpBuffer(&valueBuf);
+	return 0;
+}
+
+
+/*
+ * Attempt to read a Notify response message.
+ * This is possible in several places, so we break it out as a subroutine.
+ * Entry: 'A' message type and length have already been consumed.
+ * Exit: returns 0 if successfully consumed Notify message.
+ *		 returns EOF if not enough data.
+ */
+static int
+getNotify(PGconn *conn)
+{
+	int			be_pid;
+	char	   *svname;
+	int			nmlen;
+	int			extralen;
+	PGnotify   *newNotify;
+
+	if (pqGetInt(&be_pid, 4, conn))
+		return EOF;
+	if (pqGets(&conn->workBuffer, conn))
+		return EOF;
+	/* must save name while getting extra string */
+	svname = strdup(conn->workBuffer.data);
+	if (!svname)
+		return EOF;
+	if (pqGets(&conn->workBuffer, conn))
+	{
+		free(svname);
+		return EOF;
+	}
+
+	/*
+	 * Store the strings right after the PQnotify structure so it can all be
+	 * freed at once.  We don't use NAMEDATALEN because we don't want to tie
+	 * this interface to a specific server name length.
+	 */
+	nmlen = strlen(svname);
+	extralen = strlen(conn->workBuffer.data);
+	newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2);
+	if (newNotify)
+	{
+		newNotify->relname = (char *) newNotify + sizeof(PGnotify);
+		strcpy(newNotify->relname, svname);
+		newNotify->extra = newNotify->relname + nmlen + 1;
+		strcpy(newNotify->extra, conn->workBuffer.data);
+		newNotify->be_pid = be_pid;
+		newNotify->next = NULL;
+		if (conn->notifyTail)
+			conn->notifyTail->next = newNotify;
+		else
+			conn->notifyHead = newNotify;
+		conn->notifyTail = newNotify;
+	}
+
+	free(svname);
+	return 0;
+}
+
+/*
+ * getCopyStart - process CopyInResponse, CopyOutResponse or
+ * CopyBothResponse message
+ *
+ * parseInput already read the message type and length.
+ */
+static int
+getCopyStart(PGconn *conn, ExecStatusType copytype)
+{
+	PGresult   *result;
+	int			nfields;
+	int			i;
+
+	result = PQmakeEmptyPGresult(conn, copytype);
+	if (!result)
+		goto failure;
+
+	if (pqGetc(&conn->copy_is_binary, conn))
+		goto failure;
+	result->binary = conn->copy_is_binary;
+	/* the next two bytes are the number of fields	*/
+	if (pqGetInt(&(result->numAttributes), 2, conn))
+		goto failure;
+	nfields = result->numAttributes;
+
+	/* allocate space for the attribute descriptors */
+	if (nfields > 0)
+	{
+		result->attDescs = (PGresAttDesc *)
+			pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
+		if (!result->attDescs)
+			goto failure;
+		MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
+	}
+
+	for (i = 0; i < nfields; i++)
+	{
+		int			format;
+
+		if (pqGetInt(&format, 2, conn))
+			goto failure;
+
+		/*
+		 * Since pqGetInt treats 2-byte integers as unsigned, we need to
+		 * coerce these results to signed form.
+		 */
+		format = (int) ((int16) format);
+		result->attDescs[i].format = format;
+	}
+
+	/* Success! */
+	conn->result = result;
+	return 0;
+
+failure:
+	PQclear(result);
+	return EOF;
+}
+
+/*
+ * getReadyForQuery - process ReadyForQuery message
+ */
+static int
+getReadyForQuery(PGconn *conn)
+{
+	char		xact_status;
+
+	if (pqGetc(&xact_status, conn))
+		return EOF;
+	switch (xact_status)
+	{
+		case 'I':
+			conn->xactStatus = PQTRANS_IDLE;
+			break;
+		case 'T':
+			conn->xactStatus = PQTRANS_INTRANS;
+			break;
+		case 'E':
+			conn->xactStatus = PQTRANS_INERROR;
+			break;
+		default:
+			conn->xactStatus = PQTRANS_UNKNOWN;
+			break;
+	}
+
+	return 0;
+}
+
+/*
+ * getCopyDataMessage - fetch next CopyData message, process async messages
+ *
+ * Returns length word of CopyData message (> 0), or 0 if no complete
+ * message available, -1 if end of copy, -2 if error.
+ */
+static int
+getCopyDataMessage(PGconn *conn)
+{
+	char		id;
+	int			msgLength;
+	int			avail;
+
+	for (;;)
+	{
+		/*
+		 * Do we have the next input message?  To make life simpler for async
+		 * callers, we keep returning 0 until the next message is fully
+		 * available, even if it is not Copy Data.
+		 */
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			return 0;
+		if (pqGetInt(&msgLength, 4, conn))
+			return 0;
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			return -2;
+		}
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength - 4)
+		{
+			/*
+			 * Before returning, enlarge the input buffer if needed to hold
+			 * the whole message.  See notes in parseInput.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+				return -2;
+			}
+			return 0;
+		}
+
+		/*
+		 * If it's a legitimate async message type, process it.  (NOTIFY
+		 * messages are not currently possible here, but we handle them for
+		 * completeness.)  Otherwise, if it's anything except Copy Data,
+		 * report end-of-copy.
+		 */
+		switch (id)
+		{
+			case 'A':			/* NOTIFY */
+				if (getNotify(conn))
+					return 0;
+				break;
+			case 'N':			/* NOTICE */
+				if (pqGetErrorNotice3(conn, false))
+					return 0;
+				break;
+			case 'S':			/* ParameterStatus */
+				if (getParameterStatus(conn))
+					return 0;
+				break;
+			case 'd':			/* Copy Data, pass it back to caller */
+				return msgLength;
+			default:			/* treat as end of copy */
+				return -1;
+		}
+
+		/* Drop the processed message and loop around for another */
+		conn->inStart = conn->inCursor;
+	}
+}
+
+/*
+ * PQgetCopyData - read a row of data from the backend during COPY OUT
+ * or COPY BOTH
+ *
+ * If successful, sets *buffer to point to a malloc'd row of data, and
+ * returns row length (always > 0) as result.
+ * Returns 0 if no row available yet (only possible if async is true),
+ * -1 if end of copy (consult PQgetResult), or -2 if error (consult
+ * PQerrorMessage).
+ */
+int
+pqGetCopyData3(PGconn *conn, char **buffer, int async)
+{
+	int			msgLength;
+
+	for (;;)
+	{
+		/*
+		 * Collect the next input message.	To make life simpler for async
+		 * callers, we keep returning 0 until the next message is fully
+		 * available, even if it is not Copy Data.
+		 */
+		msgLength = getCopyDataMessage(conn);
+		if (msgLength < 0)
+		{
+			/*
+			 * On end-of-copy, exit COPY_OUT or COPY_BOTH mode and let caller
+			 * read status with PQgetResult().	The normal case is that it's
+			 * Copy Done, but we let parseInput read that.	If error, we
+			 * expect the state was already changed.
+			 */
+			if (msgLength == -1)
+				conn->asyncStatus = PGASYNC_BUSY;
+			return msgLength;	/* end-of-copy or error */
+		}
+		if (msgLength == 0)
+		{
+			/* Don't block if async read requested */
+			if (async)
+				return 0;
+			/* Need to load more data */
+			if (pqWait(TRUE, FALSE, conn) ||
+				pqReadData(conn) < 0)
+				return -2;
+			continue;
+		}
+
+		/*
+		 * Drop zero-length messages (shouldn't happen anyway).  Otherwise
+		 * pass the data back to the caller.
+		 */
+		msgLength -= 4;
+		if (msgLength > 0)
+		{
+			*buffer = (char *) malloc(msgLength + 1);
+			if (*buffer == NULL)
+			{
+				printfPQExpBuffer(&conn->errorMessage,
+								  libpq_gettext("out of memory\n"));
+				return -2;
+			}
+			memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength);
+			(*buffer)[msgLength] = '\0';		/* Add terminating null */
+
+			/* Mark message consumed */
+			conn->inStart = conn->inCursor + msgLength;
+
+			return msgLength;
+		}
+
+		/* Empty, so drop it and loop around for another */
+		conn->inStart = conn->inCursor;
+	}
+}
+
+/*
+ * PQgetline - gets a newline-terminated string from the backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetline3(PGconn *conn, char *s, int maxlen)
+{
+	int			status;
+
+	if (conn->sock < 0 ||
+		conn->asyncStatus != PGASYNC_COPY_OUT ||
+		conn->copy_is_binary)
+	{
+		printfPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext("PQgetline: not doing text COPY OUT\n"));
+		*s = '\0';
+		return EOF;
+	}
+
+	while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0)
+	{
+		/* need to load more data */
+		if (pqWait(TRUE, FALSE, conn) ||
+			pqReadData(conn) < 0)
+		{
+			*s = '\0';
+			return EOF;
+		}
+	}
+
+	if (status < 0)
+	{
+		/* End of copy detected; gin up old-style terminator */
+		strcpy(s, "\\.");
+		return 0;
+	}
+
+	/* Add null terminator, and strip trailing \n if present */
+	if (s[status - 1] == '\n')
+	{
+		s[status - 1] = '\0';
+		return 0;
+	}
+	else
+	{
+		s[status] = '\0';
+		return 1;
+	}
+}
+
+/*
+ * PQgetlineAsync - gets a COPY data row without blocking.
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
+{
+	int			msgLength;
+	int			avail;
+
+	if (conn->asyncStatus != PGASYNC_COPY_OUT)
+		return -1;				/* we are not doing a copy... */
+
+	/*
+	 * Recognize the next input message.  To make life simpler for async
+	 * callers, we keep returning 0 until the next message is fully available
+	 * even if it is not Copy Data.  This should keep PQendcopy from blocking.
+	 * (Note: unlike pqGetCopyData3, we do not change asyncStatus here.)
+	 */
+	msgLength = getCopyDataMessage(conn);
+	if (msgLength < 0)
+		return -1;				/* end-of-copy or error */
+	if (msgLength == 0)
+		return 0;				/* no data yet */
+
+	/*
+	 * Move data from libpq's buffer to the caller's.  In the case where a
+	 * prior call found the caller's buffer too small, we use
+	 * conn->copy_already_done to remember how much of the row was already
+	 * returned to the caller.
+	 */
+	conn->inCursor += conn->copy_already_done;
+	avail = msgLength - 4 - conn->copy_already_done;
+	if (avail <= bufsize)
+	{
+		/* Able to consume the whole message */
+		memcpy(buffer, &conn->inBuffer[conn->inCursor], avail);
+		/* Mark message consumed */
+		conn->inStart = conn->inCursor + avail;
+		/* Reset state for next time */
+		conn->copy_already_done = 0;
+		return avail;
+	}
+	else
+	{
+		/* We must return a partial message */
+		memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize);
+		/* The message is NOT consumed from libpq's buffer */
+		conn->copy_already_done += bufsize;
+		return bufsize;
+	}
+}
+
+/*
+ * PQendcopy
+ *
+ * See fe-exec.c for documentation.
+ */
+int
+pqEndcopy3(PGconn *conn)
+{
+	PGresult   *result;
+
+	if (conn->asyncStatus != PGASYNC_COPY_IN &&
+		conn->asyncStatus != PGASYNC_COPY_OUT)
+	{
+		printfPQExpBuffer(&conn->errorMessage,
+						  libpq_gettext("no COPY in progress\n"));
+		return 1;
+	}
+
+	/* Send the CopyDone message if needed */
+	if (conn->asyncStatus == PGASYNC_COPY_IN)
+	{
+		if (pqPutMsgStart('c', false, conn) < 0 ||
+			pqPutMsgEnd(conn) < 0)
+			return 1;
+
+		/*
+		 * If we sent the COPY command in extended-query mode, we must issue a
+		 * Sync as well.
+		 */
+		if (conn->queryclass != PGQUERY_SIMPLE)
+		{
+			if (pqPutMsgStart('S', false, conn) < 0 ||
+				pqPutMsgEnd(conn) < 0)
+				return 1;
+		}
+	}
+
+	/*
+	 * make sure no data is waiting to be sent, abort if we are non-blocking
+	 * and the flush fails
+	 */
+	if (pqFlush(conn) && pqIsnonblocking(conn))
+		return 1;
+
+	/* Return to active duty */
+	conn->asyncStatus = PGASYNC_BUSY;
+	resetPQExpBuffer(&conn->errorMessage);
+
+	/*
+	 * Non blocking connections may have to abort at this point.  If everyone
+	 * played the game there should be no problem, but in error scenarios the
+	 * expected messages may not have arrived yet.	(We are assuming that the
+	 * backend's packetizing will ensure that CommandComplete arrives along
+	 * with the CopyDone; are there corner cases where that doesn't happen?)
+	 */
+	if (pqIsnonblocking(conn) && PQisBusy(conn))
+		return 1;
+
+	/* Wait for the completion response */
+	result = PQgetResult(conn);
+
+	/* Expecting a successful result */
+	if (result && result->resultStatus == PGRES_COMMAND_OK)
+	{
+		PQclear(result);
+		return 0;
+	}
+
+	/*
+	 * Trouble. For backwards-compatibility reasons, we issue the error
+	 * message as if it were a notice (would be nice to get rid of this
+	 * silliness, but too many apps probably don't handle errors from
+	 * PQendcopy reasonably).  Note that the app can still obtain the error
+	 * status from the PGconn object.
+	 */
+	if (conn->errorMessage.len > 0)
+	{
+		/* We have to strip the trailing newline ... pain in neck... */
+		char		svLast = conn->errorMessage.data[conn->errorMessage.len - 1];
+
+		if (svLast == '\n')
+			conn->errorMessage.data[conn->errorMessage.len - 1] = '\0';
+		pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data);
+		conn->errorMessage.data[conn->errorMessage.len - 1] = svLast;
+	}
+
+	PQclear(result);
+
+	return 1;
+}
+
+
+/*
+ * PQfn - Send a function call to the POSTGRES backend.
+ *
+ * See fe-exec.c for documentation.
+ */
+PGresult *
+pqFunctionCall3(PGconn *conn, Oid fnid,
+				int *result_buf, int *actual_result_len,
+				int result_is_int,
+				const PQArgBlock *args, int nargs)
+{
+	bool		needInput = false;
+	ExecStatusType status = PGRES_FATAL_ERROR;
+	char		id;
+	int			msgLength;
+	int			avail;
+	int			i;
+
+	/* PQfn already validated connection state */
+
+	if (pqPutMsgStart('F', false, conn) < 0 ||	/* function call msg */
+		pqPutInt(fnid, 4, conn) < 0 ||	/* function id */
+		pqPutInt(1, 2, conn) < 0 ||		/* # of format codes */
+		pqPutInt(1, 2, conn) < 0 ||		/* format code: BINARY */
+		pqPutInt(nargs, 2, conn) < 0)	/* # of args */
+	{
+		pqHandleSendFailure(conn);
+		return NULL;
+	}
+
+	for (i = 0; i < nargs; ++i)
+	{							/* len.int4 + contents	   */
+		if (pqPutInt(args[i].len, 4, conn))
+		{
+			pqHandleSendFailure(conn);
+			return NULL;
+		}
+		if (args[i].len == -1)
+			continue;			/* it's NULL */
+
+		if (args[i].isint)
+		{
+			if (pqPutInt(args[i].u.integer, args[i].len, conn))
+			{
+				pqHandleSendFailure(conn);
+				return NULL;
+			}
+		}
+		else
+		{
+			if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
+			{
+				pqHandleSendFailure(conn);
+				return NULL;
+			}
+		}
+	}
+
+	if (pqPutInt(1, 2, conn) < 0)		/* result format code: BINARY */
+	{
+		pqHandleSendFailure(conn);
+		return NULL;
+	}
+
+	if (pqPutMsgEnd(conn) < 0 ||
+		pqFlush(conn))
+	{
+		pqHandleSendFailure(conn);
+		return NULL;
+	}
+
+	for (;;)
+	{
+		if (needInput)
+		{
+			/* Wait for some data to arrive (or for the channel to close) */
+			if (pqWait(TRUE, FALSE, conn) ||
+				pqReadData(conn) < 0)
+				break;
+		}
+
+		/*
+		 * Scan the message. If we run out of data, loop around to try again.
+		 */
+		needInput = true;
+
+		conn->inCursor = conn->inStart;
+		if (pqGetc(&id, conn))
+			continue;
+		if (pqGetInt(&msgLength, 4, conn))
+			continue;
+
+		/*
+		 * Try to validate message type/length here.  A length less than 4 is
+		 * definitely broken.  Large lengths should only be believed for a few
+		 * message types.
+		 */
+		if (msgLength < 4)
+		{
+			handleSyncLoss(conn, id, msgLength);
+			break;
+		}
+		if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
+		{
+			handleSyncLoss(conn, id, msgLength);
+			break;
+		}
+
+		/*
+		 * Can't process if message body isn't all here yet.
+		 */
+		msgLength -= 4;
+		avail = conn->inEnd - conn->inCursor;
+		if (avail < msgLength)
+		{
+			/*
+			 * Before looping, enlarge the input buffer if needed to hold the
+			 * whole message.  See notes in parseInput.
+			 */
+			if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
+									 conn))
+			{
+				/*
+				 * XXX add some better recovery code... plan is to skip over
+				 * the message using its length, then report an error. For the
+				 * moment, just treat this like loss of sync (which indeed it
+				 * might be!)
+				 */
+				handleSyncLoss(conn, id, msgLength);
+				break;
+			}
+			continue;
+		}
+
+		/*
+		 * We should see V or E response to the command, but might get N
+		 * and/or A notices first. We also need to swallow the final Z before
+		 * returning.
+		 */
+		switch (id)
+		{
+			case 'V':			/* function result */
+				if (pqGetInt(actual_result_len, 4, conn))
+					continue;
+				if (*actual_result_len != -1)
+				{
+					if (result_is_int)
+					{
+						if (pqGetInt(result_buf, *actual_result_len, conn))
+							continue;
+					}
+					else
+					{
+						if (pqGetnchar((char *) result_buf,
+									   *actual_result_len,
+									   conn))
+							continue;
+					}
+				}
+				/* correctly finished function result message */
+				status = PGRES_COMMAND_OK;
+				break;
+			case 'E':			/* error return */
+				if (pqGetErrorNotice3(conn, true))
+					continue;
+				status = PGRES_FATAL_ERROR;
+				break;
+			case 'A':			/* notify message */
+				/* handle notify and go back to processing return values */
+				if (getNotify(conn))
+					continue;
+				break;
+			case 'N':			/* notice */
+				/* handle notice and go back to processing return values */
+				if (pqGetErrorNotice3(conn, false))
+					continue;
+				break;
+			case 'Z':			/* backend is ready for new query */
+				if (getReadyForQuery(conn))
+					continue;
+				/* consume the message and exit */
+				conn->inStart += 5 + msgLength;
+				/* if we saved a result object (probably an error), use it */
+				if (conn->result)
+					return pqPrepareAsyncResult(conn);
+				return PQmakeEmptyPGresult(conn, status);
+			case 'S':			/* parameter status */
+				if (getParameterStatus(conn))
+					continue;
+				break;
+			default:
+				/* The backend violates the protocol. */
+				printfPQExpBuffer(&conn->errorMessage,
+								  libpq_gettext("protocol error: id=0x%x\n"),
+								  id);
+				pqSaveErrorResult(conn);
+				/* trust the specified message length as what to skip */
+				conn->inStart += 5 + msgLength;
+				return pqPrepareAsyncResult(conn);
+		}
+		/* Completed this message, keep going */
+		/* trust the specified message length as what to skip */
+		conn->inStart += 5 + msgLength;
+		needInput = false;
+	}
+
+	/*
+	 * We fall out of the loop only upon failing to read data.
+	 * conn->errorMessage has been set by pqWait or pqReadData. We want to
+	 * append it to any already-received error message.
+	 */
+	pqSaveErrorResult(conn);
+	return pqPrepareAsyncResult(conn);
+}
+
+
+/*
+ * Construct startup packet
+ *
+ * Returns a malloc'd packet buffer, or NULL if out of memory
+ */
+char *
+pqBuildStartupPacket3(PGconn *conn, int *packetlen,
+					  const PQEnvironmentOption *options)
+{
+	char	   *startpacket;
+
+	*packetlen = build_startup_packet(conn, NULL, options);
+	startpacket = (char *) malloc(*packetlen);
+	if (!startpacket)
+		return NULL;
+	*packetlen = build_startup_packet(conn, startpacket, options);
+	return startpacket;
+}
+
+/*
+ * Build a startup packet given a filled-in PGconn structure.
+ *
+ * We need to figure out how much space is needed, then fill it in.
+ * To avoid duplicate logic, this routine is called twice: the first time
+ * (with packet == NULL) just counts the space needed, the second time
+ * (with packet == allocated space) fills it in.  Return value is the number
+ * of bytes used.
+ */
+static int
+build_startup_packet(const PGconn *conn, char *packet,
+					 const PQEnvironmentOption *options)
+{
+	int			packet_len = 0;
+	const PQEnvironmentOption *next_eo;
+	const char *val;
+
+	/* Protocol version comes first. */
+	if (packet)
+	{
+		ProtocolVersion pv = htonl(conn->pversion);
+
+		memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion));
+	}
+	packet_len += sizeof(ProtocolVersion);
+
+	/* Add user name, database name, options */
+
+#define ADD_STARTUP_OPTION(optname, optval) \
+	do { \
+		if (packet) \
+			strcpy(packet + packet_len, optname); \
+		packet_len += strlen(optname) + 1; \
+		if (packet) \
+			strcpy(packet + packet_len, optval); \
+		packet_len += strlen(optval) + 1; \
+	} while(0)
+
+	if (conn->pguser && conn->pguser[0])
+		ADD_STARTUP_OPTION("user", conn->pguser);
+	if (conn->dbName && conn->dbName[0])
+		ADD_STARTUP_OPTION("database", conn->dbName);
+	if (conn->replication && conn->replication[0])
+		ADD_STARTUP_OPTION("replication", conn->replication);
+	if (conn->pgoptions && conn->pgoptions[0])
+		ADD_STARTUP_OPTION("options", conn->pgoptions);
+	if (conn->send_appname)
+	{
+		/* Use appname if present, otherwise use fallback */
+		val = conn->appname ? conn->appname : conn->fbappname;
+		if (val && val[0])
+			ADD_STARTUP_OPTION("application_name", val);
+	}
+
+	if (conn->client_encoding_initial && conn->client_encoding_initial[0])
+		ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial);
+
+	/* Add any environment-driven GUC settings needed */
+	for (next_eo = options; next_eo->envName; next_eo++)
+	{
+		if ((val = getenv(next_eo->envName)) != NULL)
+		{
+			if (pg_strcasecmp(val, "default") != 0)
+				ADD_STARTUP_OPTION(next_eo->pgName, val);
+		}
+	}
+
+	/* Add trailing terminator */
+	if (packet)
+		packet[packet_len] = '\0';
+	packet_len++;
+
+	return packet_len;
+}
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index 1af8df6..23cf729 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -160,3 +160,6 @@ PQconnectStartParams      157
 PQping                    158
 PQpingParams              159
 PQlibVersion              160
+PQsetRowProcessor	  161
+PQsetRowProcessorErrMsg	  162
+PQskipRemainingResults	  163
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 27a9805..4605e49 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -2693,6 +2693,9 @@ makeEmptyPGconn(void)
 	conn->wait_ssl_try = false;
 #endif
 
+	/* set default row processor */
+	PQsetRowProcessor(conn, NULL, NULL);
+
 	/*
 	 * We try to send at least 8K at a time, which is the usual size of pipe
 	 * buffers on Unix systems.  That way, when we are sending a large amount
@@ -2711,8 +2714,13 @@ makeEmptyPGconn(void)
 	initPQExpBuffer(&conn->errorMessage);
 	initPQExpBuffer(&conn->workBuffer);
 
+	/* set up initial row buffer */
+	conn->rowBufLen = 32;
+	conn->rowBuf = (PGrowValue *)malloc(conn->rowBufLen * sizeof(PGrowValue));
+
 	if (conn->inBuffer == NULL ||
 		conn->outBuffer == NULL ||
+		conn->rowBuf == NULL ||
 		PQExpBufferBroken(&conn->errorMessage) ||
 		PQExpBufferBroken(&conn->workBuffer))
 	{
@@ -2814,6 +2822,8 @@ freePGconn(PGconn *conn)
 		free(conn->inBuffer);
 	if (conn->outBuffer)
 		free(conn->outBuffer);
+	if (conn->rowBuf)
+		free(conn->rowBuf);
 	termPQExpBuffer(&conn->errorMessage);
 	termPQExpBuffer(&conn->workBuffer);
 
@@ -5078,3 +5088,4 @@ PQregisterThreadLock(pgthreadlock_t newhandler)
 
 	return prev;
 }
+
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index b743566..d7f3ae9 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -66,6 +66,7 @@ static PGresult *PQexecFinish(PGconn *conn);
 static int PQsendDescribe(PGconn *conn, char desc_type,
 			   const char *desc_target);
 static int	check_field_number(const PGresult *res, int field_num);
+static int	pqAddRow(PGresult *res, void *param, PGrowValue *columns);
 
 
 /* ----------------
@@ -160,6 +161,7 @@ PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status)
 	result->curBlock = NULL;
 	result->curOffset = 0;
 	result->spaceLeft = 0;
+	result->rowProcessorErrMsg = NULL;
 
 	if (conn)
 	{
@@ -701,7 +703,6 @@ pqClearAsyncResult(PGconn *conn)
 	if (conn->result)
 		PQclear(conn->result);
 	conn->result = NULL;
-	conn->curTuple = NULL;
 }
 
 /*
@@ -756,7 +757,6 @@ pqPrepareAsyncResult(PGconn *conn)
 	 */
 	res = conn->result;
 	conn->result = NULL;		/* handing over ownership to caller */
-	conn->curTuple = NULL;		/* just in case */
 	if (!res)
 		res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
 	else
@@ -828,6 +828,73 @@ pqInternalNotice(const PGNoticeHooks *hooks, const char *fmt,...)
 }
 
 /*
+ * PQsetRowProcessor
+ *   Set function that copies column data out from network buffer.
+ */
+void
+PQsetRowProcessor(PGconn *conn, PQrowProcessor func, void *param)
+{
+	conn->rowProcessor = (func ? func : pqAddRow);
+	conn->rowProcessorParam = param;
+}
+
+/*
+ * PQsetRowProcessorErrMsg
+ *    Set the error message pass back to the caller of RowProcessor.
+ *
+ *    You can replace the previous message by alternative mes, or clear
+ *    it with NULL.
+ */
+void
+PQsetRowProcessorErrMsg(PGresult *res, char *msg)
+{
+	if (msg)
+		res->rowProcessorErrMsg = pqResultStrdup(res, msg);
+	else
+		res->rowProcessorErrMsg = NULL;
+}
+
+/*
+ * pqAddRow
+ *	  add a row to the PGresult structure, growing it if necessary
+ *	  Returns TRUE if OK, FALSE if not enough memory to add the row.
+ */
+static int
+pqAddRow(PGresult *res, void *param, PGrowValue *columns)
+{
+	PGresAttValue *tup;
+	int			nfields = res->numAttributes;
+	int			i;
+
+	tup = (PGresAttValue *)
+		pqResultAlloc(res, nfields * sizeof(PGresAttValue), TRUE);
+	if (tup == NULL)
+		return FALSE;
+
+	for (i = 0 ; i < nfields ; i++)
+	{
+		tup[i].len = columns[i].len;
+		if (tup[i].len == NULL_LEN)
+		{
+			tup[i].value = res->null_field;
+		}
+		else
+		{
+			bool isbinary = (res->attDescs[i].format != 0);
+			tup[i].value = (char *)pqResultAlloc(res, tup[i].len + 1, isbinary);
+			if (tup[i].value == NULL)
+				return FALSE;
+
+			memcpy(tup[i].value, columns[i].value, tup[i].len);
+			/* We have to terminate this ourselves */
+			tup[i].value[tup[i].len] = '\0';
+		}
+	}
+
+	return pqAddTuple(res, tup);
+}
+
+/*
  * pqAddTuple
  *	  add a row pointer to the PGresult structure, growing it if necessary
  *	  Returns TRUE if OK, FALSE if not enough memory to add the row
@@ -1223,7 +1290,6 @@ PQsendQueryStart(PGconn *conn)
 
 	/* initialize async result-accumulation state */
 	conn->result = NULL;
-	conn->curTuple = NULL;
 
 	/* ready to send command message */
 	return true;
@@ -1832,6 +1898,22 @@ PQexecFinish(PGconn *conn)
 }
 
 /*
+ * Exaust remaining Data Rows in curret conn.
+ */
+PGresult *
+PQskipRemainingResults(PGconn *conn)
+{
+	pqClearAsyncResult(conn);
+
+	/* conn->result is set NULL in pqClearAsyncResult() */
+	pqSaveErrorResult(conn);
+
+	/* Skip over remaining Data Row messages */
+	PQgetResult(conn);
+}
+
+
+/*
  * PQdescribePrepared
  *	  Obtain information about a previously prepared statement
  *
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index ce0eac3..d11cb3c 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -219,6 +219,25 @@ pqGetnchar(char *s, size_t len, PGconn *conn)
 }
 
 /*
+ * pqGetnchar:
+ *	skip len bytes in input buffer.
+ */
+int
+pqSkipnchar(size_t len, PGconn *conn)
+{
+	if (len > (size_t) (conn->inEnd - conn->inCursor))
+		return EOF;
+
+	conn->inCursor += len;
+
+	if (conn->Pfdebug)
+		fprintf(conn->Pfdebug, "From backend (%lu skipped)\n",
+				(unsigned long) len);
+
+	return 0;
+}
+
+/*
  * pqPutnchar:
  *	write exactly len bytes to the current message
  */
diff --git a/src/interfaces/libpq/fe-protocol2.c b/src/interfaces/libpq/fe-protocol2.c
index a7c3899..ae4d7b0 100644
--- a/src/interfaces/libpq/fe-protocol2.c
+++ b/src/interfaces/libpq/fe-protocol2.c
@@ -569,6 +569,8 @@ pqParseInput2(PGconn *conn)
 						/* Read another tuple of a normal query response */
 						if (getAnotherTuple(conn, FALSE))
 							return;
+						/* getAnotherTuple moves inStart itself */
+						continue;
 					}
 					else
 					{
@@ -585,6 +587,8 @@ pqParseInput2(PGconn *conn)
 						/* Read another tuple of a normal query response */
 						if (getAnotherTuple(conn, TRUE))
 							return;
+						/* getAnotherTuple moves inStart itself */
+						continue;
 					}
 					else
 					{
@@ -703,52 +707,51 @@ failure:
 
 /*
  * parseInput subroutine to read a 'B' or 'D' (row data) message.
- * We add another tuple to the existing PGresult structure.
+ * It fills rowbuf with column pointers and then calls row processor.
  * Returns: 0 if completed message, EOF if error or not enough data yet.
  *
  * Note that if we run out of data, we have to suspend and reprocess
- * the message after more data is received.  We keep a partially constructed
- * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ * the message after more data is received.
  */
 static int
 getAnotherTuple(PGconn *conn, bool binary)
 {
 	PGresult   *result = conn->result;
 	int			nfields = result->numAttributes;
-	PGresAttValue *tup;
+	PGrowValue  *rowbuf;
 
 	/* the backend sends us a bitmap of which attributes are null */
 	char		std_bitmap[64]; /* used unless it doesn't fit */
 	char	   *bitmap = std_bitmap;
 	int			i;
+	int			rp;
 	size_t		nbytes;			/* the number of bytes in bitmap  */
 	char		bmap;			/* One byte of the bitmap */
 	int			bitmap_index;	/* Its index */
 	int			bitcnt;			/* number of bits examined in current byte */
 	int			vlen;			/* length of the current field value */
 
+	/* resize row buffer if needed */
+	if (nfields > conn->rowBufLen)
+	{
+		rowbuf = realloc(conn->rowBuf, nfields * sizeof(PGrowValue));
+		if (!rowbuf)
+			goto rowProcessError;
+		conn->rowBuf = rowbuf;
+		conn->rowBufLen = nfields;
+	}
+	else
+	{
+		rowbuf = conn->rowBuf;
+	}
+
 	result->binary = binary;
 
-	/* Allocate tuple space if first time for this data message */
-	if (conn->curTuple == NULL)
+	if (binary)
 	{
-		conn->curTuple = (PGresAttValue *)
-			pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
-		if (conn->curTuple == NULL)
-			goto outOfMemory;
-		MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
-
-		/*
-		 * If it's binary, fix the column format indicators.  We assume the
-		 * backend will consistently send either B or D, not a mix.
-		 */
-		if (binary)
-		{
-			for (i = 0; i < nfields; i++)
-				result->attDescs[i].format = 1;
-		}
+		for (i = 0; i < nfields; i++)
+			result->attDescs[i].format = 1;
 	}
-	tup = conn->curTuple;
 
 	/* Get the null-value bitmap */
 	nbytes = (nfields + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
@@ -757,7 +760,7 @@ getAnotherTuple(PGconn *conn, bool binary)
 	{
 		bitmap = (char *) malloc(nbytes);
 		if (!bitmap)
-			goto outOfMemory;
+			goto rowProcessError;
 	}
 
 	if (pqGetnchar(bitmap, nbytes, conn))
@@ -771,34 +774,29 @@ getAnotherTuple(PGconn *conn, bool binary)
 	for (i = 0; i < nfields; i++)
 	{
 		if (!(bmap & 0200))
-		{
-			/* if the field value is absent, make it a null string */
-			tup[i].value = result->null_field;
-			tup[i].len = NULL_LEN;
-		}
+			vlen = NULL_LEN;
+		else if (pqGetInt(&vlen, 4, conn))
+				goto EOFexit;
 		else
 		{
-			/* get the value length (the first four bytes are for length) */
-			if (pqGetInt(&vlen, 4, conn))
-				goto EOFexit;
 			if (!binary)
 				vlen = vlen - 4;
 			if (vlen < 0)
 				vlen = 0;
-			if (tup[i].value == NULL)
-			{
-				tup[i].value = (char *) pqResultAlloc(result, vlen + 1, binary);
-				if (tup[i].value == NULL)
-					goto outOfMemory;
-			}
-			tup[i].len = vlen;
-			/* read in the value */
-			if (vlen > 0)
-				if (pqGetnchar((char *) (tup[i].value), vlen, conn))
-					goto EOFexit;
-			/* we have to terminate this ourselves */
-			tup[i].value[vlen] = '\0';
 		}
+
+		/*
+		 * rowbuf[i].value always points to the next address of the
+		 * length field even if the value is NULL, to allow safe
+		 * size estimates and data copy.
+		 */
+		rowbuf[i].value = conn->inBuffer + conn->inCursor;
+		rowbuf[i].len = vlen;
+
+		/* Skip the value */
+		if (vlen > 0 && pqSkipnchar(vlen, conn))
+			goto EOFexit;
+
 		/* advance the bitmap stuff */
 		bitcnt++;
 		if (bitcnt == BITS_PER_BYTE)
@@ -811,33 +809,56 @@ getAnotherTuple(PGconn *conn, bool binary)
 			bmap <<= 1;
 	}
 
-	/* Success!  Store the completed tuple in the result */
-	if (!pqAddTuple(result, tup))
-		goto outOfMemory;
-	/* and reset for a new message */
-	conn->curTuple = NULL;
-
 	if (bitmap != std_bitmap)
 		free(bitmap);
-	return 0;
+	bitmap = NULL;
+
+	/* tag the row as parsed */
+	conn->inStart = conn->inCursor;
+
+	/* Pass the completed row values to rowProcessor */
+	rp= conn->rowProcessor(result, conn->rowProcessorParam, rowbuf);
+	if (rp == 1)
+		return 0;
+	else if (rp == 2 && pqIsnonblocking(conn))
+		/* processor requested early exit */
+		return EOF;
+	else if (rp != 0)
+		PQsetRowProcessorErrMsg(result, libpq_gettext("invalid return value from row processor\n"));
+
+rowProcessError:
 
-outOfMemory:
 	/* Replace partially constructed result with an error result */
 
-	/*
-	 * we do NOT use pqSaveErrorResult() here, because of the likelihood that
-	 * there's not enough memory to concatenate messages...
-	 */
-	pqClearAsyncResult(conn);
-	printfPQExpBuffer(&conn->errorMessage,
-					  libpq_gettext("out of memory for query result\n"));
+	if (result->rowProcessorErrMsg)
+	{
+		printfPQExpBuffer(&conn->errorMessage, "%s", result->rowProcessorErrMsg);
+		pqSaveErrorResult(conn);
+	}
+	else
+	{
+		/*
+		 * we do NOT use pqSaveErrorResult() here, because of the likelihood that
+		 * there's not enough memory to concatenate messages...
+		 */
+		pqClearAsyncResult(conn);
+		resetPQExpBuffer(&conn->errorMessage);
 
-	/*
-	 * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
-	 * do to recover...
-	 */
-	conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
+		/*
+		 * If error message is passed from RowProcessor, set it into
+		 * PGconn, assume out of memory if not.
+		 */
+		appendPQExpBufferStr(&conn->errorMessage,
+							 libpq_gettext("out of memory for query result\n"));
+
+		/*
+		 * XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
+		 * do to recover...
+		 */
+		conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
+	}
 	conn->asyncStatus = PGASYNC_READY;
+
 	/* Discard the failed message --- good idea? */
 	conn->inStart = conn->inEnd;
 
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 892dcbc..0260ba6 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -327,6 +327,9 @@ pqParseInput3(PGconn *conn)
 						/* Read another tuple of a normal query response */
 						if (getAnotherTuple(conn, msgLength))
 							return;
+
+						/* getAnotherTuple() moves inStart itself */
+						continue;
 					}
 					else if (conn->result != NULL &&
 							 conn->result->resultStatus == PGRES_FATAL_ERROR)
@@ -613,33 +616,22 @@ failure:
 
 /*
  * parseInput subroutine to read a 'D' (row data) message.
- * We add another tuple to the existing PGresult structure.
+ * It fills rowbuf with column pointers and then calls row processor.
  * Returns: 0 if completed message, EOF if error or not enough data yet.
  *
  * Note that if we run out of data, we have to suspend and reprocess
- * the message after more data is received.  We keep a partially constructed
- * tuple in conn->curTuple, and avoid reallocating already-allocated storage.
+ * the message after more data is received.
  */
 static int
 getAnotherTuple(PGconn *conn, int msgLength)
 {
 	PGresult   *result = conn->result;
 	int			nfields = result->numAttributes;
-	PGresAttValue *tup;
+	PGrowValue  *rowbuf;
 	int			tupnfields;		/* # fields from tuple */
 	int			vlen;			/* length of the current field value */
 	int			i;
-
-	/* Allocate tuple space if first time for this data message */
-	if (conn->curTuple == NULL)
-	{
-		conn->curTuple = (PGresAttValue *)
-			pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
-		if (conn->curTuple == NULL)
-			goto outOfMemory;
-		MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
-	}
-	tup = conn->curTuple;
+	int			rp;
 
 	/* Get the field count and make sure it's what we expect */
 	if (pqGetInt(&tupnfields, 2, conn))
@@ -652,52 +644,88 @@ getAnotherTuple(PGconn *conn, int msgLength)
 				 libpq_gettext("unexpected field count in \"D\" message\n"));
 		pqSaveErrorResult(conn);
 		/* Discard the failed message by pretending we read it */
-		conn->inCursor = conn->inStart + 5 + msgLength;
+		conn->inStart += 5 + msgLength;
 		return 0;
 	}
 
+	/* resize row buffer if needed */
+	rowbuf = conn->rowBuf;
+	if (nfields > conn->rowBufLen)
+	{
+		rowbuf = realloc(conn->rowBuf, nfields * sizeof(PGrowValue));
+		if (!rowbuf)
+		{
+			goto outOfMemory1;
+		}
+		conn->rowBuf = rowbuf;
+		conn->rowBufLen = nfields;
+	}
+
 	/* Scan the fields */
 	for (i = 0; i < nfields; i++)
 	{
 		/* get the value length */
 		if (pqGetInt(&vlen, 4, conn))
-			return EOF;
+			goto protocolError;
 		if (vlen == -1)
-		{
-			/* null field */
-			tup[i].value = result->null_field;
-			tup[i].len = NULL_LEN;
-			continue;
-		}
-		if (vlen < 0)
+			vlen = NULL_LEN;
+		else if (vlen < 0)
 			vlen = 0;
-		if (tup[i].value == NULL)
-		{
-			bool		isbinary = (result->attDescs[i].format != 0);
 
-			tup[i].value = (char *) pqResultAlloc(result, vlen + 1, isbinary);
-			if (tup[i].value == NULL)
-				goto outOfMemory;
-		}
-		tup[i].len = vlen;
-		/* read in the value */
-		if (vlen > 0)
-			if (pqGetnchar((char *) (tup[i].value), vlen, conn))
-				return EOF;
-		/* we have to terminate this ourselves */
-		tup[i].value[vlen] = '\0';
+		/*
+		 * rowbuf[i].value always points to the next address of the
+		 * length field even if the value is NULL, to allow safe
+		 * size estimates and data copy.
+		 */
+		rowbuf[i].value = conn->inBuffer + conn->inCursor;
+		rowbuf[i].len = vlen;
+
+		/* Skip to the next length field */
+		if (vlen > 0 && pqSkipnchar(vlen, conn))
+			goto protocolError;
 	}
 
-	/* Success!  Store the completed tuple in the result */
-	if (!pqAddTuple(result, tup))
-		goto outOfMemory;
-	/* and reset for a new message */
-	conn->curTuple = NULL;
+	/* tag the row as parsed, check if correctly */
+	conn->inStart += 5 + msgLength;
+	if (conn->inCursor != conn->inStart)
+		goto protocolError;
 
+	/* Pass the completed row values to rowProcessor */
+	rp = conn->rowProcessor(result, conn->rowProcessorParam, rowbuf);
+	if (rp == 1)
+	{
+		/* everything is good */
+		return 0;
+	}
+	if (rp == 2 && pqIsnonblocking(conn))
+	{
+		/* processor requested early exit */
+		return EOF;
+	}
+
+	/* there was some problem */
+	if (rp == 0)
+	{
+		if (result->rowProcessorErrMsg == NULL)
+			goto outOfMemory2;
+
+		/* use supplied error message */
+		printfPQExpBuffer(&conn->errorMessage, "%s", result->rowProcessorErrMsg);
+	}
+	else
+	{
+		/* row processor messed up */
+		printfPQExpBuffer(&conn->errorMessage,
+						  libpq_gettext("invalid return value from row processor\n"));
+	}
+	pqSaveErrorResult(conn);
 	return 0;
 
-outOfMemory:
+outOfMemory1:
+	/* Discard the failed message by pretending we read it */
+	conn->inStart += 5 + msgLength;
 
+outOfMemory2:
 	/*
 	 * Replace partially constructed result with an error result. First
 	 * discard the old result to try to win back some memory.
@@ -706,9 +734,14 @@ outOfMemory:
 	printfPQExpBuffer(&conn->errorMessage,
 					  libpq_gettext("out of memory for query result\n"));
 	pqSaveErrorResult(conn);
+	return 0;
 
+protocolError:
+	printfPQExpBuffer(&conn->errorMessage,
+					  libpq_gettext("invalid row contents\n"));
+	pqSaveErrorResult(conn);
 	/* Discard the failed message by pretending we read it */
-	conn->inCursor = conn->inStart + 5 + msgLength;
+	conn->inStart += 5 + msgLength;
 	return 0;
 }
 
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index ef26ab9..2d913c4 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -149,6 +149,17 @@ typedef struct pgNotify
 	struct pgNotify *next;		/* list link */
 } PGnotify;
 
+/* PGrowValue points a column value of in network buffer.
+ * Value is a string without null termination and length len.
+ * NULL is represented as len < 0, value points then to place
+ * where value would have been.
+ */
+typedef struct pgRowValue
+{
+	int			len;			/* length in bytes of the value */
+	char	   *value;			/* actual value, without null termination */
+} PGrowValue;
+
 /* Function types for notice-handling callbacks */
 typedef void (*PQnoticeReceiver) (void *arg, const PGresult *res);
 typedef void (*PQnoticeProcessor) (void *arg, const char *message);
@@ -367,6 +378,8 @@ extern PGresult *PQexecPrepared(PGconn *conn,
 			   const int *paramFormats,
 			   int resultFormat);
 
+extern PGresult *PQskipRemainingResults(PGconn *conn);
+
 /* Interface for multiple-result or asynchronous queries */
 extern int	PQsendQuery(PGconn *conn, const char *query);
 extern int PQsendQueryParams(PGconn *conn,
@@ -416,6 +429,37 @@ extern PGPing PQping(const char *conninfo);
 extern PGPing PQpingParams(const char *const * keywords,
 			 const char *const * values, int expand_dbname);
 
+/*
+ * Typedef for alternative row processor.
+ *
+ * Columns array will contain PQnfields() entries, each one
+ * pointing to particular column data in network buffer.
+ * This function is supposed to copy data out from there
+ * and store somewhere.  NULL is signified with len<0.
+ *
+ * This function must return 1 for success and must return 0 for
+ * failure and may set error message by PQsetRowProcessorErrMsg.  It
+ * is assumed by caller as out of memory when the error message is not
+ * set on failure. This function is assumed not to throw any
+ * exception.
+ */
+typedef int (*PQrowProcessor)(PGresult *res, void *param,
+								PGrowValue *columns);
+
+/*
+ * Set alternative row data processor for PGconn.
+ *
+ * By registering this function, pg_result disables its own result
+ * store and calls it for rows one by one.
+ *
+ * func is row processor function. See the typedef RowProcessor.
+ *
+ * rowProcessorParam is the contextual variable that passed to
+ * RowProcessor.
+ */
+extern void PQsetRowProcessor(PGconn *conn, PQrowProcessor func,
+								   void *rowProcessorParam);
+
 /* Force the write buffer to be written (or at least try) */
 extern int	PQflush(PGconn *conn);
 
@@ -454,6 +498,7 @@ extern char *PQcmdTuples(PGresult *res);
 extern char *PQgetvalue(const PGresult *res, int tup_num, int field_num);
 extern int	PQgetlength(const PGresult *res, int tup_num, int field_num);
 extern int	PQgetisnull(const PGresult *res, int tup_num, int field_num);
+extern void	PQsetRowProcessorErrMsg(PGresult *res, char *msg);
 extern int	PQnparams(const PGresult *res);
 extern Oid	PQparamtype(const PGresult *res, int param_num);
 
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 987311e..1fc5aab 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -209,6 +209,9 @@ struct pg_result
 	PGresult_data *curBlock;	/* most recently allocated block */
 	int			curOffset;		/* start offset of free space in block */
 	int			spaceLeft;		/* number of free bytes remaining in block */
+
+	/* temp etorage for message from row processor callback */
+	char	   *rowProcessorErrMsg;
 };
 
 /* PGAsyncStatusType defines the state of the query-execution state machine */
@@ -398,7 +401,6 @@ struct pg_conn
 
 	/* Status for asynchronous result construction */
 	PGresult   *result;			/* result being constructed */
-	PGresAttValue *curTuple;	/* tuple currently being read */
 
 #ifdef USE_SSL
 	bool		allow_ssl_try;	/* Allowed to try SSL negotiation */
@@ -443,6 +445,14 @@ struct pg_conn
 
 	/* Buffer for receiving various parts of messages */
 	PQExpBufferData workBuffer; /* expansible string */
+
+	/*
+	 * Read column data from network buffer.
+	 */
+	PQrowProcessor rowProcessor;/* Function pointer */
+	void *rowProcessorParam;	/* Contextual parameter for rowProcessor */
+	PGrowValue *rowBuf;			/* Buffer for passing values to rowProcessor */
+	int rowBufLen;				/* Number of columns allocated in rowBuf */
 };
 
 /* PGcancel stores all data necessary to cancel a connection. A copy of this
@@ -560,6 +570,7 @@ extern int	pqGets(PQExpBuffer buf, PGconn *conn);
 extern int	pqGets_append(PQExpBuffer buf, PGconn *conn);
 extern int	pqPuts(const char *s, PGconn *conn);
 extern int	pqGetnchar(char *s, size_t len, PGconn *conn);
+extern int	pqSkipnchar(size_t len, PGconn *conn);
 extern int	pqPutnchar(const char *s, size_t len, PGconn *conn);
 extern int	pqGetInt(int *result, size_t bytes, PGconn *conn);
 extern int	pqPutInt(int value, size_t bytes, PGconn *conn);