diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 8345faface..f1d0820510 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -292,8 +292,6 @@ pqParseInput3(PGconn *conn)
 						/* First 'T' in a query sequence */
 						if (getRowDescriptions(conn, msgLength))
 							return;
-						/* getRowDescriptions() moves inStart itself */
-						continue;
 					}
 					else
 					{
@@ -339,8 +337,7 @@ pqParseInput3(PGconn *conn)
 				case 't':		/* Parameter Description */
 					if (getParamDescriptions(conn, msgLength))
 						return;
-					/* getParamDescriptions() moves inStart itself */
-					continue;
+					break;
 				case 'D':		/* Data Row */
 					if (conn->result != NULL &&
 						conn->result->resultStatus == PGRES_TUPLES_OK)
@@ -348,8 +345,6 @@ 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)
@@ -466,7 +461,6 @@ handleSyncLoss(PGconn *conn, char id, int msgLength)
  * command for a prepared statement) containing the attribute data.
  * Returns: 0 if processed message successfully, EOF to suspend parsing
  * (the latter case is not actually used currently).
- * In the former case, conn->inStart has been advanced past the message.
  */
 static int
 getRowDescriptions(PGconn *conn, int msgLength)
@@ -571,19 +565,9 @@ getRowDescriptions(PGconn *conn, int msgLength)
 			result->binary = 0;
 	}
 
-	/* Sanity check that we absorbed all the data */
-	if (conn->inCursor != conn->inStart + 5 + msgLength)
-	{
-		errmsg = libpq_gettext("extraneous data in \"T\" message");
-		goto advance_and_error;
-	}
-
 	/* Success! */
 	conn->result = result;
 
-	/* Advance inStart to show that the "T" message has been processed. */
-	conn->inStart = conn->inCursor;
-
 	/*
 	 * If we're doing a Describe, we're done, and ready to pass the result
 	 * back to the client.
@@ -607,9 +591,6 @@ advance_and_error:
 	if (result && result != conn->result)
 		PQclear(result);
 
-	/* Discard the failed message by pretending we read it */
-	conn->inStart += 5 + msgLength;
-
 	/*
 	 * Replace partially constructed result with an error result. First
 	 * discard the old result to try to win back some memory.
@@ -628,6 +609,12 @@ advance_and_error:
 	printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
 	pqSaveErrorResult(conn);
 
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
 	/*
 	 * Return zero to allow input parsing to continue.  Subsequent "D"
 	 * messages will be ignored until we get to end of data, since an error
@@ -639,12 +626,8 @@ advance_and_error:
 /*
  * 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.
- * In the former case, conn->inStart has been advanced past the message.
- *
- * 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.
+ * Returns: 0 if processed message successfully, EOF to suspend parsing
+ * (the latter case is not actually used currently).
  */
 static int
 getParamDescriptions(PGconn *conn, int msgLength)
@@ -684,33 +667,19 @@ getParamDescriptions(PGconn *conn, int msgLength)
 		result->paramDescs[i].typid = typid;
 	}
 
-	/* Sanity check that we absorbed all the data */
-	if (conn->inCursor != conn->inStart + 5 + msgLength)
-	{
-		errmsg = libpq_gettext("extraneous data in \"t\" message");
-		goto advance_and_error;
-	}
-
 	/* Success! */
 	conn->result = result;
 
-	/* Advance inStart to show that the "t" message has been processed. */
-	conn->inStart = conn->inCursor;
-
 	return 0;
 
 not_enough_data:
-	PQclear(result);
-	return EOF;
+	errmsg = libpq_gettext("insufficient data in \"t\" message");
 
 advance_and_error:
 	/* Discard unsaved result, if any */
 	if (result && result != conn->result)
 		PQclear(result);
 
-	/* Discard the failed message by pretending we read it */
-	conn->inStart += 5 + msgLength;
-
 	/*
 	 * Replace partially constructed result with an error result. First
 	 * discard the old result to try to win back some memory.
@@ -728,6 +697,12 @@ advance_and_error:
 	printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
 	pqSaveErrorResult(conn);
 
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
 	/*
 	 * Return zero to allow input parsing to continue.  Essentially, we've
 	 * replaced the COMMAND_OK result with an error result, but since this
@@ -741,7 +716,6 @@ advance_and_error:
  * We fill rowbuf with column pointers and then call the row processor.
  * Returns: 0 if processed message successfully, EOF to suspend parsing
  * (the latter case is not actually used currently).
- * In the former case, conn->inStart has been advanced past the message.
  */
 static int
 getAnotherTuple(PGconn *conn, int msgLength)
@@ -814,28 +788,14 @@ getAnotherTuple(PGconn *conn, int msgLength)
 		}
 	}
 
-	/* Sanity check that we absorbed all the data */
-	if (conn->inCursor != conn->inStart + 5 + msgLength)
-	{
-		errmsg = libpq_gettext("extraneous data in \"D\" message");
-		goto advance_and_error;
-	}
-
-	/* Advance inStart to show that the "D" message has been processed. */
-	conn->inStart = conn->inCursor;
-
 	/* Process the collected row */
 	errmsg = NULL;
 	if (pqRowProcessor(conn, &errmsg))
 		return 0;				/* normal, successful exit */
 
-	goto set_error_result;		/* pqRowProcessor failed, report it */
+	/* pqRowProcessor failed, fall through to report it */
 
 advance_and_error:
-	/* Discard the failed message by pretending we read it */
-	conn->inStart += 5 + msgLength;
-
-set_error_result:
 
 	/*
 	 * Replace partially constructed result with an error result. First
@@ -855,6 +815,12 @@ set_error_result:
 	printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
 	pqSaveErrorResult(conn);
 
+	/*
+	 * Show the message as fully consumed, else pqParseInput3 will overwrite
+	 * our error with a complaint about that.
+	 */
+	conn->inCursor = conn->inStart + 5 + msgLength;
+
 	/*
 	 * Return zero to allow input parsing to continue.  Subsequent "D"
 	 * messages will be ignored until we get to end of data, since an error