Drop server support for FE/BE protocol version 1.0.

While this isn't a lot of code, it's been essentially untestable for
a very long time, because libpq doesn't support anything older than
protocol 2.0, and has not since release 6.3.  There's no reason to
believe any other client-side code still uses that protocol, either.

Discussion: <2661.1475849167@sss.pgh.pa.us>

src/backend/access/common/printtup.c

@@ -229,9 +229,7 @@ SendRowDescriptionMessage(TupleDesc typeinfo, List *targetlist, int16 *formats)
 		atttypid = getBaseTypeAndTypmod(atttypid, &atttypmod);
 		pq_sendint(&buf, (int) atttypid, sizeof(atttypid));
 		pq_sendint(&buf, attrs[i]->attlen, sizeof(attrs[i]->attlen));
-		/* typmod appears in protocol 2.0 and up */
-		if (proto >= 2)
-			pq_sendint(&buf, atttypmod, sizeof(atttypmod));
+		pq_sendint(&buf, atttypmod, sizeof(atttypmod));
 		/* format info appears in protocol 3.0 and up */
 		if (proto >= 3)
 		{

src/backend/commands/copy.c

@@ -353,7 +353,7 @@ SendCopyBegin(CopyState cstate)
 		pq_endmessage(&buf);
 		cstate->copy_dest = COPY_NEW_FE;
 	}
-	else if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
+	else
 	{
 		/* old way */
 		if (cstate->binary)
@@ -365,18 +365,6 @@ SendCopyBegin(CopyState cstate)
 		pq_startcopyout();
 		cstate->copy_dest = COPY_OLD_FE;
 	}
-	else
-	{
-		/* very old way */
-		if (cstate->binary)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("COPY BINARY is not supported to stdout or from stdin")));
-		pq_putemptymessage('B');
-		/* grottiness needed for old COPY OUT protocol */
-		pq_startcopyout();
-		cstate->copy_dest = COPY_OLD_FE;
-	}
 }
 
 static void
@@ -399,7 +387,7 @@ ReceiveCopyBegin(CopyState cstate)
 		cstate->copy_dest = COPY_NEW_FE;
 		cstate->fe_msgbuf = makeStringInfo();
 	}
-	else if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
+	else
 	{
 		/* old way */
 		if (cstate->binary)
@@ -411,18 +399,6 @@ ReceiveCopyBegin(CopyState cstate)
 		pq_startmsgread();
 		cstate->copy_dest = COPY_OLD_FE;
 	}
-	else
-	{
-		/* very old way */
-		if (cstate->binary)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("COPY BINARY is not supported to stdout or from stdin")));
-		pq_putemptymessage('D');
-		/* any error in old protocol will make us lose sync */
-		pq_startmsgread();
-		cstate->copy_dest = COPY_OLD_FE;
-	}
 	/* We *must* flush here to ensure FE knows it can send. */
 	pq_flush();
 }

src/backend/tcop/dest.c

@@ -218,8 +218,8 @@ NullCommand(CommandDest dest)
 /* ----------------
  *		ReadyForQuery - tell dest that we are ready for a new query
  *
- *		The ReadyForQuery message is sent in protocol versions 2.0 and up
- *		so that the FE can tell when we are done processing a query string.
+ *		The ReadyForQuery message is sent so that the FE can tell when
+ *		we are done processing a query string.
  *		In versions 3.0 and up, it also carries a transaction state indicator.
  *
  *		Note that by flushing the stdio buffer here, we can avoid doing it
@@ -241,7 +241,7 @@ ReadyForQuery(CommandDest dest)
 				pq_sendbyte(&buf, TransactionBlockStatusCode());
 				pq_endmessage(&buf);
 			}
-			else if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
+			else
 				pq_putemptymessage('Z');
 			/* Flush output at end of cycle in any case. */
 			pq_flush();

src/backend/tcop/postgres.c

@@ -3768,8 +3768,7 @@ PostgresMain(int argc, char *argv[],
 	/*
 	 * Send this backend's cancellation info to the frontend.
 	 */
-	if (whereToSendOutput == DestRemote &&
-		PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
+	if (whereToSendOutput == DestRemote)
 	{
 		StringInfoData buf;
 

src/include/libpq/pqcomm.h

@@ -107,7 +107,7 @@ typedef struct
 
 /* The earliest and latest frontend/backend protocol version supported. */
 
-#define PG_PROTOCOL_EARLIEST	PG_PROTOCOL(1,0)
+#define PG_PROTOCOL_EARLIEST	PG_PROTOCOL(2,0)
 #define PG_PROTOCOL_LATEST		PG_PROTOCOL(3,0)
 
 typedef uint32 ProtocolVersion; /* FE/BE protocol version number */