Change the order in which gpsmon sends packets to gpmmon

Before this commit, gpmmon expected to see QLOG packets before QUERYSEG packets.
Out of order packets were quietly dropped. This behavior was causing
intermittent test failure with the message: No segments for CPU skew
calculation.

This commit change the order of packet sends on gpsmon to fix these failures.
Signed-off-by: NJacob Champion <pchampion@pivotal.io>

gpAux/gpperfmon/src/gpmon/gpsmon.c

@@ -711,44 +711,47 @@ static void gx_gettcpcmd(SOCKET sock, short event, void* arg)
 		int count = 0;
 		apr_hash_t* query_cpu_table = NULL;
 
-		for (hi = apr_hash_first(0, querysegtab); hi; hi = apr_hash_next(hi))
+		for (hi = apr_hash_first(0, segtab); hi; hi = apr_hash_next(hi))
 		{
  			void* vptr;
 			apr_hash_this(hi, 0, 0, &vptr);
 			ppkt = vptr;
-			if (ppkt->header.pkttype != GPMON_PKTTYPE_QUERYSEG)
+			if (ppkt->header.pkttype != GPMON_PKTTYPE_SEGINFO)
 				continue;
 
+			/* fill in hostname */
+			strncpy(ppkt->u.seginfo.hostname, gx.hostname, sizeof(ppkt->u.seginfo.hostname) - 1);
+			ppkt->u.seginfo.hostname[sizeof(ppkt->u.seginfo.hostname) - 1] = 0;
+
 			TR2(("sending magic %x, pkttype %d\n", ppkt->header.magic, ppkt->header.pkttype));
 			send_smon_to_mon_pkt(sock, ppkt);
 			count++;
 		}
 
-		for (hi = apr_hash_first(0, segtab); hi; hi = apr_hash_next(hi))
+		for (hi = apr_hash_first(0, qdtab); hi; hi = apr_hash_next(hi))
 		{
  			void* vptr;
 			apr_hash_this(hi, 0, 0, &vptr);
 			ppkt = vptr;
-			if (ppkt->header.pkttype != GPMON_PKTTYPE_SEGINFO)
+			if (ppkt->header.pkttype != GPMON_PKTTYPE_QLOG)
 				continue;
-
-			/* fill in hostname */
-			strncpy(ppkt->u.seginfo.hostname, gx.hostname, sizeof(ppkt->u.seginfo.hostname) - 1);
-			ppkt->u.seginfo.hostname[sizeof(ppkt->u.seginfo.hostname) - 1] = 0;
-
 			TR2(("sending magic %x, pkttype %d\n", ppkt->header.magic, ppkt->header.pkttype));
 			send_smon_to_mon_pkt(sock, ppkt);
 			count++;
 		}
 
-
-		for (hi = apr_hash_first(0, qdtab); hi; hi = apr_hash_next(hi))
+		/*
+		 * QUERYSEG packets must be sent after QLOG packets so that gpmmon can
+		 * correctly populate its query_seginfo_hash.
+		 */
+		for (hi = apr_hash_first(0, querysegtab); hi; hi = apr_hash_next(hi))
 		{
  			void* vptr;
 			apr_hash_this(hi, 0, 0, &vptr);
 			ppkt = vptr;
-			if (ppkt->header.pkttype != GPMON_PKTTYPE_QLOG)
+			if (ppkt->header.pkttype != GPMON_PKTTYPE_QUERYSEG)
 				continue;
+
 			TR2(("sending magic %x, pkttype %d\n", ppkt->header.magic, ppkt->header.pkttype));
 			send_smon_to_mon_pkt(sock, ppkt);
 			count++;