[TD-3572]<enhance>: response out of dnodes if #dnodes <= maxDbReplica

src/mnode/inc/mnodeDb.h

@@ -31,6 +31,7 @@ enum _TSDB_DB_STATUS {
 int32_t mnodeInitDbs();
 void    mnodeCleanupDbs();
 int64_t mnodeGetDbNum();
+int32_t mnodeGetDbMaxReplica();
 SDbObj *mnodeGetDb(char *db);
 SDbObj *mnodeGetDbByTableName(char *db);
 void *  mnodeGetNextDb(void *pIter, SDbObj **pDb);

src/mnode/src/mnodeDb.c

@@ -74,6 +74,24 @@ int64_t mnodeGetDbNum() {
   return sdbGetNumOfRows(tsDbSdb);
 }
 
+int32_t mnodeGetDbMaxReplica() {
+  int32_t maxReplica = 0;
+  SDbObj *pDb = NULL;
+  void   *pIter = NULL;
+
+  while (1) {
+    pIter = mnodeGetNextDb(pIter, &pDb);
+    if (pDb == NULL) break;
+
+    if (pDb->cfg.replications > maxReplica)
+      maxReplica = pDb->cfg.replications;
+
+    mnodeDecDbRef(pDb);
+  }
+
+  return maxReplica;
+}
+
 static int32_t mnodeDbActionInsert(SSdbRow *pRow) {
   SDbObj *pDb = pRow->pObj;
   SAcctObj *pAcct = mnodeGetAcct(pDb->acct);

src/mnode/src/mnodeDnode.c

@@ -29,6 +29,7 @@
 #include "mnodeDef.h"
 #include "mnodeInt.h"
 #include "mnodeDnode.h"
+#include "mnodeDb.h"
 #include "mnodeMnode.h"
 #include "mnodeSdb.h"
 #include "mnodeShow.h"
@@ -745,6 +746,14 @@ static int32_t mnodeDropDnodeByEp(char *ep, SMnodeMsg *pMsg) {
     return TSDB_CODE_MND_NO_REMOVE_MASTER;
   }
 
+  int32_t maxReplica = mnodeGetDbMaxReplica();
+  int32_t dnodesNum = mnodeGetDnodesNum();
+  if (dnodesNum <= maxReplica) {
+    mError("dnode:%d, can't drop dnode:%s, #dnodes: %d, replia: %d", pDnode->dnodeId, ep, dnodesNum, maxReplica);
+    mnodeDecDnodeRef(pDnode);
+    return TSDB_CODE_MND_NO_ENOUGH_DNODES;
+  }
+
   mInfo("dnode:%d, start to drop it", pDnode->dnodeId);
 
   int32_t code = bnDropDnode(pDnode);

tests/script/unique/cluster/balance2.sim

@@ -338,10 +338,6 @@ system sh/exec.sh -n dnode1 -s stop  -x SIGINT
 print stop dnode1 and sleep 3000
 sleep 3000
 
-sql drop dnode $hostname1
-print drop dnode1 and sleep 9000
-sleep 9000
-
 sql show mnodes
 $dnode1Role = $data2_1
 $dnode4Role = $data2_4
@@ -357,6 +353,25 @@ endi
 print ============================== step6.1
 system sh/exec.sh -n dnode1 -s start
 
+$x = 0
+step6.1:
+	$x = $x + 1
+	sleep 1000
+	if $x == 10 then
+		return -1
+	endi
+
+sql show dnodes
+print dnode1 $data4_1
+
+if $data4_1 != ready then
+  goto step6.1
+endi
+
+sql drop dnode $hostname1
+print drop dnode1 and sleep 9000
+sleep 9000
+
 $x = 0
 show6: 
 	$x = $x + 1

tests/script/unique/dnode/remove1.sim

@@ -97,7 +97,6 @@ if $data2_2 != 3 then
 endi
 
 print ========== step3
-sql drop dnode $hostname2
 
 $x = 0
 show3: 
@@ -114,6 +113,7 @@ print dnode2 openVnodes $data2_2
 print ========== step4
 sql create dnode $hostname3
 system sh/exec.sh -n dnode3 -s start
+sql drop dnode $hostname2
 
 $x = 0
 show4: 
@@ -224,4 +224,4 @@ system sh/exec.sh -n dnode4 -s stop  -x SIGINT
 system sh/exec.sh -n dnode5 -s stop  -x SIGINT
 system sh/exec.sh -n dnode6 -s stop  -x SIGINT
 system sh/exec.sh -n dnode7 -s stop  -x SIGINT
-system sh/exec.sh -n dnode8 -s stop  -x SIGINT
+system sh/exec.sh -n dnode8 -s stop  -x SIGINT

tests/script/unique/dnode/remove2.sim

@@ -98,7 +98,6 @@ endi
 
 print ========== step3
 system sh/exec.sh -n dnode2 -s stop -x SIGINT
-sql drop dnode $hostname2
 
 sql show dnodes
 print dnode1 openVnodes $data2_1
@@ -128,6 +127,26 @@ endi
 print ============ step 4.1
 system sh/exec.sh -n dnode2 -s start
 
+$x = 0
+step4.1:
+	$x = $x + 1
+	sleep 1000
+	if $x == 10 then
+		return -1
+	endi
+
+sql show dnodes
+print dnode1 $data4_1
+print dnode2 $data4_2
+print dnode3 $data4_3
+print dnode4 $data4_4
+
+if $data4_2 != ready then
+  goto step4.1
+endi
+
+sql drop dnode $hostname2
+
 $x = 0
 show4: 
 	$x = $x + 1