#1476 add size check and change disable flag checked (#1511)

Author: sunsun314

src/main/java/com/actiontech/dble/backend/datasource/PhysicalDNPoolSingleWH.java

@@ -182,7 +182,7 @@ public Map<Integer, PhysicalDatasource[]> getStandbyReadSourcesMap() {
     @Override
     void getRWBalanceCon(String schema, boolean autocommit, ResponseHandler handler, Object attachment) throws Exception {
         PhysicalDatasource theNode = getRWBalanceNode();
-        if (theNode.getConfig().isDisabled()) {
+        if (theNode.isDisabled()) {
             if (this.getReadSources().values().size() > 0) {
                 theNode = this.getReadSources().values().iterator().next()[0];
             } else {

src/main/java/com/actiontech/dble/config/util/SchemaWriteJob.java

@@ -78,7 +78,7 @@ private void changeHostInfo(DataHost dh, PhysicalDNPoolSingleWH physicalDNPoolSi
         }
 
         List<ReadHost> newReadList = new ArrayList<ReadHost>();
-        if (physicalDNPoolSingleWH.getReadSourceAll() != null) {
+        if (physicalDNPoolSingleWH.getReadSourceAll().size() > 0) {
             for (PhysicalDatasource rs : physicalDNPoolSingleWH.getReadSourceAll().get(0)) {
                 ReadHost r = new ReadHost();
                 r.setDisabled("" + rs.isDisabled());