fix storage-jdbc isExists not set dbname (#5786)

* fix null catalog

* update CHANGES.md

CHANGES.md

@@ -26,6 +26,7 @@ Release Notes.
 * Improve the queryable tags generation. Remove the duplicated tags to reduce the storage payload.
 * Fix the excessive timeout period set by the kubernetes-client.
 * Fix deadlock problem when using elasticsearch-client-7.0.0.
+* Fix storage-jdbc isExists not set dbname.
 
 #### UI
 

oap-server/server-storage-plugin/storage-jdbc-hikaricp-plugin/src/main/java/org/apache/skywalking/oap/server/storage/plugin/jdbc/mysql/MySQLTableInstaller.java

@@ -58,7 +58,7 @@ public class MySQLTableInstaller extends H2TableInstaller {
         TableMetaInfo.addModel(model);
         JDBCHikariCPClient h2Client = (JDBCHikariCPClient) client;
         try (Connection conn = h2Client.getConnection()) {
-            try (ResultSet rset = conn.getMetaData().getTables(null, null, model.getName(), null)) {
+            try (ResultSet rset = conn.getMetaData().getTables(conn.getCatalog(), null, model.getName(), null)) {
                 if (rset.next()) {
                     return true;
                 }