Take Adrian Cole ’s advice, remove http prefix of tag. Maybe still need some improvements.

skywalking-commons/skywalking-trace/src/main/java/com/a/eye/skywalking/trace/tag/Tags.java

@@ -13,38 +13,48 @@ public final class Tags {
     }
 
     /**
-     *  HTTP_URL records the url of the incoming request.
+     *  URL records the url of the incoming request.
      */
-    public static final StringTag HTTP_URL = new StringTag("http.url");
+    public static final StringTag URL = new StringTag("url");
 
     /**
-     *  HTTP_STATUS records the http status code of the response.
+     *  STATUS_CODE records the http status code of the response.
      */
-    public static final IntTag HTTP_STATUS = new IntTag("http.status_code");
+    public static final IntTag STATUS_CODE = new IntTag("status_code");
 
     /**
-     *
+     *  SPAN_KIND hints at the relationship between spans, e.g. client/server.
      */
     public static final StringTag SPAN_KIND = new StringTag("span.kind");
 
+    /**
+     * A constant for setting the span kind to indicate that it represents a server span.
+     */
+    public static final String SPAN_KIND_SERVER = "server";
+
+    /**
+     * A constant for setting the span kind to indicate that it represents a client span.
+     */
+    public static final String SPAN_KIND_CLIENT = "client";
+
     /**
      *  SPAN_LAYER represents the kind of span.
-     *  e.g. db=database, rpc=Remote Procedure Call, nosql=something like redis/memcache
+     *  e.g. db=database; rpc=Remote Procedure Call Framework, like motan, thift; nosql=something like redis/memcache
      */
     public static final class SPAN_LAYER {
         private static StringTag SPAN_LAYER_TAG = new StringTag("span.layer");
 
-        private static final String DB_LAYER = "db";
-        private static final String RPC_LAYER = "rpc";
+        private static final String RDB_LAYER = "rda";
+        private static final String RPC_FRAMEWORK_LAYER = "rpc";
         private static final String NOSQL_LAYER = "nosql";
         private static final String HTTP_LAYER = "http";
 
         public static void asDBAccess(Span span){
-            SPAN_LAYER_TAG.set(span, DB_LAYER);
+            SPAN_LAYER_TAG.set(span, RDB_LAYER);
         }
 
-        public static void asRPC(Span span){
-            SPAN_LAYER_TAG.set(span, RPC_LAYER);
+        public static void asRPCFramework(Span span){
+            SPAN_LAYER_TAG.set(span, RPC_FRAMEWORK_LAYER);
         }
 
         public static void asNoSQL(Span span){
@@ -60,11 +70,11 @@ public final class Tags {
         }
 
         public static boolean isDBAccess(Span span){
-            return DB_LAYER.equals(get(span));
+            return RDB_LAYER.equals(get(span));
         }
 
-        public static boolean isRPC(Span span){
-            return RPC_LAYER.equals(get(span));
+        public static boolean isRPCFramework(Span span){
+            return RPC_FRAMEWORK_LAYER.equals(get(span));
         }
 
         public static boolean isNoSQL(Span span){
@@ -98,7 +108,7 @@ public final class Tags {
     public static final StringTag DB_URL = new StringTag("db.url");
 
     /**
-     *  DB_SQL records the sql statement of the database access.
+     *  DB_STATEMENT records the sql statement of the database access.
      */
-    public static final StringTag DB_SQL = new StringTag("db.statement");
+    public static final StringTag DB_STATEMENT = new StringTag("db.statement");
 }

skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/SpanTestCase.java

@@ -41,10 +41,10 @@ public class SpanTestCase {
         Tags.COMPONENT.set(span1, "Spring");
         Tags.PEER_HOST.set(span1, ipToInt("127.0.0.1"));
         Tags.ERROR.set(span1, true);
-        Tags.HTTP_STATUS.set(span1, 302);
-        Tags.HTTP_URL.set(span1, "http://127.0.0.1/serviceA");
+        Tags.STATUS_CODE.set(span1, 302);
+        Tags.URL.set(span1, "http://127.0.0.1/serviceA");
         Tags.DB_URL.set(span1, "jdbc:127.0.0.1:user");
-        Tags.DB_SQL.set(span1, "select * from users");
+        Tags.DB_STATEMENT.set(span1, "select * from users");
 
         Map<String, Object> tags = span1.getTags();
         Assert.assertEquals(8, tags.size());

skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java

@@ -19,7 +19,7 @@ public class PreparedStatementTracing {
         try {
             Tags.SPAN_LAYER.asDBAccess(span);
             Tags.DB_URL.set(span, connectInfo);
-            Tags.DB_SQL.set(span, sql);
+            Tags.DB_STATEMENT.set(span, sql);
             return exec.exe(realStatement, sql);
         } catch (SQLException e) {
             span.log(e);