diff --git a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/conf/Config.java b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/conf/Config.java
index 402b4be81..1c2cd1022 100644
--- a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/conf/Config.java
+++ b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/conf/Config.java
@@ -9,7 +9,7 @@ public class Config {
 
         public static String PATH = "";
 
-        public static int SAMPLING_RATE = 10000;
+        public static int SAMPLING_CYCLE = 1;
     }
 
     public static class Collector{
diff --git a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/sampling/SamplingService.java b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/sampling/SamplingService.java
index f1701dd37..a2bfa0a2d 100644
--- a/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/sampling/SamplingService.java
+++ b/skywalking-sniffer/skywalking-api/src/main/java/com/a/eye/skywalking/api/sampling/SamplingService.java
@@ -12,7 +12,7 @@ import com.a.eye.skywalking.trace.TraceSegment;
  * have been traced, but, considering CPU cost of serialization/deserialization, and network bandwidth, the agent do NOT
  * send all of them to collector, if SAMPLING is on.
  *
- * By default, SAMPLING is off, and {@link Config.Agent#SAMPLING_RATE} == 1000.
+ * By default, SAMPLING is off, and {@link Config.Agent#SAMPLING_CYCLE} == 1.
  *
  * @author wusheng
  */
@@ -20,26 +20,25 @@ public class SamplingService implements BootService {
     private static ILog logger = LogManager.getLogger(SamplingService.class);
 
     private volatile boolean on = false;
-    private volatile int rate = 0;
     private volatile int rollingSeed = 1;
 
     @Override
     public void bootUp() throws Throwable {
-        if (Config.Agent.SAMPLING_RATE == 10000) {
+        if (Config.Agent.SAMPLING_CYCLE == 1) {
+            this.on = false;
             return;
         }
-        if (Config.Agent.SAMPLING_RATE > 10000 || Config.Agent.SAMPLING_RATE < 1) {
-            throw new IllegalSamplingRateException("sampling rate should stay in (0, 10000].");
+        if (Config.Agent.SAMPLING_CYCLE < 1) {
+            throw new IllegalSamplingRateException("sampling cycle must greater than 0.");
         }
-        rate = 10000 / Config.Agent.SAMPLING_RATE;
-        on = true;
+        this.on = true;
 
-        logger.debug("The trace sampling is on, and the sampling rate is: {}", rate);
+        logger.debug("The trace sampling is on, and the sampling cycle is: {}", Config.Agent.SAMPLING_CYCLE);
     }
 
     public void trySampling(TraceSegment segment) {
         if (on) {
-            if (rollingSeed % rate != 0) {
+            if (rollingSeed % Config.Agent.SAMPLING_CYCLE != 0) {
                 segment.setSampled(false);
             }
             rollingSeed++;
diff --git a/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/api/sampling/SamplingServiceTest.java b/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/api/sampling/SamplingServiceTest.java
index 6fedcb121..d3d406cad 100644
--- a/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/api/sampling/SamplingServiceTest.java
+++ b/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/api/sampling/SamplingServiceTest.java
@@ -13,7 +13,7 @@ import org.junit.Test;
 public class SamplingServiceTest {
     @Test
     public void test50Percent(){
-        Config.Agent.SAMPLING_RATE = 5000;
+        Config.Agent.SAMPLING_CYCLE = 2;
         ServiceManager.INSTANCE.boot();
 
         TraceSegment segment = new TraceSegment();
@@ -30,7 +30,7 @@ public class SamplingServiceTest {
 
     @AfterClass
     public static void clear(){
-        Config.Agent.SAMPLING_RATE = 10000;
+        Config.Agent.SAMPLING_CYCLE = 1;
         ServiceManager.INSTANCE.boot();
     }
 }
diff --git a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/CallableStatementTracing.java b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/CallableStatementTracing.java
index 797908dcd..02975b3b2 100644
--- a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/CallableStatementTracing.java
+++ b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/CallableStatementTracing.java
@@ -24,6 +24,7 @@ public class CallableStatementTracing {
         try {
             Span span = ContextManager.createSpan(connectInfo.getDBType() + "/JDBI/CallableStatement/" + method);
             Tags.DB_TYPE.set(span, "sql");
+            Tags.SPAN_KIND.set(span, Tags.SPAN_KIND_CLIENT);
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
             Tags.DB_STATEMENT.set(span, sql);
             Tags.SPAN_LAYER.asDB(span);
diff --git a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/ConnectionTracing.java b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/ConnectionTracing.java
index 1b20172ac..ebb089921 100755
--- a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/ConnectionTracing.java
+++ b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/ConnectionTracing.java
@@ -24,6 +24,7 @@ public class ConnectionTracing {
         try {
             Span span = ContextManager.createSpan(connectInfo.getDBType() + "/JDBI/Connection/" + method);
             Tags.DB_TYPE.set(span, "sql");
+            Tags.SPAN_KIND.set(span, Tags.SPAN_KIND_CLIENT);
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
             Tags.DB_STATEMENT.set(span, sql);
             Tags.COMPONENT.set(span, connectInfo.getDBType());
diff --git a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
index 20f7fba3b..207bd91e7 100644
--- a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
+++ b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
@@ -23,6 +23,7 @@ public class PreparedStatementTracing {
         try {
             Span span = ContextManager.createSpan(connectInfo.getDBType() + "/JDBI/PreparedStatement/" + method);
             Tags.DB_TYPE.set(span, "sql");
+            Tags.SPAN_KIND.set(span, Tags.SPAN_KIND_CLIENT);
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
             Tags.DB_STATEMENT.set(span, sql);
             Tags.COMPONENT.set(span, connectInfo.getDBType());
diff --git a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/StatementTracing.java b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/StatementTracing.java
index f421e0ad0..f27a5033e 100644
--- a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/StatementTracing.java
+++ b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/StatementTracing.java
@@ -23,6 +23,7 @@ public class StatementTracing {
         try {
             Span span = ContextManager.createSpan(connectInfo.getDBType() + "/JDBI/Statement/" + method);
             Tags.DB_TYPE.set(span, "sql");
+            Tags.SPAN_KIND.set(span, Tags.SPAN_KIND_CLIENT);
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
             Tags.DB_STATEMENT.set(span, sql);
             Tags.COMPONENT.set(span, connectInfo.getDBType());