diff --git a/src/main/java/org/tikv/common/log/SlowLog.java b/src/main/java/org/tikv/common/log/SlowLog.java
index e172a003462..007f3f1d736 100644
--- a/src/main/java/org/tikv/common/log/SlowLog.java
+++ b/src/main/java/org/tikv/common/log/SlowLog.java
@@ -22,5 +22,7 @@ public interface SlowLog {
 
   SlowLogSpan start(String name);
 
+  void setError(Throwable err);
+
   void log();
 }
diff --git a/src/main/java/org/tikv/common/log/SlowLogEmptyImpl.java b/src/main/java/org/tikv/common/log/SlowLogEmptyImpl.java
index 37e68237db5..5e76031f7c4 100644
--- a/src/main/java/org/tikv/common/log/SlowLogEmptyImpl.java
+++ b/src/main/java/org/tikv/common/log/SlowLogEmptyImpl.java
@@ -30,6 +30,9 @@ public SlowLogSpan start(String name) {
     return SlowLogSpanEmptyImpl.INSTANCE;
   }
 
+  @Override
+  public void setError(Throwable err) {}
+
   @Override
   public void log() {}
 }
diff --git a/src/main/java/org/tikv/common/log/SlowLogImpl.java b/src/main/java/org/tikv/common/log/SlowLogImpl.java
index 76ed4c922bf..3a722b90476 100644
--- a/src/main/java/org/tikv/common/log/SlowLogImpl.java
+++ b/src/main/java/org/tikv/common/log/SlowLogImpl.java
@@ -35,6 +35,7 @@ public class SlowLogImpl implements SlowLog {
   public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("HH:mm:ss.SSS");
 
   private final List<SlowLogSpan> slowLogSpans = new ArrayList<>();
+  private Throwable error = null;
 
   private final long startMS;
   private final long slowThresholdMS;
@@ -63,10 +64,15 @@ public synchronized SlowLogSpan start(String name) {
     return slowLogSpan;
   }
 
+  @Override
+  public void setError(Throwable err) {
+    this.error = err;
+  }
+
   @Override
   public void log() {
     long currentMS = System.currentTimeMillis();
-    if (slowThresholdMS >= 0 && currentMS - startMS > slowThresholdMS) {
+    if (error != null || (slowThresholdMS >= 0 && currentMS - startMS > slowThresholdMS)) {
       logger.warn("SlowLog:" + getSlowLogString(currentMS));
     }
   }
@@ -77,6 +83,9 @@ private String getSlowLogString(long currentMS) {
     jsonObject.addProperty("start", DATE_FORMAT.format(startMS));
     jsonObject.addProperty("end", DATE_FORMAT.format(currentMS));
     jsonObject.addProperty("duration", (currentMS - startMS) + "ms");
+    if (error != null) {
+      jsonObject.addProperty("error", error.getMessage());
+    }
 
     for (Map.Entry<String, String> entry : properties.entrySet()) {
       jsonObject.addProperty(entry.getKey(), entry.getValue());
diff --git a/src/main/java/org/tikv/raw/RawKVClient.java b/src/main/java/org/tikv/raw/RawKVClient.java
index d68e162912d..76ef92581a1 100644
--- a/src/main/java/org/tikv/raw/RawKVClient.java
+++ b/src/main/java/org/tikv/raw/RawKVClient.java
@@ -158,6 +158,7 @@ private void put(ByteString key, ByteString value, long ttl, boolean atomic) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -214,6 +215,7 @@ public ByteString putIfAbsent(ByteString key, ByteString value, long ttl) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -279,6 +281,7 @@ private void batchPut(Map<ByteString, ByteString> kvPairs, long ttl, boolean ato
       RAW_REQUEST_SUCCESS.labels(label).inc();
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -321,6 +324,7 @@ public ByteString get(ByteString key) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -355,6 +359,7 @@ public List<KvPair> batchGet(List<ByteString> keys) {
       return result;
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -401,6 +406,7 @@ private void batchDelete(List<ByteString> keys, boolean atomic) {
       return;
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -443,6 +449,7 @@ public Long getKeyTTL(ByteString key) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -547,6 +554,7 @@ public List<KvPair> scan(ByteString startKey, ByteString endKey, int limit, bool
       return result;
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -635,6 +643,7 @@ public List<KvPair> scan(ByteString startKey, ByteString endKey, boolean keyOnly
       return result;
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -717,6 +726,7 @@ private void delete(ByteString key, boolean atomic) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();