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 a5f3dd6f3bb..7ffd1ed0514 100644
--- a/src/main/java/org/tikv/raw/RawKVClient.java
+++ b/src/main/java/org/tikv/raw/RawKVClient.java
@@ -151,6 +151,7 @@ public void put(ByteString key, ByteString value, long ttl) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -249,6 +250,7 @@ public void compareAndSet(
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -291,6 +293,7 @@ public void batchPut(Map<ByteString, ByteString> kvPairs, long ttl) {
       RAW_REQUEST_SUCCESS.labels(label).inc();
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -333,6 +336,7 @@ public Optional<ByteString> get(ByteString key) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -367,6 +371,7 @@ 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();
@@ -400,6 +405,7 @@ public void batchDelete(List<ByteString> keys) {
       return;
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -442,6 +448,7 @@ public Optional<Long> getKeyTTL(ByteString key) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();
@@ -589,6 +596,7 @@ 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();
@@ -677,6 +685,7 @@ 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();
@@ -745,6 +754,7 @@ public void delete(ByteString key) {
       }
     } catch (Exception e) {
       RAW_REQUEST_FAILURE.labels(label).inc();
+      slowLog.setError(e);
       throw e;
     } finally {
       requestTimer.observeDuration();