:original_name: ALM-45587.html

.. _ALM-45587:

ALM-45587 IoTDBServer GC Duration Exceeds the Threshold
=======================================================

Description
-----------

The system checks the GC duration of the IoTDBServer process every 60 seconds. This alarm is generated when the GC duration exceeds the threshold (12 seconds by default) for three consecutive times. You can choose **O&M** > **Alarm** > **Threshold Configuration** > *Name of the desired cluster* > **IoTDB** > **GC** > **Total GC duration of IoTDBServer process (IoTDBServer)** to change the threshold. This alarm is cleared when the GC duration is less than the threshold.

Attribute
---------

======== ============== ==========
Alarm ID Alarm Severity Auto Clear
======== ============== ==========
45587    Major          Yes
======== ============== ==========

Parameters
----------

+-------------------+---------------------------------------------------------+
| Name              | Meaning                                                 |
+===================+=========================================================+
| Source            | Specifies the cluster for which the alarm is generated. |
+-------------------+---------------------------------------------------------+
| ServiceName       | Specifies the service for which the alarm is generated. |
+-------------------+---------------------------------------------------------+
| RoleName          | Specifies the role for which the alarm is generated.    |
+-------------------+---------------------------------------------------------+
| HostName          | Specifies the host for which the alarm is generated.    |
+-------------------+---------------------------------------------------------+
| Trigger Condition | Specifies the threshold for triggering the alarm.       |
+-------------------+---------------------------------------------------------+

Impact on the System
--------------------

A long GC duration of the IoTDBServer process may interrupt the services.

Possible Causes
---------------

The heap memory of the IoTDBServer process is overused or inappropriately allocated, causing frequent occurrence of the GC process.

Procedure
---------

**Check the GC duration.**

#. Log in to FusionInsight Manager and choose **O&M**. In the navigation pane on the left, choose **Alarm** > **Alarms**. On the page that is displayed, locate the row containing the alarm whose **Alarm ID** is **45587**, view the role name in **Location**, and check the instance IP address.

#. Choose **Cluster** > *Name of the desired cluster* > **Service** > **IoTDB** > **Instance**. Click the IoTDBServer for which the alarm is generated to go to **Dashboard**. Click the drop-down list in the upper right corner of the chart area and choose **Customize** > **GC**. In the dialog box that is displayed, select **Garbage Collection (GC) Time of IoTDBServer**, and click **OK**. Check whether the GC time of the IoTDBServer process is greater than 12 seconds.

   -  If yes, go to :ref:`3 <alm-45587__li1141514131368>`.
   -  If no, go to :ref:`5 <alm-45587__li4749473185459>`.

#. .. _alm-45587__li1141514131368:

   Choose **Cluster** > *Name of the desired cluster* > **Service** > **IoTDB** > **Configuration**, click **All Configurations**, choose **IoTDBServer** > **System**, and increase the value of **-Xmx** in the **GC_OPTS** parameter.

   .. note::

      -  The default value of -**Xmx** is **2G**.
      -  If this alarm is occasionally generated, increase the value by 0.5 times. If this alarm is frequently generated, double the value.
      -  In the case of large service volume and high service concurrency, you are advised to add instances.

#. Check whether the alarm is cleared.

   -  If yes, no further action is required.
   -  If no, go to :ref:`5 <alm-45587__li4749473185459>`.

**Collect the fault information.**

5. .. _alm-45587__li4749473185459:

   On FusionInsight Manager, choose **O&M**. In the navigation pane on the left, choose **Log** > **Download**.

6. Expand the **Service** drop-down list, select **IoTDB** for the target cluster, and click **OK**.

7. Click |image1| in the upper right corner, and set **Start Date** and **End Date** for log collection to 30 minutes ahead of and after the alarm generation time respectively. Then, click **Download**.

8. Contact O&M personnel and provide the collected logs.

Alarm Clearing
--------------

This alarm is automatically cleared after the fault is rectified.

Related Information
-------------------

None

.. |image1| image:: /_static/images/en-us_image_0000001532448186.png
