Troubleshoot resource usage and performance issues

Available in Classic and VPC

In using Cloud DB for MySQL, you may encounter the following problems. View the causes and solutions of problems and take proper action:

Data storage size decreased after restarting MySQL Server (VPC)

The size of data storage decreased after restarting MySQL Server.

Cause

MySQL Server may increase the Temporary Tablespace storage size if you use long transactions, which may cause it to display a decreased capacity MySQL Server. This is normal, and upon restarting the MySQL Server, the temporary storage space will be returned.

Solution

Check that tie size of Temporary Tablespace storage has not increased.

You can monitor whether the storage is increasing beyond a certain size by registering an event that monitors the size of storage. To register an event, follow these steps:

1. In the VPC environment of the NAVER Cloud Platform console, navigate to > Services > Management & Governance > Cloud Insight > Configuration > Event Rule.
2. Click [Create Event Rules]
3. Select Cloud DB for MySQL (VPC) and click [Next].
4. When the Set monitored targets screen appears, select All resources > Monitored targets and click [Next].
5. When the Set monitored item screen appears, select Full View > disk_mysql_used metric and click [Next].
6. When the Set action screen appears, select notice recipient and click [Next].
7. Enter the name of rule, and click [Create].

Data storage size decreased after restarting MySQL Server (Classic)

The size of data storage decreased after restarting MySQL Server.

Cause

MySQL Server may increase the Temporary Tablespace storage size if you use long transactions, which may cause it to display a decreased capacity MySQL Server. This is normal, and upon restarting the MySQL Server, the temporary storage space will be returned.

Solution

Check that tie size of Temporary Tablespace storage has not increased.

You can monitor whether the storage is increasing beyond a certain size by registering an event that monitors the size of storage. To register an event, follow these steps:

1. In the Classic environment of the NAVER Cloud Platform console, navigate to > Services > Database > Cloud DB for MySQL > Event.
2. Select DB Server from [Event settings status] tap and click [Set event].
3. When the Select DB server page appears, check the information of the Redis server to set up and click [Set event items].
4. When the Set notification items page appears, add Filesystem and click [Next].
5. When the Set notification recipients page appears, add the recipients and click [Next].
6. After checking the event information and click [OK].

Memory usage increased

Memory usage keeps increasing.

Cause

To increase performance, Cloud DB for MySQL service is designed to increase memory by around 90% as user data grows. This is to process as much data as possible in memory for faster response times, and it is normal for usage to increase to about 90% of the actual memory size.

Solution

As explained in Cause, it is common that memory usage increases. However, if you want to lower it, adjust the size of buffer pool.
The following shows how to adjust the size of buffer pool:

1. From the NAVER Cloud Platform console, navigate to > Services > Database > Cloud DB for MySQL,.
2. Select DB to adjust memory usage from DB Server and click [Manage DB] > Manage DB Config.
3. From Config Name, select Innodb_buffer_pool_size and edit the value of Config Value. Click [Add].
4. Click [Save].

DB performance issues and response delays

Issue in DB performance occurs.
There is a delay in DB response.

Cause

Depending on the situation, a variety of causes may exist. Check the solutions.

Solution

You need to check for indicator changes. To check for indicator changes, from the NAVER Cloud Platform console, click Services > Database > Cloud DB for MySQL > Monitoring, and [DB Dashboard], in order.

The following are the indicator items you should monitor and the items you should check as the indicator changes:

Connections
The number of running should be below 10 for stable response. If it's too high, you need to improve Query tuning and service logic. To see Query that is currently executing, click DB Server > Details > [PROCESS LIST].

Database activity
Check for spikes in DB request. If so, check for service events.

Slow Query
If the number of Slow Query occurred, check for Slow Query from Monitoring > DB Logs.

Row Access
The number of times table row was read during executing Query (in seconds). If this is high (millions or more), the index is not working efficiently. Check for Query.

High CPU usage

CPU usage is high.

Cause

CPU usage may be seen as high by service queries.

Solution

From the NAVER Cloud Platform console, click Services > Database > Cloud DB for MySQL > Monitoring in order and [DB Dashboard] to check the following:

• Volume of query request

  • Check Database Activity to see if Query has increased than usual.
  • If seen more queries, check for service traffic changes.

• Check Slow query

  • Check Slow Query to see if there’s any Slow query occurred at that time. If the query increased, check for increased requests volume, query plan, and data change.
  • To check Slow query during the time of problem, from the NAVER Cloud Platform console, click Services > Database > Cloud DB for MySQL > Monitoring > [DB Logs].

• Check Running session

  • Check Connections if the value of running has increased. If running value increased, check if it is a query causing increased requests volume and DB Lock.
  • To check Running query during the time of problem, from the NAVER Cloud Platform console, click Services > Database > Cloud DB for MySQL > Monitoring > [Query Timeline].

• Check Row Accesses

  • Check if the value of Row Accesses has increased.
  • If the value increased, check for increased requests volume, query plan, and data change.