How do I connect to a TencentDB for MySQL instance?
You can connect to a TencentDB for MySQL instance in the following ways:
Private Network Connection: Use a CVM instance to directly connect to the private network address of the TencentDB instance. This connection method utilizes high-speed private network with low latency. The CVM instance and the database must be under the same account and in the same VPC (ensuring they are in the same region), or both in the classic network.
Public network connection: If you cannot access the private network, you can connect to your TencentDB for MySQL instance at its public network address. The public network address needs to be manually enabled. It can be viewed on the instance details page in the TencentDB for MySQL console and can be disabled if no longer needed.
What should I do if the connection to TencentDB for MySQL failed?
Failure to connect to TencentDB for MySQL from CVM or local computer
1. Use the diagnosis tool to locate the causes
The TencentDB for MySQL console provides a one-click connectivity check tool to help you locate the causes of connection failures. Then, you can make changes according to the prompts and retry to connect to the instance.
2. Locate the causes by yourself
If you cannot locate the cause of the problem with the one-click connectivity check tool, you can try to locate the cause by yourself by referring to the failure causes as described in Instance Connection Failure.
Failure to connect to TencentDB for MySQL from DMC
1. Ensure that the login account's host restrictions have authorized all IPs of the DMC server in the region. For authorization, see Modify Authorized Host Addresses. You can also use the wildcard % to allow all IPs and rely solely on security groups to restrict database access sources.
2. If the IPs have been authorized, the issue may be caused by an incorrect password. Please re-enter the correct password, or you can reset the password or create a temporary account with the required permissions.
How do I query the private/public network address?
Log in to the TencentDB for MySQL console, click an instance ID in the instance list to enter the instance details page, and view the private/public network addresses.
How do I enable the public network address?
Log in to the TencentDB for MySQL console, click an instance ID in the instance list to enter the instance details page, and enable the public network address in Public Network Address.
What should I do if I have slow access over the public network?
We recommend that you use the private network. This connection method uses the high-speed private network with a low delay. For more information, see Connecting to MySQL Instance.
Can I use a CVM instance to connect to the private network address of a TencentDB for MySQL instance?
1. The following conditions must be met before you can use private network access:
The two instances must be in the same VPC in the same region, or both in the classic network.
2. You can check whether they are in the same VPC or both in the classic network in the following ways:
You can log in to the CVM console, and view the network information of a CVM instance in the instance list or on the instance details page.
You can log in to the TencentDB for MySQL console, and view the network information of a MySQL instance in the instance list or on the instance details page.
For more information, see Network Types/VPC Determination Methods.
What should I do if I can't use a CVM instance to connect to the private network address of a TencentDB for MySQL instance?
We recommend that you use the one-click connectivity check tool to troubleshoot the problem first and then find the corresponding solution in Instance Connection Failure according to the check report.
My CVM and TencentDB for MySQL instances are in different regions (such as Guangzhou and Shanghai, respectively). Can I use the private network for connection?
No. For solutions, see Instance Connection Failure > CVM and MySQL in different regions and different VPCs.
My CVM and TencentDB for MySQL instances are in different AZs (such as Shanghai Zone 2 and Shanghai Zone 1, respectively) in the same region. Can I use the private network for connection?
Even if the CVM and TencentDB for MySQL instances are in the same region, they may be in different VPCs.
If they are in different AZs in the same VPC, they can interconnect over the private network.
If they are in different VPCs (such as VPC1 and VPC2, respectively), they cannot interconnect over the private network. For solutions, see Instance Connection Failure > CVM and MySQL in the same region but different VPCs.
Can I use a CVM instance to connect to a TencentDB for MySQL instance directly over the private network when they are under different accounts?
You cannot directly connect via the private network, but you can use Cloud Connect Network to achieve cross-account private network connections.
The verification with telnet found that the network and port connectivity of the TencentDB instance was good, but an error was reported when I tried to log in to it on the command line in the CVM instance. What should I do?
If you encounter the message "ERROR 1045(28000): Access denied for user...", please ensure that you have entered the correct TencentDB account and password. If you have forgotten your password, refer to Resetting Password. If the error persists after entering the correct information, check if your instance has IP restrictions for connections in the TencentDB for MySQL console under Instance Management > Database Management > Account Management.
If "ERROR 1040(00000):Too many connections" is displayed, it indicates that the number of connections to the TencentDB instance has exceeded the limit. Common causes and solutions are as follows:
i. There are too many sleeping threads. We recommend that you lower the values of
wait_timeout and interactive_timeout in the console.
ii. Slow queries heaped up. The long_query_time parameter is 10s by default. We recommend that you change it to 1–2s and then observe slow query logs.
iii. If there are few sleeping threads and no slow queries heaped up, we recommend that you increase the value of the max_connections parameter in the console.If "ERROR 2003 (HY000): Can't connect to MySQL server..." is displayed, check whether the instance IP and port entered are correct. If the error persists after you enter the correct information, check the security group policies of the instance in the console to verify whether the CVM instance has the permission to connect to the database. For more information, see TencentDB Security Group Management.
If the connectivity test fails during data migration, check whether the security policy allows the prompted migration proxy IP.
Check the
init_connect parameter (if set), such as mysql>set global init_connect='insert into db_monitor.accesslog(thread_id,log_time,localname,matchname) values(connection_id(),now(),user(),current_user())';.
This means that each connection to the database by each non-super-privileged user will insert an entry into the db_monitor.accesslog table. Once there are uncommitted transactions or relevant lock waits in the table, then insert into db_monitor.accesslog operations will be jammed, causing all connections by non-super-privileged users to be stuck and affecting the normal use of TencentDB. Therefore, configure the init_connect parameter with caution.