Connection Management Connection Volume Management To control the maximum number of clients the server permits to connect simultaneously, set the max_connections  system variable at server startup or at runtime. It may be necessary to increase max_connections  if more clients attempt to connect simultaneously then the server is configured to handle (see Section B.3.2.5, “Too many connections” ). If the server refuses a connection because the max_connections  limit is reached, it increments the  Connection_errors_max_connections  status variable. mysqld  actually permits  max_connections  + 1 client connections. The extra connection is reserved for use by accounts that have the  CONNECTION_ADMIN  privilege (or the deprecated  SUPER  privilege). By granting the privilege to administrators and not to normal users (who should not need it), an administrator can connect to the server and use  SHOW PROCESSLIST  to diagnose problems even if the maximum number of unprivileged clients are connected. See Section 13.7.7.29, “SHOW PROCESSLIST Statement” . As of MySQL 8.0.14, the server also permits administrative connections on an administrative network interface, which you can set up using a dedicated IP address and port. See Section 5.1.12.2, “Administrative Connection Management” . The Group Replication plugin interacts with MySQL Server using internal sessions to perform SQL API operations. In releases to MySQL 8.0.18, these sessions count towards the client connections limit specified by the  max_connections  server system variable. In those releases, if the server has reached the  max_connections  limit when Group Replication is started or attempts to perform an operation, the operation is unsuccessful and Group Replication or the server itself might stop. From MySQL 8.0.19, Group Replication’s internal sessions are handled separately from client connections, so they do not count towards the  max_connections  limit and are not refused if the server has reached this limit. The maximum number of client connections MySQL supports (that is, the maximum value to which max_connections  can be set) depends on several factors: Linux or Solaris should be able to support at least 500 to 1000 simultaneous connections routinely and as many as 10,000 connections if you have many gigabytes of RAM available and the workload from each is low or the response time target undemanding. Increasing the  max_connections  value increases the number of file descriptors that  mysqld  requires. If the required number of descriptors are not available, the server reduces the value of  max_connections . For comments on file descriptor limits, see Section 8.4.3.1, “How MySQL Opens and Closes Tables” . Increasing the  open_files_limit  system variable may be necessary, which may also require raising the operating system limit on how many file descriptors can be used by MySQL. Consult your operating system documentation to determine whether it is possible to increase the limit and how to do so. See also Section B.3.2.16, “File Not Found and Similar Errors” . 5.1.12.2 Administrative Connection Management 984 •The number of file descriptors available. •The desired response time. •The workload from each connection. •The amount of RAM is used for each connection. •The amount of RAM available. •The quality of the thread library on a given platform.