When evaluating if table_open_cache needs to be adjusted, compare the variable opened_tables with the server uptime variable. Tables should not be increasing very rapidly. If so, increase the table_open_cache value until the opened tables value significantly slows. Consider the number of threads and the number of tables in your database when deciding a cache value.
Multiply maximum concurrent connections (max_connections) by the maximum number of tables per join. Be aware of operating system memory limitations. If table_open_cache is set too high, failed queries and connections are likely.
Try to increase open_files_limit
in case you can't increase table_open_cache variable.