max_prepared_stmt_count 参数限制了同一时间在mysqld上所有session中prepared 语句的上限。
它的取值范围为“0 – 1048576”，默认为16382。
mysql对于超出max_prepared_stmt_count的prepare语句就会报Can’t create more than max_prepared_stmt_count statements (current value: 16382)”错误
FATAL: MySQL error: 1461 “Can’t create more than max_prepared_stmt_count statements (current value: 16382)”
set global max_prepared_stmt_count=100000;