所有网站挂起，直到完成对同一用户的请求[重复]

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Am using HTML and PHP for my internal web Reporting. The problem is, when an user using report-x and request data and try to open other (report-y) at the same time the report-x is running the query, report-y is hang until report-x is finish, and then report-y respond.

I am using PDO to connect to my DataBase, i use session_start(); but it still hang.

I expect the user can use a second report while the first report is working.

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