A fix for Bug#5787 "mysql_stmt_prepare is upto 8 times slower":
it's crucial to disable Nagle algorithm on client for no-reply commands (like mysql_stmt_free) to always work fast. Nagle algorithm instructs the sender to buffer (store) data if any unacknowledged data is outstanding and the size of to-send data is less than the network segment. It was exactly the case with COM_STMT_CLOSE after COM_STMT_PREPARE, so the client was waiting for Nagle timer to expire or for ACK from the server, while the server was holding up ACK because of delayed acknowledgement algorithm. The tricky part is that we have been already disabling Nagle algorithm (by setting TCP_NODELAY) almost everywhere except Windows (and maybe Netware). It is the reason why the bug was repeatable only with Windows client. vio/viosocket.c: A fix for Bug#5787 "mysql_stmt_prepare is upto 8 times slower": if we disable Nagle algorithm, do it everywhere.
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