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To measure the speed of a specific MySQL expression or function, invoke theBENCHMARK() function using themysql client program. Its syntax isBENCHMARK(loop_count,expr). The return value is always zero, butmysql prints a line displaying approximately how long the statement took to execute. For example:

mysql> SELECT BENCHMARK(1000000,1+1);+------------------------+| BENCHMARK(1000000,1+1) |+------------------------+|                      0 |+------------------------+1 row in set (0.32 sec)

This result was obtained on a Pentium II 400MHz system. It shows that MySQL can execute 1,000,000 simple addition expressions in 0.32 seconds on that system.

The built-in MySQL functions are typically highly optimized, but there may be some exceptions.BENCHMARK() is an excellent tool for finding out if some function is a problem for your queries.