---

测试的过程需要生成测试表，插入测试数据，这个mysqlslap可以自动生成，默认生成一个mysqlslap的schema，如果已经存在则先删除，这里要注意了，不要用–create-schema指定已经存在的库，否则后果可能很严重。可以用
–only-print来打印实际的测试过程：

$mysqlslap -a –only-print
DROP SCHEMA IF EXISTS mysqlslap;
CREATE SCHEMA mysqlslap;
use mysqlslap;
CREATE TABLE g_user (user_id INT(32) ,user_name VARCHAR(128));
INSERT INTO g_user VALUES (1,'liuxiaobin');
…
SELECT user_id,user_name FROM g_user;
INSERT INTO g_user VALUES (2,'liudabin');
DROP SCHEMA IF EXISTS mysqlslap;

可以看到最后由删除一开始创建的schema的动作，整个测试完成后不会在数据库中留下痕迹。假如我们执行一次测试，分别50和100个并发，执行1000次总查询，那么：

$mysqlslap -a –concurrency=50,100 –number-of-queries 1000 –debug-info
Benchmark
Average number of seconds to run all queries: 0.375 seconds
Minimum number of seconds to run all queries: 0.375 seconds
Maximum number of seconds to run all queries: 0.375 seconds
Number of clients running queries: 50
Average number of queries per client: 20

Benchmark
Average number of seconds to run all queries: 0.453 seconds
Minimum number of seconds to run all queries: 0.453 seconds
Maximum number of seconds to run all queries: 0.453 seconds
Number of clients running queries: 100
Average number of queries per client: 10

User time 0.29, System time 0.11
Maximum resident set size 0, Integral resident set size 0
Non-physical pagefaults 4032, Physical pagefaults 0, Swaps 0
Blocks in 0 out 0, Messages in 0 out 0, Signals 0
Voluntary context switches 7319, Involuntary context switches 681

上结果可以看出，50和100个并发分别得到一次测试结果(Benchmark)，并发数越多，执行完所有查询的时间越长。为了准确起见，可以多迭代测试几次:

$ mysqlslap -a –concurrency=50,100 –number-of-queries 1000 –iterations=5 –debug-info
Benchmark
Average number of seconds to run all queries: 0.380 seconds
Minimum number of seconds to run all queries: 0.377 seconds
Maximum number of seconds to run all queries: 0.385 seconds
Number of clients running queries: 50
Average number of queries per client: 20

Benchmark
Average number of seconds to run all queries: 0.447 seconds
Minimum number of seconds to run all queries: 0.444 seconds
Maximum number of seconds to run all queries: 0.451 seconds
Number of clients running queries: 100
Average number of queries per client: 10

User time 1.44, System time 0.67
Maximum resident set size 0, Integral resident set size 0
Non-physical pagefaults 17922, Physical pagefaults 0, Swaps 0
Blocks in 0 out 0, Messages in 0 out 0, Signals 0
Voluntary context switches 36796, Involuntary context switches 4093

测试同时不同的存储引擎的性能进行对比：

$ mysqlslap -a –concurrency=50,100 –number-of-queries 1000 –iterations=5 –engine=myisam,innodb –debug-info
Benchmark
Running for engine myisam
Average number of seconds to run all queries: 0.200 seconds
Minimum number of seconds to run all queries: 0.188 seconds
Maximum number of seconds to run all queries: 0.210 seconds
Number of clients running queries: 50
Average number of queries per client: 20

Benchmark
Running for engine myisam
Average number of seconds to run all queries: 0.238 seconds
Minimum number of seconds to run all queries: 0.228 seconds
Maximum number of seconds to run all queries: 0.251 seconds
Number of clients running queries: 100
Average number of queries per client: 10

Benchmark
Running for engine innodb
Average number of seconds to run all queries: 0.375 seconds
Minimum number of seconds to run all queries: 0.370 seconds
Maximum number of seconds to run all queries: 0.379 seconds
Number of clients running queries: 50
Average num