MySQL压力测试/sysbench使用
今天进行了MySQL pxc集群的压测，一般在做项目的时候DBA需要根据业务自定义数据库使用类型，所以在决定阶段，DBA就要根据对业务的预估进行数据库集群的筛选，同时也要对数据库进行压测。
压测的目的是为了测试该机器在哪些条件下数据库压力较大，数据库在该机器的瓶颈大概在哪里。而不是说，我要对比那个数据库性能更好，所谓的性能都是在已经定义好物理机的情况下去找更合适的。所以新的物理机理论上在选择和安装新数据库时都要进行压测。MySQL自带有压测工具，我觉得不好用。所以用的是目前主流的MySQL压测工具 sysbench。
这里还是多说一句，对数据库的选择是根据业务来的，不是说我某个集群性能更好我就要选择他，比如支付系统，不管半同步性能比pxc高多少，都没有PXC的数据强一致性更能保障数据一致，所以这时候不能能因为半同步性能更好而放弃PXC。
当更具业务定义好数据库类型时，就可以安装数据库并进行压测了，主要步骤如下：
1、安装数据库并新建压测用户并授权。
2、安装sysbench，本次我用的时centos7，直接yum安装就行了，官网上有安装命令，比网络上的什么二进制编译、yum编译更加靠谱，所以我也不写啥命令了，去官网看吧
3、写好sysbench执行命令进行压测
sysbench压测工具使用方式：
sysbench不同版本命令不一样，不要拿着网上的别人的命令进行敲打，严谨的方式是 sysbench --help查看当前版本的命令格式，如我使用的版本：
[root@d8555732f478 sysbench]# sysbench testname --help
Usage:
sysbench [options]... [testname] [command]
Commands implemented by most tests: prepare run cleanup help
General options:
--threads=N number of threads to use [1]
--events=N limit for total number of events [0]
--time=N limit for total execution time in seconds [10]
--forced-shutdown=STRING number of seconds to wait after the --time limit before forcing shutdown, or 'off' to disable [off]
--thread-stack-size=SIZE size of stack per thread [64K]
--rate=N average transactions rate. 0 for unlimited rate [0]
--report-interval=N periodically report intermediate statistics with a specified interval in seconds. 0 disables intermediate reports [0]
--report-checkpoints=[LIST,...] dump full statistics and reset all counters at specified points in time. The argument is a list of comma-separated values representing the amount of time in seconds elapsed from start of test when report checkpoint(s) must be performed. Report checkpoints are off by default. []
--debug[=on|off] print more debugging info [off]
--validate[=on|off] perform validation checks where possible [off]
--help[=on|off] print help and exit [off]
--version[=on|off] print version and exit [off]
--config-file=FILENAME File containing command line options
--tx-rate=N deprecated alias for --rate [0]
--max-requests=N deprecated alias for --events [0]
--max-time=N deprecated alias for --time [0]
--num-threads=N deprecated alias for --threads [1]
Pseudo-Random Numbers Generator options:
--rand-type=STRING random numbers distribution {uniform,gaussian,special,pareto} [special]
--rand-spec-iter=N number of iterations used for numbers generation [12]
--rand-spec-pct=N percentage of values to be treated as 'special' (for special distribution) [1]
--rand-spec-res=N percentage of 'special' values to use (for special distribution) [75]
--rand-seed=N seed for random number generator. When 0, the current time is used as a RNG seed. [0]
--rand-pareto-h=N parameter h for pareto distribution [0.2]
Log options:
--verbosity=N verbosity level {5 - debug, 0 - only critical messages} [3]
--percentile=N percentile to calculate in latency statistics (1-100). Use the special value of 0 to disable percentile calculations [95]
--histogram[=on|off] print latency histogram in report [off]
General database options:
--db-driver=STRING specifies database driver to use ('help' to get list of available drivers) [mysql]
--db-ps-mode=STRING prepared statements usage mode {auto, disable} [auto]
--db-debug[=on|off] print database-specific debug information [off]
Compiled-in database drivers:
mysql - MySQL driver
pgsql - PostgreSQL driver
mysql options:
--mysql-host=[LIST,...] MySQL server host [localhost]
--mysql-port=[LIST,...] MySQL server port [3306]
--mysql-socket=[LIST,...] MySQL socket
--mysql-user=STRING MySQL user [sbtest]
--mysql-password=STRING MySQL password []
--mysql-db=STRING MySQL database name [sbtest]
--mysql-ssl[=on|off] use SSL connections, if available in the client library [off]
--mysql-ssl-cipher=STRING use specific cipher for SSL connections []
--mysql-compression[=on|off] use compression, if available in the client library [off]
--mysql-debug[=on|off] trace all client library calls [off]
--mysql-ignore-errors=[LIST,...] list of errors to ignore, or "all" [1213,1020,1205]
--mysql-dry-run[=on|off] Dry run, pretend that all MySQL client API calls are successful without executing them [off]
pgsql options:
--pgsql-host=STRING PostgreSQL server host [localhost]
--pgsql-port=N PostgreSQL server port [5432]
--pgsql-user=STRING PostgreSQL user [sbtest]
--pgsql-password=STRING PostgreSQL password []
--pgsql-db=STRING PostgreSQL database name [sbtest]
Compiled-in tests:
fileio - File I/O test
cpu - CPU performance test
memory - Memory functions speed test
threads - Threads subsystem performance test
mutex - Mutex performance test
See 'sysbench help' for a list of options for each test.
在使用sysbench命令时，需要执行压测方式，该方式是一个脚本文件，如果是yum安装的，大多数在/usr/share/sysbench文件夹下，例：
[root@d8555732f478 sysbench]# ls
bulk_insert.lua oltp_delete.lua oltp_point_select.lua oltp_read_write.lua oltp_update_non_index.lua select_random_points.lua tests
oltp_common.lua oltp_insert.lua oltp_read_only.lua oltp_update_index.lua oltp_write_only.lua select_random_ranges.lua
[root@d8555732f478 sysbench]# pwd
/usr/share/sysbench
看名字也只要这些脚本干嘛的，insert就是压测插入，read压测只读，read_write压测读写，大概是7分读3分写的比例，我们常规使用读写脚本就行了，如果是读写分离的库进行只读或者只写的，可以单独压测读和写
有了启动参数、压测方式脚本、启动命令，那么我们就要开始进行压测了，本次压测命令：
sysbench --mysql-host=45.59.111.111 --mysql-port=33061 --mysql-user=testuser --mysql-password=123456 \
--mysql-db=testdb --report-interval=10 --time=120 --tables=4 --table-size=10000000 --threads=1 \
/usr/share/sysbench/oltp_read_write.lua prepare所以我们常规用到的参数就是：新建的数据库、用户及其密码、报告时间（10秒一次）、执行压测时间（120秒）、压测表数量（4张）、表数据量（1千万）、线程（1）、执行压测方式脚本（读写），最后加上准备命令（prepare）
这里我要说一下 sysbench [options]... [testname] [command] 这里的command，
command命令有三个：prepare、run、cleanup
分别对应的是准备表及其数据、执行压测、清理数据，由于我们在数据库只新建了库没有新建表，所以在参数指定表属性的时候是sysbench自己去新建并且完成指定属性的，所以在压测前我们都要执行prepare命令
等待准备完成后，在执行：
sysbench --mysql-host=45.59.113.211 --mysql-port=33061 --mysql-user=testuser --mysql-password=123456 \
--mysql-db=testdb --report-interval=10 --time=120 --tables=4 --table-size=10000000 --threads=1 \
/usr/share/sysbench/oltp_read_write.lua runrun命令进行压测，这时候就会每隔10秒输出相关压测数据，
最后执行cleanup清除结果：
sysbench --mysql-host=45.59.113.211 --mysql-port=33061 --mysql-user=testuser --mysql-password=123456 \
--mysql-db=testdb --report-interval=10 --time=120 --tables=4 --table-size=10000000 --threads=1 \
/usr/share/sysbench/oltp_read_write.lua cleanup压测方式，默认新建的表大概是4个字段，我们定义了4张表、1000000万数据级，压测这几个属性不变，之后线程从1开始，进行：1、5、10、20、50、100、200、500、1000这几组进行测试，尽量找到性能衰减点。在线程找到衰减点之后，可以试着慢慢调整表数量、表大小等，更换另一个参数需要prepare一次。掌控数据库在该机上的性能瓶颈，对于后期DBA数据库维护有极大的帮助。
比如我这次开了一个线程报告出的结果：
[root@d8555732f478 sysbench]# sysbench --mysql-host=45.59.111.111 --mysql-port=33061 --mysql-user=testuser --mysql-password=123456 \
> --mysql-db=testdb --report-interval=10 --time=120 --tables=4 --table-size=10000000 --threads=1 \
> /usr/share/sysbench/oltp_read_write.lua run
sysbench 1.0.17 (using system LuaJIT 2.0.4)
Running the test with following options:
Number of threads: 1
Report intermediate results every 10 second(s)
Initializing random number generator from current time
Initializing worker threads...
Threads started!
[ 10s ] thds: 1 tps: 12.06 qps: 242.03 (r/w/o: 169.56/23.33/49.14) lat (ms,95%): 147.61 err/s: 0.00 reconn/s: 0.00
[ 20s ] thds: 1 tps: 18.15 qps: 363.61 (r/w/o: 254.74/37.80/71.08) lat (ms,95%): 108.68 err/s: 0.00 reconn/s: 0.00
[ 30s ] thds: 1 tps: 18.09 qps: 361.11 (r/w/o: 252.57/37.18/71.36) lat (ms,95%): 130.13 err/s: 0.00 reconn/s: 0.00
[ 40s ] thds: 1 tps: 23.92 qps: 478.01 (r/w/o: 334.49/47.54/95.98) lat (ms,95%): 90.78 err/s: 0.00 reconn/s: 0.00
[ 50s ] thds: 1 tps: 21.30 qps: 426.56 (r/w/o: 298.77/42.30/85.49) lat (ms,95%): 97.55 err/s: 0.00 reconn/s: 0.00
[ 60s ] thds: 1 tps: 25.00 qps: 499.74 (r/w/o: 349.73/51.10/98.91) lat (ms,95%): 81.48 err/s: 0.00 reconn/s: 0.00
[ 70s ] thds: 1 tps: 23.70 qps: 474.82 (r/w/o: 332.61/45.20/97.00) lat (ms,95%): 87.56 err/s: 0.00 reconn/s: 0.00
[ 80s ] thds: 1 tps: 24.20 qps: 484.30 (r/w/o: 338.80/48.90/96.60) lat (ms,95%): 89.16 err/s: 0.00 reconn/s: 0.00
[ 90s ] thds: 1 tps: 24.30 qps: 484.18 (r/w/o: 338.79/47.70/97.70) lat (ms,95%): 90.78 err/s: 0.00 reconn/s: 0.00
[ 100s ] thds: 1 tps: 25.20 qps: 505.81 (r/w/o: 354.21/49.40/102.20) lat (ms,95%): 84.47 err/s: 0.00 reconn/s: 0.00
[ 110s ] thds: 1 tps: 29.00 qps: 578.40 (r/w/o: 404.70/58.30/115.40) lat (ms,95%): 69.29 err/s: 0.00 reconn/s: 0.00
[ 120s ] thds: 1 tps: 29.70 qps: 594.91 (r/w/o: 416.71/58.10/120.10) lat (ms,95%): 68.05 err/s: 0.00 reconn/s: 0.00
SQL statistics:
queries performed:
read: 38458
write: 5469
other: 11013
total: 54940
transactions: 2747 (22.88 per sec.) --TPS性能
queries: 54940 (457.68 per sec.) --QPS性能
ignored errors: 0 (0.00 per sec.)
reconnects: 0 (0.00 per sec.)
General statistics:
total time: 120.0385s
total number of events: 2747
Latency (ms):
min: 7.22
avg: 43.68
max: 857.01
95th percentile: 94.10
sum: 119989.56
Threads fairness:
events (avg/stddev): 2747.0000/0.00
execution time (avg/stddev): 119.9896/0.00