mysql常用配置注意项与sql优化
建立数据库：
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- 建立数据库时编码字符集采用utf8
- 排序规则：
- 后缀"_cs"或者"_ci"意思是区分大小写和不区分大小写（Case Sensitive & Case Insensitve）
- 后缀"_bin" 规定每个字符串用二进制编码存储，区分大小写，可以直接存储二进制的内容
- utf-8有默认的排序规则： 命令：SHOW CHARSET LIKE 'utf8%';
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注意点：什么时候需要区分大小写需要在设计和使用时注意
- 如果排序规则使用的是不区分大小写，但部分表字段需要区分大小写，则可以对该字段进行修改：
ALTER TABLE yourTableName MODIFY COLUMN columnName VARCHAR(255) BINARY CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL;
建表：
常见表字段选择请参考其它
表建立完成后，可以插入一定量的，和业务真实基本一致的数据后，通过执行
SELECT * FROM yourTableName PROCEDURE ANALYSE();
根据建议修改表字段定义
注意：此处建议知识针对表中数据，请合理取舍
测试环境 设置：
模拟真实场景数据，放大 xxx 倍，作为上线一段时间后的业务数据预期值
- 统计数据量以配置缓冲区大小
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#统计指定库表的行数和数据量大小 select TABLE_SCHEMA as DB_NAME,TABLE_NAME,TABLE_ROWS,DATA_LENGTH from information_schema.TABLES where table_schema='bdjc_ls' #指定具体的库名 -- AND table_name='t_syxm'; #指定具体表名 ORDER BY DATA_LENGTH DESC
#统计整个mysql数据量大小 select concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as ALL_DB_DATA_SIZE, concat(round(sum(INDEX_LENGTH/1024/1024),2),'MB') as ALL_DB_INDEX_SIZE, concat(round(sum((DATA_LENGTH + INDEX_LENGTH)/1024/1024),2),'MB') as ALL_DB_TOTAL_SIZE from information_schema.TABLES;
#查询全部库或者指定库数据量大小 select table_schema as DB_NAME, concat(round(sum(DATA_LENGTH/1024/1024),2),'MB') as DB_DATA_SIZE, concat(round(sum(INDEX_LENGTH/1024/1024),2),'MB') as DB_INDEX_SIZE, concat(round(sum((DATA_LENGTH + INDEX_LENGTH)/1024/1024),2),'MB') as DB_TOTAL_SIZE from information_schema.TABLES where table_schema='bdjc_ls' #指定具体的库名 AND table_name='t_syxm'; #指定具体表名 group by table_schema order by sum(DATA_LENGTH + INDEX_LENGTH) desc ;
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#主表数据和索引数据的最大内存缓冲区，分配过大，会使Swap占用过多，致使Mysql的查询特慢 SELECT @@innodb_buffer_pool_size;
#windows下可以修改my.ini文件进行设置，默认为8M my.ini文件可以通过 select @@datadir 找到数据根路径， 然后在data上层目录中会发现my.ini
在[mysqld] 下进行修改，包括常见的端口，慢查询等各类参数，注意不要超过最大值
比如我的电脑上文件配置为：# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system. Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.
innodb_buffer_pool_size=3G#linux下通过mysql --help|grep 'my.cnf' 查找配置文件，优先使用考前的， 一般为/etc/my.cnf
设置的innodb_buffer_pool_size 需要为 innodb_buffer_pool_chunk_size*innodb_buffer_pool_instances 的倍数， 如果不是倍数，设置的innodb_buffer_pool_size会自动调整为倍数 innodb_buffer_pool_chunk_size是一个只读值， 当innodb_buffer_pool_size大于1G时，就应该将innodb_buffer_pool_instances值调大#查看设置是否合理
#Performance = innodb_buffer_pool_reads / innodb_buffer_pool_read_requests * 100
show status like 'innodb_buffer_pool_read%';如果Performance百分比很小，则表示够用
参考 https://www.cnblogs.com/wanbin/p/9530833.html
执行 show engine innodb status 查看 Free buffers 大小，如果长时间很大，则可以调小innodb_buffer_pool_size，否则可以适当调大innodb_buffer_pool_size 命中率 = innodb_buffer_pool_read_requests / (innodb_buffer_pool_read_requests + innodb_buffer_pool_reads ) * 100 如果命中率低于99%，则可以考虑增加innodb_buffer_pool_size
- 开启慢查询
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=============开启慢查询======================== vi /etc/my.cnf [mysqld] … slow_query_log = 1 #无效(0或者OFF)、有效(1或者ON) slow_query_log_file = /data/log/mysql/slow_query.log #指定日志文件 long_query_time = 0.5 #超过指定时间的SQL会记录到日志文件(默认时间为10秒，默认单位为秒) #或者全局设置 ----------------- set global slow_query_log = 1; set global slow_query_log_file = '/data/log/mysql/slow_query.log'; set global long_query_time = 0.5;
#记录sql执行日志 SET GLOBAL general_log=1 SET GLOBAL log_output='FILE';
mysqldumpslow 慢日志分析工具 命令： -s 按照那种方式排序 c：访问计数 l：锁定时间 r:返回记录 al：平均锁定时间 ar：平均访问记录数 at：平均查询时间 -t 是top n的意思，返回多少条数据。 -g 可以跟上正则匹配模式，大小写不敏感。 #得到返回记录最多的20个sql mysqldumpslow -s r -t 20 /data/log/mysql/slow_query.log #得到平均访问次数最多的20条sql mysqldumpslow -s ar -t 20 /data/log/mysql/slow_query.log #得到平均访问次数最多,并且里面含有ttt字符的20条sql mysqldumpslow -s ar -t 20 -g "ttt" /data/log/mysql/slow_query.log 如果出现如下错误，Died at /usr/bin/mysqldumpslow line 161, <> chunk 405659.说明要分析的sql日志太大了，请拆分后再分析 拆分的命令为： tail -10000 /data/log/mysql/slow_query.log>/data/log/mysql/slow_query_1_10000.log
- 可以通过explain 解析执行对应的慢查询，通过调整表结构、调整索引、查询语句等常规方式优化查询
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- mysql性能压力测试 mysqlslap
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mysqlslap -h192.168.0.200 -P3306 -uroot -p123456 --number-char-cols=5 --number-int-cols=3 --concurrency=1 --iterations=1 --auto-generate-sql --auto-generate-sql-load-type=mixed --auto-generate-sql-add-autoincrement --engine=innodb,myisam --number-of-queries=1 --auto-generate-sql-write-number=1 --only-print mysqlslap -h192.168.0.200 -P3306 -uroot -p123456 --concurrency=100,500,1000 --iterations=1 --auto-generate-sql --auto-generate-sql-load-type=mixed --auto-generate-sql-add-autoincrement --engine=innodb --number-of-queries=5000 mysqlslap -h192.168.0.200 -P3306 -uroot -p123456 --concurrency=2 --iterations=2 --create-schema=mysql --query="select * from user" --engine=innodb --number-of-queries=20 mysqlslap -h192.168.0.200 -P3306 -uroot -p123456 --concurrency=100 --iterations=1 --create-schema=mysql --query=/root/mysql/query.sql --engine=innodb --number-of-queries=5000
mysqlslap参数一览--print-defaults Print the program argument list and exit. --no-defaults Don't read default options from any option file, except for login file. --defaults-file=# Only read default options from the given file #. --defaults-extra-file=# Read this file after the global files are read. --defaults-group-suffix=# Also read groups with concat(group, suffix) --login-path=# Read this path from the login file. -?, --help Display this help and exit. -a, --auto-generate-sql Generate SQL where not supplied by file or command line. --auto-generate-sql-add-autoincrement Add an AUTO_INCREMENT column to auto-generated tables. --auto-generate-sql-execute-number=# Set this number to generate a set number of queries to run. --auto-generate-sql-guid-primary Add GUID based primary keys to auto-generated tables. --auto-generate-sql-load-type=name Specify test load type: mixed, update, write, key, or read; default is mixed. --auto-generate-sql-secondary-indexes=# Number of secondary indexes to add to auto-generated tables. --auto-generate-sql-unique-query-number=# Number of unique queries to generate for automatic tests. --auto-generate-sql-unique-write-number=# Number of unique queries to generate for auto-generate-sql-write-number. --auto-generate-sql-write-number=# Number of row inserts to perform for each thread (default is 100). --commit=# Commit records every X number of statements. -C, --compress Use compression in server/client protocol. -c, --concurrency=name Number of clients to simulate for query to run. --create=name File or string to use create tables. --create-schema=name Schema to run tests in. --csv[=name] Generate CSV output to named file or to stdout if no file is named. -#, --debug[=#] This is a non-debug version. Catch this and exit. --debug-check This is a non-debug version. Catch this and exit. -T, --debug-info This is a non-debug version. Catch this and exit. --default-auth=name Default authentication client-side plugin to use. -F, --delimiter=name Delimiter to use in SQL statements supplied in file or command line. --detach=# Detach (close and reopen) connections after X number of requests. --enable-cleartext-plugin Enable/disable the clear text authentication plugin. -e, --engine=name Storage engine to use for creating the table. -h, --host=name Connect to host. -i, --iterations=# Number of times to run the tests. --no-drop Do not drop the schema after the test. -x, --number-char-cols=name Number of VARCHAR columns to create in table if specifying --auto-generate-sql. -y, --number-int-cols=name Number of INT columns to create in table if specifying --auto-generate-sql. --number-of-queries=# Limit each client to this number of queries (this is not exact). --only-print Do not connect to the databases, but instead print out what would have been done. -p, --password[=name] Password to use when connecting to server. If password is not given it's asked from the tty. -W, --pipe Use named pipes to connect to server. --plugin-dir=name Directory for client-side plugins. -P, --port=# Port number to use for connection. --post-query=name Query to run or file containing query to execute after tests have completed. --post-system=name system() string to execute after tests have completed. --pre-query=name Query to run or file containing query to execute before running tests. --pre-system=name system() string to execute before running tests. --protocol=name The protocol to use for connection (tcp, socket, pipe, memory). -q, --query=name Query to run or file containing query to run. --secure-auth Refuse client connecting to server if it uses old (pre-4.1.1) protocol. Deprecated. Always TRUE --shared-memory-base-name=name Base name of shared memory. -s, --silent Run program in silent mode - no output. -S, --socket=name The socket file to use for connection. --sql-mode=name Specify sql-mode to run mysqlslap tool. --ssl-mode=name SSL connection mode. --ssl Deprecated. Use --ssl-mode instead. (Defaults to on; use --skip-ssl to disable.) --ssl-verify-server-cert Deprecated. Use --ssl-mode=VERIFY_IDENTITY instead. --ssl-ca=name CA file in PEM format. --ssl-capath=name CA directory. --ssl-cert=name X509 cert in PEM format. --ssl-cipher=name SSL cipher to use. --ssl-key=name X509 key in PEM format. --ssl-crl=name Certificate revocation list. --ssl-crlpath=name Certificate revocation list path. --tls-version=name TLS version to use, permitted values are: TLSv1, TLSv1.1 -u, --user=name User for login if not current user. -v, --verbose More verbose output; you can use this multiple times to get even more verbose output. -V, --version Output version information and exit.
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