mysql常用配置注意项与sql优化

建立数据库：

• • 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%';

    • 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

  • #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 ;

• #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

  • =============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
• mysql性能压力测试 mysqlslap

  • 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

    --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.

    mysqlslap参数一览