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
  • #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 ;

  #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;

  复制

#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

• 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 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

#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;  

• 开启慢查询
  • 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

  #记录sql执行日志
  SET GLOBAL general_log=1
  SET GLOBAL log_output='FILE';

  复制
  • 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

=============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;

• mysql性能压力测试 mysqlslap

  --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.

  复制

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