MISAM 的性能问题

Question

伙计们

我需要从表 A（大约 6000 万条记录和 myisam 存储引擎）生成报告。表 A 每 15 分钟转储一次 cdr 文件。

我想根据 (date to) 和 (date from) 生成报告

我尝试过的几个场景如下

1) 我试图创建一个临时表 B（使用 create table B Engine=Myisam select a,c,d from table A）

在 processlist 中，如果表 A 正在与 cdr 记录一起转储，则表 A 被锁定。并将保持锁定状态。

如果表 A 中没有插入 cdr 记录，则大约 1 分钟后会创建临时表 B。

当文件被转储到表 A 中时，我有什么方法可以创建临时表 B。

2）我试图创建一个临时表 B（使用 create table B 从表 A 中选择 a.c.d）

在这种情况下，创建 INNODB 引擎的表 b 将占用大量空间

3) 如果我创建临时 b 引擎 = 内存，只需要信息，它是否有任何性能问题。

我附上my.cnf如下

# Example MySQL config file for very large systems.
#
# This is for a large system with memory of 1G-2G where the system runs mainly
# MySQL.
#
# MySQL programs look for option files in a set of
# locations which depend on the deployment platform.
# You can copy this option file to one of those
# locations. For information about these locations, see:
# http://dev.mysql.com/doc/mysql/en/option-files.html
#
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.

# The following options will be passed to all MySQL clients
[client]
#password   = your_password
port        = 3306
socket      = /var/lib/mysql/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port        = 3306
socket      = /var/lib/mysql/mysql.sock
skip-locking
key_buffer_size = 3G
max_allowed_packet = 16M
table_open_cache = 1024
sort_buffer_size = 256M
read_buffer_size = 1024M
read_rnd_buffer_size = 64M
myisam_sort_buffer_size = 4G
thread_cache_size = 8
query_cache_size = 256M
query_cache_limit = 256M

max_connections = 100   
max_heap_table_size = 64M
join_buffer_size = 8M
tmp_table_size = 1024M
myisam_max_sort_file_size = 3G
slow_query_log



# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!
#
#skip-networking

# Replication Master Server (default)
# binary logging is required for replication
log-bin=mysql-bin

# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
server-id   = 1

# Replication Slave (comment out master section to use this)
#
# To configure this host as a replication slave, you can choose between
# two methods :
#
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#
#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,
#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#
#    where you replace <host>, <user>, <password> by quoted strings and
#    <port> by the master's port number (3306 by default).
#
#    Example:
#
#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
#
# OR
#
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a master.info file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the master.info file, unless you shutdown
#    the slave server, delete master.info and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
#
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id       = 2
#
# The replication master for this slave - required
#master-host     =   <hostname>
#
# The username the slave will use for authentication when connecting
# to the master - required
#master-user     =   <username>
#
# The password the slave will authenticate with when connecting to
# the master - required
#master-password =   <password>
#
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  <port>
#
# binary logging - not required for slaves, but recommended
#log-bin=mysql-bin
#
# binary logging format - mixed recommended
#binlog_format=mixed

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/lib/mysql
#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 384M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 100M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 100M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates

[myisamchk]
key_buffer_size = 3G
sort_buffer_size = 512M
read_buffer = 1024M
write_buffer = 8M

[mysqlhotcopy]
interactive-timeout

发散

Answer 1

试试这个（在一个 MySQL 会话中）：

SET TRANSACTION ISOLATION LEVEL
READ UNCOMMITTED;

<place here the blocking query>

您应该看到 SQL 没有阻止 INSERT