【发布时间】：2011-12-22 19:39:39
【问题描述】：
我目前正在尝试优化我的数据库。问题如下： 我有一张表，目前存储超过 83Mio。与时间相关的值。它们由高分辨率 (ms) 时间戳索引。我需要做的是计算某个值在给定的时间间隔内出现了多少次 - 例如说我想知道值 1.56787 在时间戳 x 到时间戳 y 的间隔中出现了多少次。现在这几乎需要永远。 我正在使用 InnoDB，我已经花了很多时间优化配置文件，这极大地提高了速度。
感谢您的任何意见，因为我几乎没有办法解决这个问题。我能想到的唯一解决方法是创建包含固定间隔的预计数值的表，这不会真正令人满意，因为整个事情也应该是完全可更新的（我们正在谈论每隔几毫秒到达的新值）。另一个数据库系统会更适合我的问题吗？
这里是解释输出：
Field Type Null Key Default Extra
timestamp bigint(20) NO PRI NULL
ask decimal(6,5) NO NULL
bid decimal(6,5) NO NULL
askvolume decimal(6,5) NO NULL
bidvolume decimal(6,5) NO NULL
# The MySQL server
[mysqld]
port= 3306
socket= "C:/xampp/mysql/mysql.sock"
basedir="C:/xampp/mysql"
tmpdir="C:/xampp/tmp"
datadir="C:/xampp/mysql/data"
pid_file="mysql.pid"
skip-external-locking
key_buffer = 16M
max_allowed_packet = 61M
table_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
log_error="mysql_error.log"
bind-address="192.168.1.2"
# 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!
#
# commented in by lampp security
#skip-networking
skip-federated
# Replication Master Server (default)
# binary logging is required for replication
# log-bin deactivated by default since XAMPP 1.4.11
#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
# Point the following paths to different dedicated disks
#tmpdir = "C:/xampp/tmp"
#log-update = /path-to-dedicated-directory/hostname
# Uncomment the following if you are using BDB tables
#bdb_cache_size = 4M
#bdb_max_lock = 10000
# Comment the following if you are using InnoDB tables
#skip-innodb
innodb_data_home_dir = "C:/xampp/mysql/data"
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = "C:/xampp/mysql/data"
#innodb_log_arch_dir = "C:/xampp/mysql/data"
## You can set .._buffer_pool_size up to 50 - 80 %
## of RAM but beware of setting memory usage too high
innodb_buffer_pool_size = 1024M
innodb_additional_mem_pool_size = 20M
## Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 5M
innodb_log_buffer_size = 16M
innodb_flush_log_at_trx_commit = 0
innodb_lock_wait_timeout = 50
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[isamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
哦，这台机器是具有 6GB RAM 的 i7-950，系统+数据库位于 SSD 上。所以我认为这应该不是问题？
感谢您的帮助，我们将不胜感激！
【问题讨论】：
-
在问题上砸钱不是一种选择吗？您可以做很多事情来提高性能，而更多的钱绝对不是我的首选……但在某些方面，您只需要获得更好的硬件。根据您的描述，您似乎正在接近这一点。话虽如此......我强烈建议给（配置良好的）Postgres 一个机会。
-
没有看到用于运行 MySQl 实例的表和硬件 - 很难提出任何建议。而且我怀疑 Postgres 是否会对 I/O 绑定系统产生任何影响，尤其是知道 InnoDB 的 B-tree 实现是业内最好的实现之一。从长远来看，交换整个 RDBMS 不是一个可行的选择 IMO。我打赌 MySQL 配置不正确（
SHOW VARIABLES LIKE '%innodb%' and output ofEXPLAIN...` 不存在）。如果您可以发布这些内容，则更容易分析问题所在。 -
谢谢大家，我在描述中添加了所有信息......不，如果有必要，投入一些现金应该不是问题，但正如我发布的那样，它是一个带 ssd 和 6GB 的 i7内存...
-
innodb_buffer_pool_size在 6 gig 系统上只有 1 GB。将其增加到 5 个演出。您遇到的另一个问题是将时间戳作为 InnoDB 引擎中的主键。如果您的时间戳不是连续的（下一个比上一个大），那么 InnoDB 会对记录进行物理重新排序，这会在插入时由于聚集的主键而降低其性能。在您的 select 语句之前添加EXPLAIN关键字，以查看 MySQL 想要检查的行数并发布输出。
标签： mysql optimization