優化MySQL數據庫的快速計數

Question

我目前正在試圖優化我的數據庫。問題是以下幾點： 我有一張表，當前存儲超過83Mio。時間依賴值。它們由高分辨率（ms）時間戳索引。我需要做的是計算特定值出現在給定時間間隔內的次數 - 例如說，我想知道值1.56787在時間戳x到時間戳y的時間間隔中出現了多少次。現在這需要幾乎永遠。 即時通訊使用InnoDB，我已經花了很多時間來優化配置文件，這增加了速度immensly。

我很感激任何輸入，因爲我幾乎不知道如何將它關閉。我能想到的唯一解決方法是創建包含固定時間間隔的預計數值的表，由於整個事物也應該是完全可更新的（我們正在討論每隔幾毫秒到達的新值），所以這並不令人滿意。另一個數據庫系統會更適合我的問題嗎？

下面是解釋輸出：

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 

喔機器是i7-950的RAM 6GB和系統+數據庫上的SSD。所以我認爲這不應該是問題？

感謝您的幫助，我們將非常感謝！

Answer 1

第一步：如果您尚未完成此操作，請使用explain plan查看查詢的瓶頸究竟是什麼，以及引擎是否正確使用索引。

第二步：按時間戳範圍對錶進行分區。我不確定MySQL/InnoDB是否具備這種能力，但如果沒有，您最好更換DBMS。

在任何情況下，MySQL都不是高性能的好選擇：根據您的需求，使用Oracle或Postgre或者甚至內存存儲可能會更好（尤其是如果您不太在意的話）爲了安全而不是表現）。

Answer 2

我沒有感覺你在你的索引時間戳值的值範圍，但在我看來，partitioning你的表可以幫助你在這裏。具體爲RANGE partitioning或HASH partitioning。

這應該會顯着提升性能。

Answer 3

如果時間範圍可以表示爲一系列範圍（月，日，星期等），則可以引入類似日期前綴列的內容，這將顯着減少使用IN()表達式的檢查行數。

這是一個公開的想法的文章：http://www.mysqlperformanceblog.com/2010/01/09/getting-around-optimizer-limitations-with-an-in-list/