Hi there
I've noticed some very weird things happening with my current MySQL setup
on my XP Laptop, a development machine.
For a while, I have been trying to get the MySQL cache to work. Despite
entering the required lines to "my.ini" (the new my.cnf) through notepad
AND MySQL Administrator, the cache does not work.
So, today I took a peek at the 'Health' tab in MySQL Administrator.
Despite no connections to the DB (besides the one through MySQL
Administrator), under the Status Variables tab, then Performance /
Selects, I saw that my select_scan count was increasing by roughly 2 per
second. I shut down MySQL and restarted, and went back to the same tab.
Same thing. When I checked out my query_cache variables, I saw the
"Qcache_not_cached" value also increasing by 2 per second.
Something is querying my database twice a second? With selects???!? Is it
MySQL Administrator? I doubt it, because when I log in to my production
server (hosted elsewhere on linux) with MySQL Administrator and check out
the select_scan value, it is NOT increasing on its own, and the query
cache is working fine.
Can anyone point out some tips to troubleshoot either a) getting my query
cache to work or b) figuring out what is happening with my MySQL
server. It is not increasing CPU load nor RAM usage, so thats a good
thing.
My current "my.ini" file is displayed below (feel free to trim it out!).
Much thanks.
************************************************** **8
# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
#
#
# Installation Instructions
# ----------------------------------------------------------------------
#
# On Linux you can copy this file to /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options
# (@localstatedir@ for this installation) or to
# ~/.my.cnf to set user-specific options.
#
# On Windows you should keep this file in the installation directory
# of your server (e.g. C:\Program Files\MySQL\MySQL Server 4.1). To
# make sure the server reads the config file use the startup option
# "--defaults-file".
#
# To run run the server from the command line, execute this in a
# command line shell, e.g.
# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server 4.1\my.ini"
#
# To install the server as a Windows service manually, execute this in a
# command line shell, e.g.
# mysqld --install MySQL41 --defaults-file="C:\Program Files\MySQL\MySQL
Server 4.1\my.ini"
#
# And then execute this in a command line shell to start the server, e.g.
# net start MySQL41
#
#
# Guildlines for editing this file
# ----------------------------------------------------------------------
#
# In this file, you can use all long options that the program supports.
# If you want to know the options a program supports, start the program
# with the "--help" option.
#
# More detailed information about the individual options can also be
# found in the manual.
#
#
# CLIENT SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.
#
[client]
port=3306
[mysql]
default-character-set=latin1
# SERVER SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this
# file.
#
[mysqld]
# The TCP/IP Port the MySQL Server will listen on
port=3306
#Path to installation directory. All paths are usually resolved relative
to this.
basedir="C:/Program Files/MySQL/MySQL Server 5.0/"
#Path to the database root
datadir="C:/Program Files/MySQL/MySQL Server 5.0/Data/"
# The default character set that will be used when a new schema or table
is
# created and no character set is defined
default-character-set=latin1
# The default storage engine that will be used when create new tables
when
default-storage-engine=INNODB
# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_E NGINE_SUBSTITUTION"
# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.
max_connections=101
# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
query_cache_size = 8M
# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]
table_cache=256
# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
tmp_table_size=7M
# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before. This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
thread_cache_size=8
#*** MyISAM Specific options
# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
myisam_max_sort_file_size=100G
# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method. This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_max_extra_sort_file_size=100G
# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method. This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_sort_buffer_size=12M
# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
key_buffer_size=8M
# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
read_buffer_size=64K
read_rnd_buffer_size=256K
# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.
sort_buffer_size=256K
#*** INNODB Specific options ***
# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.
#skip-innodb
# Additional memory pool that is used by InnoDB to store metadata
# information. If InnoDB requires more memory for this purpose it will
# start to allocate it from the OS. As this is fast enough on most
# recent operating systems, you normally do not need to change this
# value. SHOW INNODB STATUS will display the current amount used.
innodb_additional_mem_pool_size=2M
# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.
innodb_flush_log_at_trx_commit=1
# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).
innodb_log_buffer_size=1M
# 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=10M
# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.
innodb_log_file_size=10M
# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency=8
#Don't cache results that are bigger than this.
query_cache_limit = 1M
#minimal size of unit in wich space for results is allocated (last unit
will be trimed after writing all result data
query_cache_min_res_unit = 4096k
#Query cache type to use.
query_cache_type = 1
#Max packetlength to send/receive from to server.
max_allowed_packet = 4M
#Number of seconds to wait for more data from a connection before
aborting the read
net_read_timeout=45
#Number of seconds to wait for a block to be written to a connection
before aborting the writ
net_write_timeout=60
#The number of seconds the server waits for activity on a connection
before closing it
wait_timeout=28800
************************************************** ***************
