Table cache hit rate 0%

Hello, I'm new to mysql world and recently installed a new server with these specs: CPU Intel(R) Xeon(R) CPU X3440 @ 2.53GHz 8 GB RAM 500 GB HDD's in Software RAID 1 Centos 6 + Cpanel Hosting around 20 accounts, out of which probably 15 are using mysql The websites don't get a lot of traffic. As an example, last month the server had around 250 GB of traffic usage. I've used Percona's my.cnf tool which worked out ok, apart for some fine tuning which I did with Mysqltuner and Tuning Primer . This is my current my.cnf:


[mysql]

# CLIENT #
port                           = 3306
socket                         = /var/lib/mysql/mysql.sock

[mysqld]

# GENERAL #
#user                           = mysql
default-storage-engine         = InnoDB
socket                         = /var/lib/mysql/mysql.sock
pid-file                       = /var/lib/mysql/server.mygms.net.pid

# MyISAM #
key-buffer-size                = 128M
myisam-recover-options         = FORCE,BACKUP

# SAFETY #
max-allowed-packet             = 16M
max-connect-errors             = 1000000

# DATA STORAGE #
datadir                        = /var/lib/mysql/

# BINARY LOGGING #
log-bin                        = /var/lib/mysql/mysql-bin
expire-logs-days               = 14
sync-binlog                    = 1

# CACHES AND LIMITS #
tmp-table-size                 = 32M
max-heap-table-size            = 32M
query-cache-type               = 0
query-cache-size               = 8M
max-heap-table-size            = 32M
query-cache-type               = 0
query-cache-size               = 8M
query_cache_limit              = 1M
query_cache_type               = 1
max-connections                = 300
thread-cache-size              = 64
open-files-limit               = 65535
table-definition-cache         = 4096
table-open-cache               = 5000
table_cache                    = 64
join_buffer                    = 1M

# INNODB #
#innodb-flush-method            = O_DIRECT
#innodb-log-files-in-group      = 2
#innodb-log-file-size           = 128M
#innodb-flush-log-at-trx-commit = 1
innodb-file-per-table          = 1
innodb-buffer-pool-size        = 2G

# LOGGING #
log-error                      = /var/lib/mysql/server.mygms.net.err
log-queries-not-using-indexes  = 1
slow-query-log                 = 1
slow-query-log-file            = /var/lib/mysql/server-slow.log


 >>  MySQLTuner 1.3.0 - Major Hayden 
 >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
 >>  Run with '--help' for additional options and output filtering
[OK] Currently running supported MySQL version 5.5.35-cll
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MRG_MYISAM 
[--] Data in MyISAM tables: 451M (Tables: 3051)
[--] Data in InnoDB tables: 1G (Tables: 520)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 31

-------- Security Recommendations  -------------------------------------------
[OK] All database users have passwords assigned

-------- Performance Metrics -------------------------------------------------
[--] Up for: 17m 14s (5K q [5.605 qps], 227 conn, TX: 2M, RX: 460K)
[--] Reads / Writes: 92% / 8%
[--] Total buffers: 2.2G global + 3.6M per thread (300 max threads)
[OK] Maximum possible memory usage: 3.2G (42% of installed RAM)
[OK] Slow queries: 4% (248/5K)
[OK] Highest usage of available connections: 1% (4/300)
[OK] Key buffer size / total MyISAM indexes: 128.0M/111.0M
[!!] Key buffer hit rate: 15.5% (90K cached / 76K reads)
[OK] Query cache efficiency: 50.4% (750 cached / 1K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 123 sorts)
[!!] Joins performed without indexes: 13
[OK] Temporary tables created on disk: 13% (164 on disk / 1K total)
[OK] Thread cache hit rate: 98% (4 created / 227 connections)
[!!] Table cache hit rate: 0% (64 open / 157K opened)
[OK] Open file limit used: 0% (21/20K)
[OK] Table locks acquired immediately: 100% (5K immediate / 5K locks)
[OK] InnoDB buffer pool / data size: 2.0G/1.4G
[OK] InnoDB log waits: 0
-------- Recommendations -----------------------------------------------------
General recommendations:
    Run OPTIMIZE TABLE to defragment tables for better performance
    MySQL started within last 24 hours - recommendations may be inaccurate
    Adjust your join queries to always utilize indexes
    Increase table_cache gradually to avoid file descriptor limits
    Read this before increasing table_cache over 64: http://bit.ly/1mi7c4C
Variables to adjust:
    join_buffer_size (> 1.0M, or always use indexes with joins)
    table_cache (> 64)

Does anyone have any idea on how to fix this ? Besides that, should I be looking at anything else? Thank you.

thinkbot

March 09, 2014 06:27

you must run it at least for 24h to get reliable information, your mysql instance run for 17m before mysqltuner

cPanelMichael

March 10, 2014 14:40

Yes, please let MySQL run at least 24 hours before running the tuner to get the most accurate results, as ThinkBot mentioned. Thank you.

and12345

March 12, 2014 10:16

Hi this is the latest result


 >>  MySQLTuner 1.3.0 - Major Hayden 
 >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
 >>  Run with '--help' for additional options and output filtering
[OK] Currently running supported MySQL version 5.5.35-cll
[OK] Operating on 64-bit architecture

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MRG_MYISAM 
[--] Data in MyISAM tables: 475M (Tables: 3051)
[--] Data in InnoDB tables: 1G (Tables: 529)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[!!] Total fragmented tables: 46

-------- Security Recommendations  -------------------------------------------
[OK] All database users have passwords assigned

-------- Performance Metrics -------------------------------------------------
[--] Up for: 3d 17h 9m 5s (5M q [18.404 qps], 81K conn, TX: 5B, RX: 694M)
[--] Reads / Writes: 90% / 10%
[--] Total buffers: 2.2G global + 3.1M per thread (50 max threads)
[OK] Maximum possible memory usage: 2.3G (30% of installed RAM)
[!!] Slow queries: 6% (379K/5M)
[OK] Highest usage of available connections: 46% (23/50)
[OK] Key buffer size / total MyISAM indexes: 128.0M/116.1M
[OK] Key buffer hit rate: 99.5% (126M cached / 688K reads)
[OK] Query cache efficiency: 82.1% (4M cached / 5M selects)
[!!] Query cache prunes per day: 181730
[OK] Sorts requiring temporary tables: 0% (675 temp sorts / 367K sorts)
[!!] Joins performed without indexes: 3102
[OK] Temporary tables created on disk: 14% (29K on disk / 208K total)
[OK] Thread cache hit rate: 99% (23 created / 81K connections)
[!!] Table cache hit rate: 0% (64 open / 7M opened)
[OK] Open file limit used: 0% (121/65K)
[OK] Table locks acquired immediately: 99% (1M immediate / 1M locks)
[OK] InnoDB buffer pool / data size: 2.0G/1.4G
[OK] InnoDB log waits: 0
-------- Recommendations -----------------------------------------------------
General recommendations:
    Run OPTIMIZE TABLE to defragment tables for better performance
    Adjust your join queries to always utilize indexes
    Increase table_cache gradually to avoid file descriptor limits
    Read this before increasing table_cache over 64: http://bit.ly/1mi7c4C
Variables to adjust:
    query_cache_size (> 8M)
    join_buffer_size (> 512.0K, or always use indexes with joins)
    table_cache (> 64)

March 23, 2014 18:53

Can anybody please help me to figure this out :(

March 23, 2014 19:55

remove this table_cache = 64 and you can also increase query_cache_size to 50M and clean double repeated vars like: # CACHES AND LIMITS # tmp-table-size = 32M max-heap-table-size = 32M query-cache-type = 0 query-cache-size = 8M max-heap-table-size = 32M query-cache-type = 0 query-cache-size = 8M query_cache_limit = 1M query_cache_type = 1 to this # CACHES AND LIMITS # tmp-table-size = 32M max-heap-table-size = 32M query-cache-size = 50M query_cache_limit = 1M query_cache_type = 1 and restart mysql table_cache and this table-open-cache = 5000 are the same, table-open-cache is new naming first you set the same value to 5000, then to 64, 5000 gets overwritten so you need to delete table_cache line you got over 3000 MyISAM tables, so 5000 is good number

Table cache hit rate 0%

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