Mysql takes up heavy load on CPU and eats most of the ram

Mar 29, 2014
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Hi,
I'm running a dedicated server with Xeon 8 cores and 16 GB RAM...
I was trying to update mysql optimization settings for my.cnf as per recommendation by mysqltuner.pl. But still mysql utilizes heavy load of CPU and Heavy RAM.

How to apply recommendation by mysqltuner.pl---
------------------
Run OPTIMIZE TABLE to defragment tables for better performance
Adjust your join queries to always utilize indexes---> how to apply this settings.

my.cnf settings---

Code:
[mysqld]
    local-infile=0

    connect_timeout=360
    wait_timeout=2400
    interactive_timeout=2400
    default-storage-engine=MyISAM

    max_connections = 400
    max_user_connections = 100

    key_buffer_size=1400M
    join_buffer_size=4M
    sort_buffer_size=512K
    read_rnd_buffer_size=512K

    slow_query_log=1
    slow_query_log_file=mysql-slow.log
    long_query_time=0.1

    query_cache_type = 1
    query_cache_size = 150M
    query_cache_limit = 1M

    max_allowed_packet=32M
    tmp_table_size=256M
    max_heap_table_size=256M
    open_files_limit=100000

    table_definition_cache=2000
    table_open_cache=6000

    thread_cache_size=64

    innodb_buffer_pool_size=662M
    innodb_file_per_table=1
Please suggest the best possible settings for the said above..
Thanking you,
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
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Hello :)

Could you post the full output of the MySQL tuner results so we can get a better idea of your existing performance statistics?

Thank you.
 
Mar 29, 2014
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Root Administrator
Hi,
After that from forum I got to know mysqltuner does not support mysql 5.5 any more...
I'm using tuning-primer.sh which says the following-
Code:
bash  tuning-primer.sh

        -- MYSQL PERFORMANCE TUNING PRIMER --
             - By: Matthew Montgomery -

MySQL Version 5.5.36-cll x86_64

Uptime = 0 days 21 hrs 33 min 51 sec
Avg. qps = 84
Total Questions = 6550459
Threads Connected = 35

Warning: Server has not been running for at least 48hrs.
It may not be safe to use these recommendations

To find out more information on how each of these
runtime variables effects performance visit:
[url=http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html]MySQL :: MySQL 5.5 Reference Manual :: 5.1.4 Server System Variables[/url]
Visit [url]http://www.mysql.com/products/enterprise/advisors.html[/url]
for info about MySQL's Enterprise Monitoring and Advisory Service

SLOW QUERIES
The slow query log is enabled.
Current long_query_time = 10.000000 sec.
You have 40963 out of 6550815 that take longer than 10.000000 sec. to complete
Your long_query_time seems to be fine

BINARY UPDATE LOG
The binary update log is NOT enabled.
You will not be able to do point in time recovery
See [url=http://dev.mysql.com/doc/refman/5.5/en/point-in-time-recovery.html]MySQL :: MySQL 5.5 Reference Manual :: 7.5 Point-in-Time (Incremental) Recovery Using the Binary Log[/url]

WORKER THREADS
Current thread_cache_size = 6
Current threads_cached = 0
Current threads_per_sec = 0
Historic threads_per_sec = 0
Your thread_cache_size is fine

MAX CONNECTIONS
Current max_connections = 150
Current threads_connected = 37
Historic max_used_connections = 102
The number of used connections is 68% of the configured maximum.
Your max_connections variable seems to be fine.

INNODB STATUS
Current InnoDB index space = 266 M
Current InnoDB data space = 768 M
Current InnoDB buffer pool free = 0 %
Current innodb_buffer_pool_size = 64 M
Depending on how much space your innodb indexes take up it may be safe
to increase this value to up to 2 / 3 of total system memory

MEMORY USAGE
Max Memory Ever Allocated : 661 M
Configured Max Per-thread Buffers : 675 M
Configured Max Global Buffers : 202 M
Configured Max Memory Limit : 877 M
Physical Memory : 15.57 G
Max memory limit seem to be within acceptable norms

KEY BUFFER
Current MyISAM index space = 3.14 G
Current key_buffer_size = 96 M
Key cache miss rate is 1 : 167
Key buffer free ratio = 66 %
Your key_buffer_size seems to be fine

QUERY CACHE
Query cache is enabled
Current query_cache_size = 32 M
Current query_cache_used = 19 M
Current query_cache_limit = 2 M
Current Query cache Memory fill ratio = 60.88 %
Current query_cache_min_res_unit = 4 K
MySQL won't cache query results that are larger than query_cache_limit in size

SORT OPERATIONS
Current sort_buffer_size = 2 M
Current read_rnd_buffer_size = 256 K
Sort buffer seems to be fine

JOINS
Current join_buffer_size = 1.00 M
You have had 4910 queries where a join could not use an index properly
You have had 1 joins without keys that check for key usage after each row
You should enable "log-queries-not-using-indexes"
Then look for non indexed joins in the slow query log.
If you are unable to optimize your queries you may want to increase your
join_buffer_size to accommodate larger joins in one pass.

Note! This script will still suggest raising the join_buffer_size when
ANY joins not using indexes are found.

OPEN FILES LIMIT
Current open_files_limit = 8192 files
The open_files_limit should typically be set to at least 2x-3x
that of table_cache if you have heavy MyISAM usage.
Your open_files_limit value seems to be fine

TABLE CACHE
Current table_open_cache = 1024 tables
Current table_definition_cache = 800 tables
You have a total of 14234 tables
You have 1024 open tables.
Current table_cache hit rate is 0%
, while 100% of your table cache is in use
You should probably increase your table_cache
You should probably increase your table_definition_cache value.

TEMP TABLES
Current max_heap_table_size = 32 M
Current tmp_table_size = 32 M
Of 263175 temp tables, 24% were created on disk
Created disk tmp tables ratio seems fine

TABLE SCANS
Current read_buffer_size = 1 M
Current table scan ratio = 659 : 1
read_buffer_size seems to be fine

TABLE LOCKING
Current Lock Wait ratio = 1 : 150
You may benefit from selective use of InnoDB.
If you have long running SELECT's against MyISAM tables and perform
frequent updates consider setting 'low_priority_updates=1'
If you have a high concurrency of inserts on Dynamic row-length tables
consider setting 'concurrent_insert=ALWAYS'.
One time I increased the value of table cache and set slow query log. After that I optimize tables...that's it.

Please update asap, since server becomes unstable.
I'm using centos 6.4, Xeon 8 cores with 16 GB ram.

Even, I tried default mysql values but it did not work...

Waiting for your revert,
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,909
2,227
463
Please update asap, since server becomes unstable.
Most advice for MySQL tuning will come from other users. It's not officially supported by cPanel. You mentioned that MySQL is unstable. Is it failing? If so, what do you see in your MySQL error log when MySQL fails?

Thank you.
 
Mar 29, 2014
5
0
1
cPanel Access Level
Root Administrator
Hi,
I have seen mysql cpu usage goes 100% sometimes 200% and even 500%. I'm totally helpless to manage it.
Although I have been adjusting the settings... But no use.

Can you suggest the best?
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,909
2,227
463
Try running the following command when you notice heavy MySQL usage:

Code:
mysqladmin processlist
Look for excessive usage from specific databases.

Thank you.