It turns out that installation is performed with a series of settings applied by default, which are not the most optimal for our system in most cases, since there are many more variables (memory, CPU, other services configured, etc.) that we have to consider.
Therefore, it is the best that once the databases have been created, to leave a margin large enough time (for example a couple of days) to make the system stable and to be able to acquire its real work load.
In that moment , we can apply any sort of MySQL optimization or tunning tool, such as MySQL Performance Tuning Primer Script or MySQLTuner.
Then we are going to use the first tool on a Zabbix 1.8.1 installation, utilizing CentOS 5.4 64 bits with a MySQL 5.0.77 database.
[root@centos ~]# ./tuning-primer.sh Using login values from ~/.my.cnf - INITIAL LOGIN ATTEMPT FAILED - Testing for stored webmin passwords: None Found Could not auto detect login info! Found Sockets: /var/lib/mysql/mysql.sock Using: /var/lib/mysql/mysql.sock Would you like to provide a different socket?: [y/N] Do you have your login handy ? [y/N] : y User: root Password: Would you like me to create a ~/.my.cnf file for you? [y/N] : -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.0.77 x86_64 Uptime = 2 days 0 hrs 53 min 41 sec Avg. qps = 19 Total Questions = 3375129 Threads Connected = 15 Server has been running for over 48hrs. It should be safe to follow these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is NOT enabled. Current long_query_time = 10 sec. You have 0 out of 3375150 that take longer than 10 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 http://dev.mysql.com/doc/refman/5.0/en/point-in-time-recovery.html WORKER THREADS Current thread_cache_size = 0 Current threads_cached = 0 Current threads_per_sec = 1 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 100 Current threads_connected = 15 Historic max_used_connections = 21 The number of used connections is 21% of the configured maximum. Your max_connections variable seems to be fine. INNODB STATUS Current InnoDB index space = 112 M Current InnoDB data space = 240 M Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 8 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 : 75 M Configured Max Per-thread Buffers : 274 M Configured Max Global Buffers : 17 M Configured Max Memory Limit : 292 M Physical Memory : 1.96 G Max memory limit seem to be within acceptable norms KEY BUFFER Current MyISAM index space = 71 K Current key_buffer_size = 7 M Key cache miss rate is 1 : 6 Key buffer free ratio = 81 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is supported but not enabled Perhaps you should set the query_cache_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 = 132.00 K You have had 4 queries where a join could not use an index properly 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 = 1024 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_cache value = 64 tables You have a total of 105 tables You have 64 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 TEMP TABLES Current max_heap_table_size = 16 M Current tmp_table_size = 32 M Of 85195 temp tables, 31% were created on disk Effective in-memory tmp_table_size is limited to max_heap_table_size. Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 128 K Current table scan ratio = 0 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 0 : 3375450 Your table locking seems to be fine
When we run the second tool, we pick up the following information:
[root@centos ~]# ./mysqltuner.pl >> MySQLTuner 1.0.1 - Major Hayden <email@example.com> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering Please enter your MySQL administrative login: root Please enter your MySQL administrative password: -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.0.77 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive +BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in InnoDB tables: 240M (Tables: 88) [!!] BDB is enabled but isn't being used [OK] Total fragmented tables: 0 -------- Performance Metrics ------------------------------------------------- [--] Up for: 2d 0h 56m 0s (3M q [19.168 qps], 23K conn, TX: 530M, RX: 331M) [--] Reads / Writes: 69% / 31% [--] Total buffers: 34.0M global + 2.7M per thread (100 max threads) [OK] Maximum possible memory usage: 309.0M (15% of installed RAM) [OK] Slow queries: 0% (0/3M) [OK] Highest usage of available connections: 21% (21/100) [OK] Key buffer size / total MyISAM indexes: 8.0M/67.0K [!!] Key buffer hit rate: 85.3% (239K cached / 35K reads) [!!] Query cache is disabled [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 14K sorts) [!!] Temporary tables created on disk: 31% (38K on disk / 123K total) [!!] Thread cache is disabled [!!] Table cache hit rate: 0% (64 open / 9K opened) [OK] Open file limit used: 0% (0/1K) [OK] Table locks acquired immediately: 100% (3M immediate / 3M locks) [!!] InnoDB data size / buffer pool: 240.7M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Add skip-bdb to MySQL configuration to disable BDB Enable the slow query log to troubleshoot bad queries When making adjustments, make tmp_table_size/max_heap_table_size equal Reduce your SELECT DISTINCT queries without LIMIT clauses Set thread_cache_size to 4 as a starting value Increase table_cache gradually to avoid file descriptor limits Variables to adjust: query_cache_size (>= 8M) tmp_table_size (> 32M) max_heap_table_size (> 16M) thread_cache_size (start at 4) table_cache (> 64) innodb_buffer_pool_size (>= 240M)
In the next two article, we will see how to fit these values.