运行 tuning-primer.sh显示说明
| SLOW QUERIES | 慢查询检查 |
| SLOW QUERIESThe slow query log is enabled. | 说明我已经启用了慢查询记录功能。也就是参数 slow_query_log = 1 |
| Current long_query_time = 5.000000 sec. | 慢查询的阀值时间。也就是参数 long_query_time = 5 |
| You have 17 out of 638844 that take longer than 5.000000 sec. to complete | 说明慢查询日志中记录了17条查询时间超过5秒的语句。 slow_query_log_file=/data/ats_db/mysql-slow.log设置慢查询日志路径。使用
mysqldumpslow命令查询慢日志
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| Your long_query_time seems to be fine | 慢查询阀值时间设置得在推荐的范围内 |
| BINARY UPDATE LOG | 更新二进制日志文件 |
| The binary update log is enabled | 这项说明启用了bin-log日志功能。参数 log-bin = /data/ats_db/mysql-bin |
| Binlog sync is not enabled, you could loose binlog records during a server crash | 没有启用 sync_binlog 选项。也即是将二进制日志实时写入到磁盘通过 sync_binlog=1来指定 |
| WORKER THREADS | 工作线程 |
| Current thread_cache_size = 8 | 当前线程缓存大小。 thread_concurrency = 8 |
| Current threads_cached = 7 | Show status like ‘threads_cached’ |
| Current threads_per_sec = 0 | 脚本先执行Show status like ‘Threads_cached’查看当前的线程创建情况，然后sleep 1后在执行相同的命令，最终后者减去前者的数就是每秒线程创建数。 |
| Historic threads_per_sec = 0 | 该值是使用Threads_cached /uptime获得的。 |
| Your thread_cache_size is fine | |
| MAX CONNECTIONS | 最大连接数 |
| Current max_connections = 1024 | 当前配置文件中设置的并发连接数 |
| Current threads_connected = 2 | 当前线程连接诶数。 show status like ‘Threads_connected’ |
| Historic max_used_connections = 4 | show status like ‘Max_used_connections’; |
| The number of used connections is 0% of the configured maximum. | 这个值使用 Max_used_connections*100/ max_connections得出。 |
| You are using less than 10% of your configured max_connections. Lowering max_connections could help to avoid an over-allocation of memory
See “MEMORY USAGE” section to make sure you are not over-allocating
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Max_used_connections的值不足max_connections值的10%。设置合适的max_connections值有助于节省内存。 |
| MEMORY USAGE | 内存使用 |
| Max Memory Ever Allocated : 841 M | Max Memory Ever Allocated = max_memory |
| Configured Max Per-thread Buffers : 28.40 G | Configured Max Per-thread Buffers = per_thread_buffers |
| Configured Max Global Buffers : 586 M | Configured Max Global Buffers = global_buffers |
| Configured Max Memory Limit : 28.97 G | Configured Max Memory Limit = total_memory 这一项很重要，他是将各个缓存的大小累加，然后同max_connections相乘，从而得出当达到max_connections后需要分配的内存有多少。我这里由于max_connections写得很大，造成了最大内存限制超过了真实内存很多，所以建议不要随意增大max_connections的值。减小 max_connections的值，最终保证最大内存限制在真实内存的90%以下。 |
| Physical Memory : 7.79 G | 实际物理内存 |
| Max memory limit exceeds 90% of physical memory | |
| per_thread_buffers (read_buffer_size+read_rnd_buffer_size +sort_buffer_size+thread_stack+ join_buffer_size+binlog_cache_size)*max_connections per_thread_max_buffers (read_buffer_size+read_rnd_buffer_size +sort_buffer_size+thread_stack +join_buffer_size+binlog_cache_size)*max_used_connections max_used_connections=$(mysql -Bse "show status like 'Max_used_connections'" | awk '{ print $2 }') global_buffers innodb_buffer_pool_size+innodb_additional_mem_pool_size+innodb_log_buffer_size+ key_buffer_size+query_cache_size max_memory= global_buffers+ per_thread_max_buffers total_memory= global_buffers+per_thread_buffers |
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| KEY BUFFER | Key 缓冲 |
| Current MyISAM index space = 222 K | 当前数据库MyISAM表中索引占用磁盘空间 |
| Current key_buffer_size = 512 M | MySQL配置文件中key_buffer_size 设置的大小 |
| Key cache miss rate is 1 : 3316 | Key_read_requests/ Key_reads 这里说明3316次读取请求中有1次丢失(也就是说1次读取磁盘) |
| Key buffer free ratio = 81 % | key_blocks_unused * key_cache_block_size / key_buffer_size * 100 |
| Your key_buffer_size seems to be fine | |
| QUERY CACHE | Query 缓存 |
| Query cache is enabled | 该项说明 我们指定了query_cache_size 的值。如果query_cache_size=0的话这里给出的提示是： Query cache is supported but not enabled Perhaps you should set the query_cache_size |
| Current query_cache_size = 64 M | 当前系统query_cache_size 值大小 [F] |
| Current query_cache_used = 1 M | query_cache_used =query_cache_size-qcache_free_memory |
| Current query_cache_limit = 128 M | 变量 query_cache_limit 大小 |
| Current Query cache Memory fill ratio = 1.79 % | query_cache_used/query_cache_size *100% |
| Current query_cache_min_res_unit = 4 K | show variables like ‘query_cache_min_res_unit’; |
| Your query_cache_size seems to be too high. Perhaps you can use these resources elsewhere |
这项给出的结论是query_cache_size的值设置的有些过高。其比对标准是 “Query cache Memory fill ratio”的值如果小于<25%就会给出这个提示。可以将这些资源应用到其他的地方 |
| MySQL won’t cache query results that are larger than query_cache_limit in size | MySQL不会将大于query_cache_limit的查询结果进行缓存 |
| show status like ‘Qcache%’;Qcache_free_blocks 10 Qcache_free_memory 65891984 Qcache_hits 14437 Qcache_inserts 707 Qcache_lowmem_prunes 0 Qcache_not_cached 216 Qcache_queries_in_cache 540 Qcache_total_blocks 1191 |
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| SORT OPERATIONS | SORT 选项 |
| Current sort_buffer_size = 6 M | show variables like ’sort_buffer%’; |
| Current read_rnd_buffer_size = 16 M | show variables like ‘read_rnd_buffer_size%’; |
| Sort buffer seems to be fine | |
| JOINS | JOINS |
| Current join_buffer_size = 132.00 K | show variables like ‘join_buffer_size%’;join_buffer_size= join_buffer_size+4kb |
| You have had 6 queries where a join could not use an index properly | 这里的6是通过 show status like ‘Select_full_join’; 获得的 |
| 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. |
你需要启用 “log-queries-not-using-indexes” 然后在慢查询日志中看是否有取消索引的joins语句。如果不优化查询语句的话，则需要增大join_buffer_size。 |
| OPEN FILES LIMIT | 文件打开数限制 |
| Current open_files_limit = 1234 files | show variables like ‘open_files_limit%’; |
| The open_files_limit should typically be set to at least 2x-3xthat of table_cache if you have heavy MyISAM usage. | 如果系统中有很多的MyISAM类型的表，则建议将open_files_limit 设置为2X~3X的table_open_cache show status like ‘Open_files’;open_files_ratio= open_files*100/open_files_limit 如果open_files_ratio 超过75% 则需要加大open_files_limit |
| Your open_files_limit value seems to be fine | |
| TABLE CACHE | TABLE 缓存 |
| Current table_open_cache = 512 tables | show variables like ‘table_open_cache’; |
| Current table_definition_cache = 256 tables | show variables like ‘ table_definition_cache ‘; |
| You have a total of 368 tables | SELECTCOUNT(*) FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE=’BASE TABLE’ |
| You have 371 open tables. | show status like ‘Open_tables’; |
| The table_cache value seems to be fine | Open_tables /table_open_cache*100% < 95% |
| You should probably increase your table_definition_cache value. | table_cache_hit_rate =open_tables*100/opened_tables |
| TEMP TABLES | 临时表 |
| Current max_heap_table_size = 16 M | show variables like ‘max_heap_table_size’; |
| Current tmp_table_size = 16 M | show variables like ‘tmp_table_size’; |
| Of 285 temp tables, 11% were created on disk | Created_tmp_tables=285created_tmp_disk_tables*100/ (created_tmp_tables+created_tmp_disk_tables)=11% |
| Created disk tmp tables ratio seems fine | |
| TABLE SCANS | 扫描表 |
| Current read_buffer_size = 6 M | show variables like ‘read_buffer_size’; |
| Current table scan ratio = 9 : 1 | read_rnd_next =show global status like ‘Handler_read_rnd_next’; com_select= show global status like ‘Com_select’; full_table_scans=read_rnd_next/com_select Current table scan ratio = full_table_scans : 1″ 如果表扫描率超过4000，说明进行了太多表扫描，很有可能索引没有建好，增加read_buffer_size值会有一些好处，但最好不要超过8MB。 |
| read_buffer_size seems to be fine | |
| TABLE LOCKING | TABLE LOCKING |
| Current Lock Wait ratio = 0 : 5617 | show global status like’Table_locks_waited’; show global status like
‘Questions’;
如果 Table_locks_waited=0 Current Lock Wait ratio = 0: Questions |
| Your table locking seems to be fine | 本文转自 liang3391 51CTO博客，原文链接:http://blog.51cto.com/liang3391/748795 |
