MySQL似乎希望在对其执行任何大型插入或select语句之后将整个表保留在缓存中（表大小= ~20GB）。现在我的innodb缓冲池是20GB。总RAM为32GB。我将提供innodb状态的一些内存使用和输出以及mysqltuner的输出。这几天让我疯了。请帮忙！我感谢您的任何反馈，如果您需要更多信息，请与我们联系。
此外，执行'FLUSH TABLES'只需关闭并在内存中重新打开它们。至少我认为这是正在发生的事情。这是我执行一堆插入之前的innodb当前内存状态：
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 21978152960; in additional pool allocated 0
Dictionary memory allocated 6006471
Buffer pool size 1310719
Free buffers 347984
Database pages 936740
Old database pages 345808
Modified db pages 0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 78031, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 551887, created 384853, written 4733512
0.00 reads/s, 0.00 creates/s, 0.00 writes/s
No buffer pool page gets since the last printout
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 936740, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
mysqld百分比内存使用量： 60.9％
插入后mysqld百分比内存使用量（1百万记录）： 63.3％
然后经过更多插入（3密耳记录）： 70.2％
不应该大约 62.5％？ （20 / 32GB）总公羊？
输出顶部排序我的MEM使用情况：
top - 14:30:56 up 23:25, 3 users, load average: 3.63, 2.31, 1.91
Tasks: 208 total, 4 running, 204 sleeping, 0 stopped, 0 zombie
Cpu(s): 96.0%us, 3.0%sy, 0.0%ni, 0.0%id, 1.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 28821396k total, 28609868k used, 211528k free, 138696k buffers
Swap: 33554428k total, 30256k used, 33524172k free, 1208184k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1228 mysql 20 0 25.1g 19g 5512 S 31 70.2 62:01.10 mysqld
这是执行这些插入后的innodb内存输出：
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 21978152960; in additional pool allocated 0
Dictionary memory allocated 6006471
Buffer pool size 1310719
Free buffers 271419
Database pages 1011886
Old database pages 373510
Modified db pages 4262
Pending reads 1
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 82521, not young 0
7.08 youngs/s, 0.00 non-youngs/s
Pages read 585218, created 426667, written 5192189
24.08 reads/s, 53.08 creates/s, 1135.07 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 1011886, unzip_LRU len: 0
I/O sum[0]:cur[266], unzip sum[0]:cur[0]
根据innodb状态，分配的总内存是相同的 - 但我的操作系统（虚拟Ubuntu服务器12.04）报告的内存使用量更多。内存使用保持不变，在这里我将其定义为MySQL服务而不是“释放”内存。有什么建议吗？
来自mysqltuner.pl的输出：
-------- Storage Engine Statistics -------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MRG_MYISAM
[--] Data in MyISAM tables: 226M (Tables: 287)
[--] Data in InnoDB tables: 33G (Tables: 1000)
[--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17)
[--] Data in MEMORY tables: 0B (Tables: 1)
[!!] Total fragmented tables: 959
-------- Security Recommendations -------------------------------------------
[OK] All database users have passwords assigned
-------- Performance Metrics -------------------------------------------------
[--] Up for: 23h 14m 27s (1M q [14.603 qps], 6K conn, TX: 16B, RX: 1B)
[--] Reads / Writes: 46% / 54%
[--] Total buffers: 22.2G global + 2.7M per thread (151 max threads)
[OK] Maximum possible memory usage: 22.6G (82% of installed RAM)
[OK] Slow queries: 0% (6/1M)
[OK] Highest usage of available connections: 6% (10/151)
[OK] Key buffer size / total MyISAM indexes: 2.0G/58.7M
[OK] Key buffer hit rate: 100.0% (216M cached / 38K reads)
[OK] Query cache efficiency: 81.2% (799K cached / 984K selects)
[!!] Query cache prunes per day: 5561
[OK] Sorts requiring temporary tables: 4% (819 temp sorts / 16K sorts)
[!!] Temporary tables created on disk: 27% (6K on disk / 22K total)
[OK] Thread cache hit rate: 99% (11 created / 6K connections)
[!!] Table cache hit rate: 0% (97 open / 10K opened)
[OK] Open file limit used: 12% (129/1K)
[OK] Table locks acquired immediately: 99% (433K immediate / 433K locks)
[!!] InnoDB buffer pool / data size: 20.0G/33.6G
[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
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
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 (> 128M)
tmp_table_size (> 128M)
max_heap_table_size (> 16M)
table_cache (> 431)
innodb_buffer_pool_size (>= 33G)
答案 0 :(得分：1)
InnoDB状态不报告使用malloc（）从系统分配的额外内存。
缓冲池大小不包括~10％的额外内存，用于存储有关缓冲池中页面的元数据，如清理和修改页面的列表。
缓冲池还存储更改缓冲区的页面，这基本上是对尚未合并的非唯一索引的更新。这不会增加缓冲池的大小，更像是暂时从缓冲池中窃取一些空间。我只是提到它，因为你的缓冲池可能需要比你的数据/索引页面大一点。
InnoDB中还有其他RAM用途，比如锁结构和以前打开过的所有表的内存数据字典。
很难准确了解MySQL的内存使用情况。