Mysql
MySQL slave 使用所有記憶體，雖然配置為不使用
每隔幾週或幾個月，我的 MySQL 伺服器 (5.6.21) 就會使用整個記憶體，包括交換，儘管它不應該。
伺服器僅用作數據倉庫的備用從屬伺服器。
我們還有其他幾台 MySQL 伺服器，它們都在相同的作業系統上執行相同的版本（使用核心 2.6.32-358.14.1.el6.x86_64 執行的 CentOS 6），但這是唯一顯示此症狀的伺服器。
我無法觀察到特定的查詢。但它發生在早上 05:00 左右的複制期間。數據倉庫更新在 00:00 和 07:00 之間執行。
除了備份之外，此伺服器上也沒有讀取。備份在 21:00 執行，並不是造成這種情況的原因。
到目前為止，只有重新啟動 mysqld 服務才能解決問題。我只是好奇，這是什麼原因造成的。
這是目前的情況：
# free -m total used free shared buffers cached Mem: 48268 47549 718 0 115 872 -/+ buffers/cache: 46562 1706 Swap: 12087 12087 0從
top輸出中可以清楚地看出，只有 MySQL 正在使用所有記憶體：Tasks: 3 total, 0 running, 3 sleeping, 0 stopped, 0 zombie Cpu(s): 0.0%us, 0.0%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 49427328k total, 48695740k used, 731588k free, 119452k buffers Swap: 12378104k total, 12377212k used, 892k free, 894452k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 21387 root 20 0 103m 344 340 S 0.0 0.0 0:00.05 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql/data ... 22234 mysql 20 0 57.9g 44g 4856 S 0.0 94.8 7501:59 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql/data ...伺服器實際上不應該使用超過 36GB 的空間：
@@key_buffer_size / (1024 * 1024): 32.0000 @@query_cache_size / (1024 * 1024): 0.0000 @@innodb_buffer_pool_size / (1024 * 1024): 33792.0000 @@innodb_log_buffer_size / (1024 * 1024): 8.0000 @@max_connections: 10 @@read_buffer_size / (1024 * 1024): 0.1250 @@read_rnd_buffer_size / (1024 * 1024): 0.2500 @@sort_buffer_size / (1024 * 1024): 0.2500 @@join_buffer_size / (1024 * 1024): 0.2500 @@binlog_cache_size / (1024 * 1024): 0.0313 @@thread_stack / (1024 * 1024): 0.2500 @@tmp_table_size / (1024 * 1024): 256.0000 MAX_MEMORY_GB: 35.5504以下是 的重要部分
my.cnf：[mysqld] max-connections = 10 max_connect_errors = 10000 thread_cache_size = 50 key_buffer_size = 32M max_allowed_packet = 128M query_cache_size = 0 query_cache_type = 0 table_open_cache = 2048 open-files-limit = 65535 table-definition-cache = 1024 log_bin = /var/lib/mysql/mysql-bin binlog-format = MIXED sync_binlog = 0 binlog-checksum = CRC32 binlog-rows-query-log_events = 1 expire-logs-days = 1 gtid-mode = on log-slave-updates = true master-info-repository = TABLE master-verify-checksum = 1 sync-master-info = 1 relay-log-info-repository = TABLE innodb_log_group_home_dir = /var/lib/mysql/ innodb-file-format = BARRACUDA innodb-log-files-in-group = 2 innodb_buffer_pool_instances = 4 innodb_log_file_size = 512M innodb_lock_wait_timeout = 43200 innodb_flush_log_at_trx_commit = 1 innodb_flush_method = O_DIRECT innodb_buffer_pool_size = 33G innodb_file_per_table = 1 tmp_table_size = 256M max-heap-table-size = 256M tmpdir = /var/lib/mysql/tmp enforce-gtid-consistency = true的輸出
show engine innodb status：===================================== 2017-03-10 13:37:31 7f2727bdf700 INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 27 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 499196 srv_active, 0 srv_shutdown, 1999252 srv_idle srv_master_thread log flush and writes: 2498448 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 147502997 OS WAIT ARRAY INFO: signal count 268030727 Mutex spin waits 483748333, rounds 5969256182, OS waits 132176123 RW-shared spins 40672399, rounds 210459357, OS waits 2338871 RW-excl spins 112924649, rounds 647917761, OS waits 7715821 Spin rounds per wait: 12.34 mutex, 5.17 RW-shared, 5.74 RW-excl ------------ TRANSACTIONS ------------ Trx id counter 8637239322 Purge done for trx's n:o < 8637239322 undo n:o < 0 state: running but idle History list length 2341 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 0, not started MySQL thread id 611991, OS thread handle 0x7f2727bdf700, query id 12787999 localhost root init show engine innodb status ---TRANSACTION 8637239308, not started MySQL thread id 599812, OS thread handle 0x7f273c0c3700, query id 12781840 Slave has read all relay log; waiting for the slave I/O thread to update it ---TRANSACTION 8637239320, not started MySQL thread id 1, OS thread handle 0x7f30059a8700, query id 0 Waiting for master to send event -------- FILE I/O -------- I/O thread 0 state: waiting for completed aio requests (insert buffer thread) I/O thread 1 state: waiting for completed aio requests (log thread) I/O thread 2 state: waiting for completed aio requests (read thread) I/O thread 3 state: waiting for completed aio requests (read thread) I/O thread 4 state: waiting for completed aio requests (read thread) I/O thread 5 state: waiting for completed aio requests (read thread) I/O thread 6 state: waiting for completed aio requests (write thread) I/O thread 7 state: waiting for completed aio requests (write thread) I/O thread 8 state: waiting for completed aio requests (write thread) I/O thread 9 state: waiting for completed aio requests (write thread) Pending normal aio reads: 0 [0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0] , ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0 Pending flushes (fsync) log: 0; buffer pool: 0 38113420 OS file reads, 692678361 OS file writes, 295468168 OS fsyncs 0.00 reads/s, 0 avg bytes/read, 0.00 writes/s, 0.00 fsyncs/s ------------------------------------- INSERT BUFFER AND ADAPTIVE HASH INDEX ------------------------------------- Ibuf: size 1, free list len 244028, seg size 244030, 1929352 merges merged operations: insert 7499128, delete mark 734782843, delete 66426401 discarded operations: insert 0, delete mark 0, delete 0 Hash table size 73015559, node heap has 35208 buffer(s) 0.00 hash searches/s, 0.00 non-hash searches/s --- LOG --- Log sequence number 130331695761980 Log flushed up to 130331695761980 Pages flushed up to 130331695761980 Last checkpoint at 130331695761980 0 pending log writes, 0 pending chkp writes 279646075 log i/o's done, 0.00 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total memory allocated 36263952384; in additional pool allocated 0 Dictionary memory allocated 1991419 Buffer pool size 2162684 Free buffers 516257 Database pages 1611219 Old database pages 594842 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 21809666, not young 8333442679 0.00 youngs/s, 0.00 non-youngs/s Pages read 37539158, created 237144171, written 399299350 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: 1611219, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---------------------- INDIVIDUAL BUFFER POOL INFO ---------------------- ---BUFFER POOL 0 Buffer pool size 540671 Free buffers 129625 Database pages 402230 Old database pages 148499 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 5461997, not young 2089105440 0.00 youngs/s, 0.00 non-youngs/s Pages read 9402002, created 59409061, written 106858985 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: 402230, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 1 Buffer pool size 540671 Free buffers 128947 Database pages 402917 Old database pages 148753 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 5443941, not young 2080427002 0.00 youngs/s, 0.00 non-youngs/s Pages read 9381960, created 59195515, written 96676260 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: 402917, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 2 Buffer pool size 540671 Free buffers 129695 Database pages 402173 Old database pages 148475 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 5453587, not young 2090513432 0.00 youngs/s, 0.00 non-youngs/s Pages read 9386136, created 59292596, written 96867291 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: 402173, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 3 Buffer pool size 540671 Free buffers 127990 Database pages 403899 Old database pages 149115 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 5450141, not young 2073396805 0.00 youngs/s, 0.00 non-youngs/s Pages read 9369060, created 59246999, written 98896814 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: 403899, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] -------------- ROW OPERATIONS -------------- 0 queries inside InnoDB, 0 queries in queue 0 read views open inside InnoDB Main thread process no. 22234, id 139806582294272, state: sleeping Number of rows inserted 23128153712, updated 2139463431, deleted 353665279, read 10407801812 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================當 xtrabackup 殺死從屬 SQL 執行緒時，我在錯誤日誌中得到的唯一消息是關於每日備份的。
我不知道在哪裡可以查看或在 innodb 監視器輸出中可能有什麼可疑之處。Google搜尋失敗了，因為我得到的只是 MySQL 如何使用記憶體的常見文章。
我很確定您遇到了在 5.6.25 中修復的錯誤 #72885。所以你可以選擇改變：
master-info-repository = FILE; relay-log-info-repository = FILE;或者升級到 5.6.25，發行說明的相關部分指出：
複製：當 master_info_repository=TABLE 時，接收執行緒將接收到的事件資訊儲存在表中。更新表過程中使用的記憶體未正確釋放，這可能導致記憶體不足錯誤。該修復確保在接收器執行緒將事件刷新到中繼日誌文件後，釋放使用的記憶體。（錯誤 #72885、錯誤 #19390463、錯誤 #69848、錯誤 #20124342）