Mysql
InnoDB 偶爾簡單的查詢很慢，因為查詢結束很慢
我們的其中一台生產伺服器存在嚴重問題。有問題的設置是具有 16 GB 記憶體和 250GB SSD 的 CentOS 7 64 位伺服器（因此設置應該非常快）。LEMP 堆棧配置了 MariaDB 10.1.29。我們在這台伺服器上執行了大約 20 個應用程序，每個應用程序都使用自己的數據庫。
幾週前，我們在狀態監視器中看到（以 5 分鐘間隔 ping 每個應用程序並測量響應時間），3 個應用程序不時執行非常緩慢。（響應時間從 2 秒到 10 秒，而平均值約為 0.1 秒）。MariaDB 的慢日誌充滿了慢查詢（其中大多數是用於會話儲存的簡單插入、選擇和更新查詢），有時需要長達 15 秒，但僅來自這三個應用程序。
這三個應用程序與其他應用程序相比有什麼共同點，它們都使用
InnoDB而不是MyISAM. 因此，為了進一步調試，我們將另外 3 個應用程序從 MyISAM 轉換為 InnoDB，這些應用程序也開始遭受同樣的延遲。我能夠捕捉到慢查詢的配置文件，問題似乎與
query end.
問題是（或者是什麼使調試變得困難），我們看不到任何規律性，並且在 99% 的情況下查詢都執行得很快。
編輯以添加更多指標和統計數據，也在評論中，但提供更好的概述
範例：PROFILE 簡單 UPDATE 查詢列表：
213 | 0.01676252 | update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1 214 | 0.00950012 | update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1 215 | 0.00679076 | update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1 216 | 4.06162153 | update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1 217 | 0.20616296 | update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1216的解釋：
# Time: 171211 11:32:59 # User@Host: msze[msze] @ localhost [] # Thread_id: 17956 Schema: msze QC_hit: No # Query_time: 4.061399 Lock_time: 0.000129 Rows_sent: 0 Rows_examined: 1 # Rows_affected: 0 # # explain: id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra # explain: 1 SIMPLE users range PRIMARY PRIMARY 4 NULL 1 1.00 100.00 100.00 Using where #顯示 216 的個人資料：
MariaDB [msze]> SHOW PROFILE FOR QUERY 216; +----------------------+----------+ | Status | Duration | +----------------------+----------+ | starting | 0.000086 | | checking permissions | 0.000010 | | Opening tables | 0.000027 | | After opening tables | 0.000013 | | System lock | 0.000006 | | Table lock | 0.000006 | | init | 0.000071 | | updating | 0.000099 | | end | 0.000008 | | query end | 4.061019 | | closing tables | 0.000032 | | Unlocking tables | 0.000022 | | freeing items | 0.000012 | | updating status | 0.000028 | | logging slow query | 0.000155 | | cleaning up | 0.000026 | +----------------------+----------+
SHOW ENGINE INNODB STATUS在慢查詢之一之後：| InnoDB | | ===================================== 2017-12-13 00:13:40 7f4284d09700 INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 23 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 3715 srv_active, 0 srv_shutdown, 284907 srv_idle srv_master_thread log flush and writes: 288609 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 3356 OS WAIT ARRAY INFO: signal count 3336 Mutex spin waits 7065, rounds 46684, OS waits 1287 RW-shared spins 1838, rounds 55280, OS waits 1837 RW-excl spins 35, rounds 6925, OS waits 219 Spin rounds per wait: 6.61 mutex, 30.08 RW-shared, 197.86 RW-excl ------------ TRANSACTIONS ------------ Trx id counter 17909160 Purge done for trx's n:o < 17909160 undo n:o < 0 state: running but idle History list length 16 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 0, not started MySQL thread id 35655, OS thread handle 0x7f4284d09700, query id 1503058 localhost msze init SHOW ENGINE INNODB STATUS ---TRANSACTION 17909158, not started flushing log, thread declared inside InnoDB 4999 mysql tables in use 1, locked 1 MySQL thread id 35641, OS thread handle 0x7f4284ccc700, query id 1503057 localhost msze query end update `users` set `remember_token` = 'PpIxVPJE4Hkc981B6C6dT0aeCaExgjmR2GOydFqDZpU36O6z0mOsGic1DYIO' where `id` = 1 ---TRANSACTION 17851651, not started MySQL thread id 1, OS thread handle 0x7f428971d700, query id 0 Waiting for requests -------- 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 (read thread) I/O thread 7 state: waiting for completed aio requests (read thread) I/O thread 8 state: waiting for completed aio requests (read thread) I/O thread 9 state: waiting for completed aio requests (read thread) I/O thread 10 state: waiting for completed aio requests (write thread) I/O thread 11 state: waiting for completed aio requests (write thread) I/O thread 12 state: waiting for completed aio requests (write thread) I/O thread 13 state: waiting for completed aio requests (write thread) I/O thread 14 state: waiting for completed aio requests (write thread) I/O thread 15 state: waiting for completed aio requests (write thread) I/O thread 16 state: waiting for completed aio requests (write thread) I/O thread 17 state: waiting for completed aio requests (write thread) Pending normal aio reads: 0 [0, 0, 0, 0, 0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0, 0, 0, 0, 0] , ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0 Pending flushes (fsync) log: 1; buffer pool: 0 9331 OS file reads, 32092 OS file writes, 12460 OS fsyncs 0.00 reads/s, 0 avg bytes/read, 1.65 writes/s, 1.52 fsyncs/s ------------------------------------- INSERT BUFFER AND ADAPTIVE HASH INDEX ------------------------------------- Ibuf: size 1, free list len 0, seg size 2, 17 merges merged operations: insert 13, delete mark 6, delete 0 discarded operations: insert 0, delete mark 0, delete 0 60.00 hash searches/s, 6.48 non-hash searches/s --- LOG --- Log sequence number 885763031 Log flushed up to 885762812 Pages flushed up to 885752827 Last checkpoint at 885752827 Max checkpoint age 650641675 Checkpoint age target 630309123 Modified age 10204 Checkpoint age 10204 1 pending log writes, 0 pending chkp writes 7104 log i/o's done, 1.43 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total memory allocated 2249195520; in additional pool allocated 0 Total memory allocated by read views 232 Internal hash tables (constant factor + variable factor) Adaptive hash index 36929728 (35401816 + 1527912) Page hash 1107208 (buffer pool 0 only) Dictionary cache 21776008 (8851984 + 12924024) File system 1924912 (812272 + 1112640) Lock system 5314496 (5313416 + 1080) Recovery system 0 (0 + 0) Dictionary memory allocated 12924024 Buffer pool size 131070 Buffer pool size, bytes 2147450880 Free buffers 122651 Database pages 8326 Old database pages 3102 Modified db pages 135 Percent of dirty pages(LRU & free pages): 0.103 Max dirty pages percent: 90.000 Pending reads 0 Pending writes: LRU 0, flush list 3, single page 0 Pages made young 1, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 8093, created 233, written 23247 0.00 reads/s, 0.00 creates/s, 0.17 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: 8326, 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 65535 Buffer pool size, bytes 1073725440 Free buffers 61371 Database pages 4115 Old database pages 1528 Modified db pages 61 Percent of dirty pages(LRU & free pages): 0.093 Max dirty pages percent: 90.000 Pending reads 0 Pending writes: LRU 0, flush list 3, single page 0 Pages made young 0, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3996, created 119, written 11904 0.00 reads/s, 0.00 creates/s, 0.09 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: 4115, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 1 Buffer pool size 65535 Buffer pool size, bytes 1073725440 Free buffers 61280 Database pages 4211 Old database pages 1574 Modified db pages 74 Percent of dirty pages(LRU & free pages): 0.113 Max dirty pages percent: 90.000 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 1, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 4097, created 114, written 11343 0.00 reads/s, 0.00 creates/s, 0.09 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: 4211, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] -------------- ROW OPERATIONS -------------- 1 queries inside InnoDB, 0 queries in queue 0 read views open inside InnoDB 0 RW transactions active inside InnoDB 0 RO transactions active inside InnoDB 0 out of 1000 descriptors used Main thread process no. 26161, id 139920697968384, state: sleeping Number of rows inserted 1949, updated 2279, deleted 1540, read 53481986 0.00 inserts/s, 1.39 updates/s, 0.00 deletes/s, 158.34 reads/s Number of system rows inserted 0, updated 0, deleted 0, read 8 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================我的
server.cnf（基於 MariaDB InnoDB 4GB 模板）：[client] port = 3306 socket = /var/lib/mysql/mysql.sock [mysqld] character-set-server = utf8 collation-server = utf8_unicode_ci performance_schema port = 3306 socket = /var/lib/mysql/mysql.sock back_log = 50 bind-address = 127.0.0.1 max_connections = 100 max_connect_errors = 10 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 1M max_heap_table_size = 64M read_buffer_size = 2M read_rnd_buffer_size = 16M sort_buffer_size = 8M join_buffer_size = 8M thread_cache_size = 8 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 thread_stack = 240K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M slow_query_log = 1 slow_query_log_file = /var/log/mariadb/slow.log log_error = /var/log/mariadb/error.log log_slow_verbosity = query_plan,explain long_query_time = 1 key_buffer_size = 32M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam-recover-options innodb_buffer_pool_size = 2G innodb_buffer_pool_instances = 2 innodb_data_file_path = ibdata1:10M:autoextend innodb_write_io_threads = 8 innodb_read_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 8M innodb_log_file_size = 256M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 [mysqld_safe] open-files-limit = 8192的輸出
$ cat /proc/meminfoMemTotal: 16267832 kB MemFree: 2878892 kB MemAvailable: 14543648 kB的輸出
ulimit -acore file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 63471 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 4096 virtual memory (kbytes, -v) unlimited file locks (-x) unlimitedMySQLTuner 報告：
[OK] Operating on 64-bit architecture -------- Log file Recommendations ------------------------------------------------------------------ [--] Log file: /var/log/mariadb/error.log(2K) [OK] Log file /var/log/mariadb/error.log exists [OK] Log file /var/log/mariadb/error.log is readable. [OK] Log file /var/log/mariadb/error.log is not empty [OK] Log file /var/log/mariadb/error.log is smaller than 32 Mb [OK] /var/log/mariadb/error.log doesn't contain any warning. [OK] /var/log/mariadb/error.log doesn't contain any error. [--] 1 start(s) detected in /var/log/mariadb/error.log [--] 1) 2017-12-09 15:36:50 139923750996224 [Note] /usr/sbin/mysqld: ready for connections. [--] 1 shutdown(s) detected in /var/log/mariadb/error.log [--] 1) 2017-12-09 15:36:49 140153230964480 [Note] /usr/sbin/mysqld: Shutdown complete -------- Storage Engine Statistics ----------------------------------------------------------------- [--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE [--] Data in MyISAM tables: 589K (Tables: 16) [--] Data in InnoDB tables: 136M (Tables: 1093) [OK] Total fragmented tables: 0 -------- Security Recommendations ------------------------------------------------------------------ [OK] There are no anonymous accounts for any database users [OK] All database users have passwords assigned [--] There are 612 basic passwords in the list. -------- CVE Security Recommendations -------------------------------------------------------------- [OK] NO SECURITY CVE FOUND FOR YOUR VERSION -------- Performance Metrics ----------------------------------------------------------------------- [--] Up for: 3d 8h 55m 54s (1M q [3.970 qps], 35K conn, TX: 2G, RX: 544M) [--] Reads / Writes: 99% / 1% [--] Binary logging is disabled [--] Physical Memory : 15.5G [--] Max MySQL memory : 5.7G [--] Other process memory: 2.2G [--] Total buffers: 2.3G global + 34.2M per thread (100 max threads) [--] P_S Max memory usage: 86M [--] Galera GCache Max memory usage: 0B [OK] Maximum reached memory usage: 2.9G (18.58% of installed RAM) [OK] Maximum possible memory usage: 5.7G (36.90% of installed RAM) [OK] Overall possible memory usage with other process is compatible with memory available [OK] Slow queries: 0% (195/1M) [OK] Highest usage of available connections: 15% (15/100) [OK] Aborted connections: 0.01% (5/35743) [!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance [!!] Query cache may be disabled by default due to mutex contention. [OK] Query cache efficiency: 48.0% (923K cached / 1M selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 11K sorts) [!!] Joins performed without indexes: 1715 [!!] Temporary tables created on disk: 55% (14K on disk / 26K total) [OK] Thread cache hit rate: 99% (19 created / 35K connections) [OK] Table cache hit rate: 24% (2K open / 8K opened) [OK] Open file limit used: 0% (136/16K) [OK] Table locks acquired immediately: 100% (64K immediate / 64K locks) -------- Performance schema ------------------------------------------------------------------------ [--] Memory used by P_S: 86.4M [--] Sys schema isn't installed. -------- ThreadPool Metrics ------------------------------------------------------------------------ [--] ThreadPool stat is enabled. [--] Thread Pool Size: 4 thread(s). [--] Using default value is good enough for your version (10.1.29-MariaDB) -------- MyISAM Metrics ---------------------------------------------------------------------------- [!!] Key buffer used: 18.3% (6M used / 33M cache) [OK] Key buffer size / total MyISAM indexes: 32.0M/233.0K [!!] Read Key buffer hit rate: 92.3% (600 cached / 46 reads) -------- InnoDB Metrics ---------------------------------------------------------------------------- [--] InnoDB is enabled. [--] InnoDB Thread Concurrency: 16 [OK] InnoDB File per table is activated [OK] InnoDB buffer pool / data size: 2.0G/136.0M [!!] Ratio InnoDB log file size / InnoDB Buffer pool size (37.5 %): 256.0M * 3/2.0G should be equal 25% [OK] InnoDB buffer pool instances: 2 [--] InnoDB Buffer Pool Chunk Size not used or defined in your version [OK] InnoDB Read buffer efficiency: 99.94% (12810512 hits/ 12818468 total) [!!] InnoDB Write Log efficiency: 86.04% (35125 hits/ 40825 total) [OK] InnoDB log waits: 0.00% (0 waits / 5700 writes) -------- AriaDB Metrics ---------------------------------------------------------------------------- [--] AriaDB is enabled. [OK] Aria pagecache size / total Aria indexes: 128.0M/1B [!!] Aria pagecache hit rate: 91.8% (144K cached / 11K reads) -------- TokuDB Metrics ---------------------------------------------------------------------------- [--] TokuDB is disabled. -------- XtraDB Metrics ---------------------------------------------------------------------------- [--] XtraDB is disabled. -------- RocksDB Metrics --------------------------------------------------------------------------- [--] RocksDB is disabled. -------- Spider Metrics ---------------------------------------------------------------------------- [--] Spider is disabled. -------- Connect Metrics --------------------------------------------------------------------------- [--] Connect is disabled. -------- Galera Metrics ---------------------------------------------------------------------------- [--] Galera is disabled. -------- Replication Metrics ----------------------------------------------------------------------- [--] Galera Synchronous replication: NO [--] No replication slave(s) for this server. [--] This is a standalone server. -------- Recommendations --------------------------------------------------------------------------- General recommendations: Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1 Adjust your join queries to always utilize indexes When making adjustments, make tmp_table_size/max_heap_table_size equal Reduce your SELECT DISTINCT queries which have no LIMIT clause Consider installing Sys schema from https://github.com/mysql/mysql-sys Read this before changing innodb_log_file_size and/or innodb_log_files_in_group: Variables to adjust: query_cache_size (=0) query_cache_type (=0) join_buffer_size (> 8.0M, or always use indexes with joins) tmp_table_size (> 64M) max_heap_table_size (> 64M) innodb_log_file_size should be (=170M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.來自 pastebin 的其他指標：
好的，我會試一試，因為這是一個可靠的問題。你可以在這裡看到
--Thread 140517442575104 has waited at trx0sys.ic line 103 for 7.0000 seconds the semaphore: X-lock (wait_ex) on RW-latch at 0x7fcca5efd518 '&block->lock' a writer (thread id 140517442575104) has reserved it in mode wait exclusive number of readers 1, waiters flag 0, lock_word: ffffffffffffffff Last time read locked in file buf0flu.cc line 1113 Last time write locked in file trx0sys.ic line 103 Holder thread 0 file not yet reserved line 0 --Thread 140515701942016 has waited at trx0undo.ic line 191 for 7.0000 seconds the semaphore:顯然有些事情發生了，您正在等待 7 秒等待信號量鎖。而且您的旋轉回合似乎也很高。
Spin rounds per wait: 19.28 mutex, 29.79 RW-shared, 98.48 RW-excl所以我們知道你遇到了某種令人討厭的鎖定問題。
innodb_read_io_threads = 64 innodb_write_io_threads = 64這是我對你的問題的猜測。這些是最大值。從文件
每個後台執行緒最多可以處理 256 個掛起的 I/O 請求。
因此，通過在 aio 後端執行的 inno，您可以使用該配置進行 16,384 次排隊讀取和 16,384 次排隊寫入。即使您使用價值 10 億美元的 SAS，我也看不出這是一種生產價值。預設值為 4。您可能對預設值很好。您正在做的是測試您的執行緒調度程序，失去 CPU 時間平衡執行緒，並將 MySQL 推入混亂的互斥鎖中。更糟糕的是，我相信 7s 表明你正處於 innodb 等待的第二階段：也就是說，執行緒實際上是sleep。
更改這些值可能對您有用。
在分析您 17 小時前發布的數據後，請考慮以下事項。
如果可能，獲取 ulimit 打開文件到 65536。目前報告表明 1024 是您的打開文件限制。
my.cnf 中要做的事情
$$ mysqld $$部分可以是添加/更改/刪除
innodb_buffer_pool_dump_at_shutdown=ON # from default of OFF innodb_buffer_pool_load_at_startup=ON # from default of OFF thread_cache_size=100 # from 8 to minimize thread creation all day thread_concurrency=30 # from 8 to keep concurrency throttled to 30% innodb_purge_threads=4 # from default of 1 #read_rnd_buffer_size=16M # disabled to allow default to avoid reading 16M each access #read_buffer_size=2M # disabled to allow default size & avoid reading 2M each access innodb_io_capacity=2000 # from 200 because SSD is capable innodb_io_capacity_max=10000 # from 2000 - if capacity is raised, raise max您的全域狀態報告顯示 A) innodb_buffer_pool_dump_status 正在轉儲和 B) innodb_buffer_pool_load_status 正在載入。這似乎相互矛盾，可能關閉/重新啟動會消除混亂。請讓我知道你的 5 分鐘攤位是否消失。dba.stackexchange.com 問題 75439 提供了有關缺乏足夠清除執行緒是導致停頓的主要原因的線索。您的 innodb_log_buffer_size 和 innodb_log_file_size 大小足以滿足目前活動。將 innodb_buffer_pool_size 增加 1G 將使您為最終將登陸 innodb 的更多表做好準備。如果您願意，我在 my.cnf 中還有更多的事情要做，以改善您的操作。