Hi, I have two servers Mysql 5.5 with master to master replication. The second server failed and I needed to remove it to repair the operating system. After this incident the application users have been notice that the application response have been very slow.
Both servers have RAID 1 (mirroring) managed by operating system. Could you help me to understand what's happening? Follow the innodb status: mysql> show engine innodb status \G *************************** 1. row *************************** Type: InnoDB Name: Status: ===================================== 141105 17:43:07 INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 36 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 4704 1_second, 4703 sleeps, 470 10_second, 2 background, 2 flush srv_master_thread log flush and writes: 4740 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 194, signal count 201 Mutex spin waits 280, rounds 819, OS waits 9 RW-shared spins 82, rounds 2324, OS waits 74 RW-excl spins 8, rounds 3533, OS waits 110 Spin rounds per wait: 2.92 mutex, 28.34 RW-shared, 441.62 RW-excl ------------ TRANSACTIONS ------------ Trx id counter 82EC Purge done for trx's n:o < 7A75 undo n:o < 0 History list length 32 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 0, not started MySQL thread id 301, OS thread handle 0x7ff94db71700, query id 32201 localhost root show engine innodb status ---TRANSACTION 80D6, not started MySQL thread id 41, OS thread handle 0x7ff94dba2700, query id 29440 localhost 127.0.0.1 root ---TRANSACTION 82EB, not started MySQL thread id 40, OS thread handle 0x7ff94dbd3700, query id 32200 localhost 127.0.0.1 root -------- FILE I/O -------- I/O thread 0 state: waiting for i/o request (insert buffer thread) I/O thread 1 state: waiting for i/o request (log thread) I/O thread 2 state: waiting for i/o request (read thread) I/O thread 3 state: waiting for i/o request (read thread) I/O thread 4 state: waiting for i/o request (read thread) I/O thread 5 state: waiting for i/o request (read thread) I/O thread 6 state: waiting for i/o request (write thread) I/O thread 7 state: waiting for i/o request (write thread) I/O thread 8 state: waiting for i/o request (write thread) I/O thread 9 state: waiting for i/o request (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 19995 OS file reads, 12493 OS file writes, 8901 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 2140, seg size 2142, 122 merges merged operations: insert 482, delete mark 661, delete 2 discarded operations: insert 0, delete mark 0, delete 0 Hash table size 276707, node heap has 671 buffer(s) 1.06 hash searches/s, 5.28 non-hash searches/s --- LOG --- Log sequence number 4276155092 Log flushed up to 4276155092 Last checkpoint at 4276155092 0 pending log writes, 0 pending chkp writes 8644 log i/o's done, 0.00 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total memory allocated 137363456; in additional pool allocated 0 Dictionary memory allocated 2978314 Buffer pool size 8192 Free buffers 0 Database pages 7521 Old database pages 2756 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 13227, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 20400, created 52, written 5785 0.00 reads/s, 0.00 creates/s, 0.00 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: 7521, 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 1 read views open inside InnoDB Main thread process no. 870, id 140708344538880, state: sleeping Number of rows inserted 4256, updated 8, deleted 3101, read 6737576 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 2.11 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================
