หากต้องการดูการล็อกส่วนกลางใน MySQL (Innodb) ให้ใช้คำสั่ง SHOW แบบสอบถามด้านล่างแสดงการล็อคส่วนกลางและเจ้าของล็อคและพนักงานเสิร์ฟ ข้อความค้นหาต่อไปนี้จะแสดงรหัสธุรกรรมและเกี่ยวข้องกับ Innodb มากขึ้น
แบบสอบถามมีดังนี้:
mysql> SHOW ENGINE INNODB STATUS\G
ต่อไปนี้เป็นผลลัพธ์:
*************************** 1. row *************************** Type: InnoDB Name: Status: ===================================== 2019-01-23 14:46:58 0x2914 INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 23 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 87 srv_active, 0 srv_shutdown, 51953 srv_idle srv_master_thread log flush and writes: 0 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 244 OS WAIT ARRAY INFO: signal count 241 RW-shared spins 23, rounds 37, OS waits 14 RW-excl spins 16, rounds 380, OS waits 9 RW-sx spins 1, rounds 4, OS waits 0 Spin rounds per wait: 1.61 RW-shared, 23.75 RW-excl, 4.00 RW-sx ------------ TRANSACTIONS ------------ Trx id counter 60219 Purge done for trx's n:o < 60218 undo n:o < 0 state: running but idle History list length 32 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 284507225290560, not started 0 lock struct(s), heap size 1136, 0 row lock(s) -------- FILE I/O -------- I/O thread 0 state: wait Windows aio (insert buffer thread) I/O thread 1 state: wait Windows aio (log thread) I/O thread 2 state: wait Windows aio (read thread) I/O thread 3 state: wait Windows aio (read thread) I/O thread 4 state: wait Windows aio (read thread) I/O thread 5 state: wait Windows aio (read thread) I/O thread 6 state: wait Windows aio (write thread) I/O thread 7 state: wait Windows aio (write thread) I/O thread 8 state: wait Windows aio (write thread) I/O thread 9 state: wait Windows aio (write thread) Pending normal aio reads: [0, 0, 0, 0] , aio writes: [0, 0, 0, 0] , ibuf aio reads:, log i/o's:, sync i/o's: Pending flushes (fsync) log: 0; buffer pool: 0 2134 OS file reads, 2843 OS file writes, 1186 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 0, seg size 2, 0 merges merged operations: insert 0, delete mark 0, delete 0 discarded operations: insert 0, delete mark 0, delete 0 Hash table size 2267, node heap has 0 buffer(s) Hash table size 2267, node heap has 1 buffer(s) Hash table size 2267, node heap has 1 buffer(s) Hash table size 2267, node heap has 1 buffer(s) Hash table size 2267, node heap has 0 buffer(s) Hash table size 2267, node heap has 0 buffer(s) Hash table size 2267, node heap has 0 buffer(s) Hash table size 2267, node heap has 0 buffer(s) 0.00 hash searches/s, 0.00 non-hash searches/s --- LOG --- Log sequence number 44174557 Log buffer assigned up to 44174557 Log buffer completed up to 44174557 Log written up to 44174557 Log flushed up to 44174557 Added dirty pages up to 44174557 Pages flushed up to 44174557 Last checkpoint at 44174557 1117 log i/o's done, 0.00 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total large memory allocated 8585216 Dictionary memory allocated 503201 Buffer pool size 512 Free buffers 253 Database pages 256 Old database pages 0 Modified db pages 0 Pending reads 0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 0, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 2111, created 215, written 1437 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: 256, 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 Process ID=8992, Main thread ID=00000000000029F4 , state=sleeping Number of rows inserted 247, updated 512, deleted 19, read 6593 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================ 1 row in set (0.00 sec)
