MySQL có thể phát hiện bế tắc không?
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Sau khi thực hiện câu lệnh trên, chúng ta hãy thực hiện cú pháp bên dưới để hiển thị tất cả nhật ký khóa chết - Show show engine innodb status; Hãy để chúng tôi thực hiện cú pháp trên - mysql> set global innodb_print_all_deadlocks=1; Query OK, 0 rows affected (0.00 sec) mysql> show engine innodb status; Điều này sẽ tạo ra đầu ra sau - 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| Type | Name | Status | 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| InnoDB | | ===================================== 2019-05-03 16:44:53 0xf9c INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 26 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 38 srv_active, 0 srv_shutdown, 5120 srv_idle srv_master_thread log flush and writes: 0 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 127 OS WAIT ARRAY INFO: signal count 127 RW-shared spins 1, rounds 2, OS waits 1 RW-excl spins 8, rounds 198, OS waits 6 RW-sx spins 0, rounds 0, OS waits 0 Spin rounds per wait: 2.00 RW-shared, 24.75 RW-excl, 0.00 RW-sx ------------ TRANSACTIONS ------------ Trx id counter 136292 Purge done for trx's n:o < 136292 undo n:o < 0 state: running but idle History list length 27 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 283092444694336, 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 1947 OS file reads, 971 OS file writes, 397 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 138401, node heap has 4 buffer(s) Hash table size 138401, node heap has 1 buffer(s) Hash table size 138401, node heap has 17 buffer(s) Hash table size 138401, node heap has 3 buffer(s) Hash table size 138401, node heap has 1 buffer(s) Hash table size 138401, node heap has 0 buffer(s) Hash table size 138401, node heap has 0 buffer(s) Hash table size 138401, node heap has 0 buffer(s) 0.00 hash searches/s, 0.00 non-hash searches/s --- LOG --- Log sequence number 80212677 Log buffer assigned up to 80212677 Log buffer completed up to 80212677 Log written up to 80212677 Log flushed up to 80212677 Added dirty pages up to 80212677 Pages flushed up to 80212677 Last checkpoint at 80212677 228 log i/o's done, 0.00 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total large memory allocated 549453824 Dictionary memory allocated 415895 Buffer pool size 32768 Free buffers 30848 Database pages 1894 Old database pages 717 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 1740, created 154, written 622 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: 1894, 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=4564, Main thread ID=000000000000191C , state=sleeping Number of rows inserted 80, updated 355, deleted 12, read 83378 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================ | 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1 row in set (0.00 sec) MySQL xử lý bế tắc như thế nào?Với việc triển khai công cụ InnoDB, MySQL cung cấp một cách đơn giản và dễ dàng để chẩn đoán cũng như hiểu rõ hơn về các bế tắc đó. Công cụ Innodb tự động phát hiện và hủy một trong các giao dịch, cho phép một giao dịch tiếp tục và đưa ra lỗi trên giao dịch đã được khôi phục .
Làm cách nào để tắt bế tắc trong MySQL?Tắt phát hiện bế tắc
. Phát hiện bế tắc có thể bị vô hiệu hóa bằng cách sử dụng biến innodb_deadlock_detect .
Làm cách nào để mô phỏng bế tắc trong MySQL?Ví dụ bế tắc có 3 bước và tôi nghi ngờ bạn có thể đã bỏ lỡ bước cuối cùng. . T1. lựa chọn T2. xóa bỏ. T2 phải đợi T1 bây giờ. Chờ đợi có nghĩa là MySQL hiện vẫn nhìn thấy một cách khả thi mà cả T1 và T2 đều có thể kết thúc thành công. . T1. xóa bỏ. Điều này sẽ dẫn đến bế tắc trong T2 Làm cách nào để kiểm tra bế tắc trong mssql?DM_EXEC_REQUESTS chế độ xem quản lý động. Trong câu lệnh này, cộtblocking_session_id cung cấp cho bạn session_id của kết nối đang chặn và cột wait_type cung cấp cho bạn loại chờ gây ra bế tắc. Sau khi nhận được blocks_session_id, bạn có thể sử dụng một dmv SYS khác |
