Storage engines
InnoDB
Supports transactions, row-level locking, foreign keys and encryption for tables
[
Variables
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Buffer Pool
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InnoDB Status
]
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2026-06-25 19:25:39 0x1c38 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 18 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 1013567 srv_active, 0 srv_shutdown, 234862 srv_idle
srv_master_thread log flush and writes: 1248429
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 95354978
OS WAIT ARRAY INFO: signal count 14462612
RW-shared spins 272445, rounds 7569100, OS waits 233490
RW-excl spins 22638, rounds 521344, OS waits 14930
RW-sx spins 408, rounds 7364, OS waits 161
Spin rounds per wait: 27.78 RW-shared, 23.03 RW-excl, 18.05 RW-sx
------------------------
LATEST FOREIGN KEY ERROR
------------------------
2026-06-17 04:45:37 0x3270 Transaction:
TRANSACTION 17388149, ACTIVE 0 sec updating or deleting
mysql tables in use 1, locked 1
4 lock struct(s), heap size 1128, 2 row lock(s), undo log entries 1
MySQL thread id 3317039, OS thread handle 12912, query id 288153452 122.179.243.215 AccessAdmin Updating
UPDATE `marketing_ops_testing`.`department` SET `DeptCode` = 'IT02' WHERE (`DeptCode` = '1')
Foreign key constraint fails for table `marketing_ops_testing`.`resourceemployment`:
,
CONSTRAINT `fk_DeptCode` FOREIGN KEY (`DeptCode`) REFERENCES `department` (`DeptCode`)
Trying to delete or update in parent table, in index PRIMARY tuple:
DATA TUPLE: 4 fields;
0: len 1; hex 31; asc 1;;
1: len 6; hex 000001095275; asc Ru;;
2: len 7; hex 17000001e7205d; asc ];;
3: len 20; hex 536f66747761726520446576656c6f706d656e74; asc Software Development;;
But in child table `marketing_ops_testing`.`resourceemployment`, in index fk_DeptCode, there is a record:
PHYSICAL RECORD: n_fields 2; compact format; info bits 0
0: len 1; hex 31; asc 1;;
1: len 6; hex 0000000304a4; asc ;;
------------
TRANSACTIONS
------------
Trx id counter 20507218
Purge done for trx's n:o < 20507218 undo n:o < 0 state: running but idle
History list length 5
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 283891465912680, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283891465908512, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283891465904344, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283891465925184, not started flushing log
mysql tables in use 1, locked 1
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283891465921016, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283891465900176, not started flushing log
mysql tables in use 1, locked 1
0 lock struct(s), heap size 1128, 0 row lock(s)
--------
FILE I/O
--------
I/O thread 0 state: native aio handle (insert buffer thread)
I/O thread 1 state: native aio handle (log thread)
I/O thread 2 state: native aio handle (read thread)
I/O thread 3 state: native aio handle (read thread)
I/O thread 4 state: native aio handle (read thread)
I/O thread 5 state: native aio handle (read thread)
I/O thread 6 state: native aio handle (write thread)
I/O thread 7 state: native aio handle (write thread)
I/O thread 8 state: native aio handle (write thread)
I/O thread 9 state: native aio handle (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: 1; buffer pool: 0
35593323 OS file reads, 14297053 OS file writes, 8900400 OS fsyncs
29.22 reads/s, 16384 avg bytes/read, 12.72 writes/s, 7.72 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 12, seg size 14, 209 merges
merged operations:
insert 116, delete mark 1289, delete 358
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 2 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
244.76 hash searches/s, 95.38 non-hash searches/s
---
LOG
---
Log sequence number 13084718883
Log flushed up to 13084716608
Pages flushed up to 13084713186
Last checkpoint at 13084704535
1 pending log flushes, 0 pending chkp writes
4351600 log i/o's done, 4.06 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 33554432
Dictionary memory allocated 678584
Buffer pool size 1003
Free buffers 714
Database pages 280
Old database pages 0
Modified db pages 11
Percent of dirty pages(LRU & free pages): 1.106
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 22396, not young 3062627
0.00 youngs/s, 0.00 non-youngs/s
Pages read 35593037, created 140096, written 7936677
29.22 reads/s, 0.06 creates/s, 7.00 writes/s
Buffer pool hit rate 990 / 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: 280, unzip_LRU len: 0
I/O sum[2130]:cur[37], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
0 read views open inside InnoDB
Process ID=4584, Main thread ID=5176, state: sleeping
Number of rows inserted 1320, updated 2675784, deleted 2198, read 17587573382
0.00 inserts/s, 2.56 updates/s, 0.00 deletes/s, 18760.96 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 331199
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================
