Storage engines

InnoDB

Supports transactions, row-level locking, foreign keys and encryption for tables

[ Variables | Buffer Pool | InnoDB Status ]

=====================================
2026-05-16 17:35:35 0x7bf0 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 19 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 662 srv_active, 0 srv_shutdown, 118156 srv_idle
srv_master_thread log flush and writes: 118818
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 4086
OS WAIT ARRAY INFO: signal count 2450
RW-shared spins 2618, rounds 65676, OS waits 2099
RW-excl spins 3901, rounds 14385, OS waits 50
RW-sx spins 93, rounds 852, OS waits 9
Spin rounds per wait: 25.09 RW-shared, 3.69 RW-excl, 9.16 RW-sx
------------------------
LATEST FOREIGN KEY ERROR
------------------------
2026-05-15 08:57:35 0x7ef4 Error in foreign key constraint of table `seminar_system`.`payments`:
Alter  table `seminar_system`.`payments` with foreign key constraint failed. Referenced table `seminar_system`.`registrations` not found in the data dictionary near ' foreign key (`registration_id`) references `registrations` (`id`) on delete cascade'.
------------
TRANSACTIONS
------------
Trx id counter 30108
Purge done for trx's n:o < 30108 undo n:o < 0 state: running but idle
History list length 2
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 283430068961928, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068957760, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068953592, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068949424, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068945256, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068941088, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068936920, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 283430068932752, not started
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: 0; buffer pool: 0
6293 OS file reads, 16392 OS file writes, 8164 OS fsyncs
2.26 reads/s, 16384 avg bytes/read, 6.68 writes/s, 3.84 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 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 0 buffer(s)
Hash table size 4441, node heap has 0 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
Hash table size 4441, node heap has 0 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)
11.68 hash searches/s, 31.52 non-hash searches/s
---
LOG
---
Log sequence number 12282948
Log flushed up to   12282928
Pages flushed up to 12240737
Last checkpoint at  12236676
0 pending log flushes, 0 pending chkp writes
5299 log i/o's done, 2.89 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 33554432
Dictionary memory allocated 167768
Buffer pool size   1003
Free buffers       738
Database pages     260
Old database pages 0
Modified db pages  68
Percent of dirty pages(LRU & free pages): 6.807
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 81, not young 737
0.00 youngs/s, 0.00 non-youngs/s
Pages read 6238, created 762, written 10166
2.26 reads/s, 0.21 creates/s, 3.37 writes/s
Buffer pool hit rate 981 / 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: 260, unzip_LRU len: 0
I/O sum[859]:cur[3], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
0 read views open inside InnoDB
Process ID=23056, Main thread ID=32240, state: sleeping
Number of rows inserted 106, updated 1196, deleted 27, read 2744187
0.00 inserts/s, 2.11 updates/s, 0.00 deletes/s, 11.79 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 1143
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================