Storage engines

InnoDB

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

[ Variables | Buffer Pool | InnoDB Status ]

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2026-05-16 18:31:04 0x8810 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 38 seconds
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BACKGROUND THREAD
-----------------
srv_master_thread loops: 780 srv_active, 0 srv_shutdown, 121338 srv_idle
srv_master_thread log flush and writes: 122118
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 4965
OS WAIT ARRAY INFO: signal count 2581
RW-shared spins 2672, rounds 67275, OS waits 2149
RW-excl spins 3904, rounds 14446, OS waits 52
RW-sx spins 93, rounds 852, OS waits 9
Spin rounds per wait: 25.18 RW-shared, 3.70 RW-excl, 9.16 RW-sx
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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'.
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TRANSACTIONS
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Trx id counter 31552
Purge done for trx's n:o < 31552 undo n:o < 0 state: running but idle
History list length 8
LIST OF TRANSACTIONS FOR EACH SESSION:
---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)
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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
7712 OS file reads, 19258 OS file writes, 9465 OS fsyncs
1.39 reads/s, 16384 avg bytes/read, 3.66 writes/s, 2.05 fsyncs/s
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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)
6.32 hash searches/s, 15.24 non-hash searches/s
---
LOG
---
Log sequence number 13211985
Log flushed up to   13211965
Pages flushed up to 13188226
Last checkpoint at  13186121
0 pending log flushes, 0 pending chkp writes
6231 log i/o's done, 1.55 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 33554432
Dictionary memory allocated 167768
Buffer pool size   1003
Free buffers       737
Database pages     261
Old database pages 0
Modified db pages  63
Percent of dirty pages(LRU & free pages): 6.306
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 7657, created 793, written 11927
1.39 reads/s, 0.08 creates/s, 1.89 writes/s
Buffer pool hit rate 976 / 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: 261, unzip_LRU len: 0
I/O sum[332]:cur[2], unzip sum[0]:cur[0]
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ROW OPERATIONS
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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 1918, deleted 27, read 2753186
0.00 inserts/s, 1.21 updates/s, 0.00 deletes/s, 5.82 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 1224
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
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END OF INNODB MONITOR OUTPUT
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