Storage engines

InnoDB

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

[ Variables | Buffer Pool | InnoDB Status ]

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2026-07-30 16:38:19 0x7fd7a815a640 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 4 seconds
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BACKGROUND THREAD
-----------------
srv_master_thread loops: 1115 srv_active, 0 srv_shutdown, 154697 srv_idle
srv_master_thread log flush and writes: 155758
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 22985
OS WAIT ARRAY INFO: signal count 18861
RW-shared spins 12900, rounds 95942, OS waits 1462
RW-excl spins 12362, rounds 151863, OS waits 2978
RW-sx spins 134, rounds 3083, OS waits 87
Spin rounds per wait: 7.44 RW-shared, 12.28 RW-excl, 23.01 RW-sx
------------------------
LATEST FOREIGN KEY ERROR
------------------------
2026-07-28 23:04:36 0x7fd7ac9b4640  Cannot drop table `cu_theses`.`theses`
because it is referenced by `cu_theses`.`researchers`
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TRANSACTIONS
------------
Trx id counter 125594
Purge done for trx's n:o < 125594 undo n:o < 0 state: running but idle
History list length 7
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 422039217803528, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 422039217799312, 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: waiting for i/o request (insert buffer thread)
I/O thread 1 state: waiting for i/o request (log thread)
I/O thread 2 state: waiting for i/o request (read thread)
I/O thread 3 state: waiting for i/o request (read thread)
I/O thread 4 state: waiting for i/o request (read thread)
I/O thread 5 state: waiting for i/o request (read thread)
I/O thread 6 state: waiting for i/o request (write thread)
I/O thread 7 state: waiting for i/o request (write thread)
I/O thread 8 state: waiting for i/o request (write thread)
I/O thread 9 state: waiting for i/o request (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
224601 OS file reads, 132697 OS file writes, 50131 OS fsyncs
11.50 reads/s, 16384 avg bytes/read, 27.74 writes/s, 10.00 fsyncs/s
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INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 17, seg size 19, 347 merges
merged operations:
 insert 4914, delete mark 1, delete 0
discarded operations:
 insert 0, delete mark 0, delete 0
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 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 0 buffer(s)
Hash table size 4441, node heap has 1 buffer(s)
33.74 hash searches/s, 75.23 non-hash searches/s
---
LOG
---
Log sequence number 686038893
Log flushed up to   686038873
Pages flushed up to 686037893
Last checkpoint at  686012552
0 pending log flushes, 0 pending chkp writes
7345 log i/o's done, 7.75 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 33554432
Dictionary memory allocated 671000
Buffer pool size   1002
Free buffers       738
Database pages     257
Old database pages 0
Modified db pages  3
Percent of dirty pages(LRU & free pages): 0.301
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 3722, not young 6343162
0.00 youngs/s, 0.00 non-youngs/s
Pages read 224154, created 11808, written 104377
11.50 reads/s, 0.25 creates/s, 19.25 writes/s
Buffer pool hit rate 964 / 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: 257, unzip_LRU len: 0
I/O sum[82]:cur[41], 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=106707, Main thread ID=140563777041984, state: sleeping
Number of rows inserted 55369, updated 3732, deleted 580, read 9045127
0.00 inserts/s, 6.75 updates/s, 0.00 deletes/s, 46.99 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 69811
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 63.73 reads/s
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END OF INNODB MONITOR OUTPUT
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