Storage engines

InnoDB

Supports transactions, row-level locking, and foreign keys

[ Variable | Bufferpool | InnoDB status ]

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2026-04-05 21:42:46 0x7fc45005e700 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 47 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 76 srv_active, 0 srv_shutdown, 641 srv_idle
srv_master_thread log flush and writes: 0
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 614
OS WAIT ARRAY INFO: signal count 537
RW-shared spins 63, rounds 117, OS waits 54
RW-excl spins 225, rounds 1847, OS waits 36
RW-sx spins 1, rounds 30, OS waits 1
Spin rounds per wait: 1.86 RW-shared, 8.21 RW-excl, 30.00 RW-sx
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LATEST FOREIGN KEY ERROR
------------------------
2026-04-05 21:38:25 0x7fc4500a6700 Transaction:
TRANSACTION 10579, ACTIVE 0 sec inserting
mysql tables in use 1, locked 1
3 lock struct(s), heap size 1136, 1 row lock(s), undo log entries 1
MySQL thread id 3281, OS thread handle 140481133176576, query id 92320 192.168.30.20 root update
INSERT IGNORE INTO `Receipt_position` (`Position_id`, `Receipt_id`, `Product_id`, `Quantity`, `Unit_Price`, `Amount_before_discount`, `Discount_Amount`, `Discount_Percent`, `VAT_Rate_Percent`, `VAT_Amount`, `Line_Total`) 
VALUES (3, 2, 3, 3, 35.00, 105.00, 0.00, 0.00, 20, 17.50, 105.00)
Foreign key constraint fails for table `bakery_sales`.`Receipt_position`:
,
  CONSTRAINT `Receipt_position_ibfk_1` FOREIGN KEY (`Receipt_id`) REFERENCES `Receipt` (`Receipt_id`)
Trying to add in child table, in index Receipt_id tuple:
DATA TUPLE: 2 fields;
 0: len 4; hex 80000002; asc     ;;
 1: len 4; hex 80000003; asc     ;;

But in parent table `bakery_sales`.`Receipt`, in index PRIMARY,
the closest match we can find is record:
PHYSICAL RECORD: n_fields 1; compact format; info bits 0
 0: len 8; hex 696e66696d756d00; asc infimum ;;

------------
TRANSACTIONS
------------
Trx id counter 10601
Purge done for trx's n:o < 10600 undo n:o < 0 state: running but idle
History list length 2
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 421956296563304, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421956296562432, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
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FILE I/O
--------
I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
I/O thread 1 state: waiting for completed aio requests (log thread)
I/O thread 2 state: waiting for completed aio requests (read thread)
I/O thread 3 state: waiting for completed aio requests (read thread)
I/O thread 4 state: waiting for completed aio requests (read thread)
I/O thread 5 state: waiting for completed aio requests (read thread)
I/O thread 6 state: waiting for completed aio requests (write thread)
I/O thread 7 state: waiting for completed aio requests (write thread)
I/O thread 8 state: waiting for completed aio requests (write thread)
I/O thread 9 state: waiting for completed aio requests (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
1845 OS file reads, 4914 OS file writes, 1521 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 0.23 writes/s, 0.15 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 34679, node heap has 2 buffer(s)
Hash table size 34679, node heap has 2 buffer(s)
Hash table size 34679, node heap has 2 buffer(s)
Hash table size 34679, node heap has 2 buffer(s)
Hash table size 34679, node heap has 5 buffer(s)
Hash table size 34679, node heap has 3 buffer(s)
Hash table size 34679, node heap has 3 buffer(s)
Hash table size 34679, node heap has 8 buffer(s)
2608.20 hash searches/s, 2115.93 non-hash searches/s
---
LOG
---
Log sequence number          52899387
Log buffer assigned up to    52899387
Log buffer completed up to   52899387
Log written up to            52899387
Log flushed up to            52899387
Added dirty pages up to      52899387
Pages flushed up to          52899387
Last checkpoint at           52899387
2234 log i/o's done, 0.06 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 137363456
Dictionary memory allocated 596522
Buffer pool size   8192
Free buffers       6224
Database pages     1941
Old database pages 734
Modified db pages  0
Pending reads      0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 1387, not young 1761
0.00 youngs/s, 0.00 non-youngs/s
Pages read 1684, created 803, written 2173
0.00 reads/s, 0.00 creates/s, 0.00 writes/s
Buffer pool hit rate 1000 / 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: 1941, unzip_LRU len: 0
I/O sum[6]:cur[0], unzip sum[0]:cur[0]
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ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
0 read views open inside InnoDB
Process ID=368, Main thread ID=140480810530560 , state=sleeping
Number of rows inserted 148586, updated 3287, deleted 1806, read 2037673
0.00 inserts/s, 0.02 updates/s, 0.00 deletes/s, 3069.76 reads/s
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END OF INNODB MONITOR OUTPUT
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