Storage engines

InnoDB

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

[ Variables | Buffer Pool | InnoDB Status ]

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2026-09-25 20:51:00 0x3c50 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 36 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 9209 srv_active, 0 srv_shutdown, 37485 srv_idle
srv_master_thread log flush and writes: 46694
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SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 285208
OS WAIT ARRAY INFO: signal count 258258
RW-shared spins 665339, rounds 11915674, OS waits 274008
RW-excl spins 60351, rounds 742525, OS waits 4502
RW-sx spins 4, rounds 101, OS waits 3
Spin rounds per wait: 17.91 RW-shared, 12.30 RW-excl, 25.25 RW-sx
------------
TRANSACTIONS
------------
Trx id counter 7767379
Purge done for trx's n:o < 7767376 undo n:o < 0 state: running but idle
History list length 2
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 284268549145152, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549136816, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549120144, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549132648, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549128480, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549124312, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 284268549140984, ACTIVE 0 sec
mysql tables in use 2, locked 0
0 lock struct(s), heap size 1128, 0 row lock(s)
MySQL thread id 82892, OS thread handle 11668, query id 13155857 localhost ::1 root Sending data
SELECT DISTINCT
            e.stud_id, e.stud_name, e.course, e.year, e.section, e.sy, e.sems, 
            sr.gender
        FROM enrolled e
        LEFT JOIN student_record sr ON e.stud_id = sr.stud_id
        WHERE 1=1
     AND e.sy = '2026-2027' AND (e.stud_id LIKE '%CEN%' OR e.stud_name LIKE '%CEN%') ORDER BY e.sy DESC, e.sems DESC, e.stud_name ASC
Trx read view will not see trx with id >= 7767375, sees < 7767375
--------
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
2782475 OS file reads, 130041 OS file writes, 69695 OS fsyncs
432.96 reads/s, 16384 avg bytes/read, 27.50 writes/s, 11.25 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 15, seg size 17, 1849 merges
merged operations:
 insert 1971, delete mark 12, delete 2
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 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)
Hash table size 4441, node heap has 1 buffer(s)
30.89 hash searches/s, 84.36 non-hash searches/s
---
LOG
---
Log sequence number 4690235695
Log flushed up to   4690235695
Pages flushed up to 4690233291
Last checkpoint at  4690191747
0 pending log flushes, 0 pending chkp writes
35625 log i/o's done, 7.14 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 33554432
Dictionary memory allocated 618488
Buffer pool size   1003
Free buffers       0
Database pages     995
Old database pages 386
Modified db pages  5
Percent of dirty pages(LRU & free pages): 0.502
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 291530, not young 83177844
21.50 youngs/s, 2950.03 non-youngs/s
Pages read 2782226, created 1050, written 82378
432.96 reads/s, 0.19 creates/s, 18.81 writes/s
Buffer pool hit rate 920 / 1000, young-making rate 3 / 1000 not 544 / 1000
Pages read ahead 347.10/s, evicted without access 2.11/s, Random read ahead 0.00/s
LRU len: 995, unzip_LRU len: 0
I/O sum[4711]:cur[384], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
1 read views open inside InnoDB
Process ID=4336, Main thread ID=6540, state: sleeping
Number of rows inserted 851, updated 21956, deleted 258, read 383421691
0.03 inserts/s, 5.86 updates/s, 0.03 deletes/s, 38349.80 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 85217
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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