Storage engines
InnoDB
Percona-XtraDB, Supports transactions, row-level locking, foreign keys and encryption for tables
[
Variables
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Buffer Pool
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InnoDB Status
]
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2026-07-21 19:58:19 7fbbdd126b00 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 34 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 4835 srv_active, 0 srv_shutdown, 131148 srv_idle
srv_master_thread log flush and writes: 135982
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 3640
OS WAIT ARRAY INFO: signal count 3532
Mutex spin waits 14693, rounds 124615, OS waits 1824
RW-shared spins 1643, rounds 49133, OS waits 1637
RW-excl spins 13, rounds 4322, OS waits 143
Spin rounds per wait: 8.48 mutex, 29.90 RW-shared, 332.46 RW-excl
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TRANSACTIONS
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Trx id counter 100719
Purge done for trx's n:o < 100718 undo n:o < 0 state: running but idle
History list length 28
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 22628, OS thread handle 0x7fbbdd126b00, query id 364592 localhost root init
SHOW ENGINE INNODB STATUS
---TRANSACTION 100718, not started
MySQL thread id 22627, OS thread handle 0x7fbbdd207b00, query id 364586 localhost pma
---TRANSACTION 2819, not started
MySQL thread id 1, OS thread handle 0x7fbbec5cdb00, query id 0 Waiting for requests
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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, 0] , aio writes: 0 [0, 0, 0, 0] ,
ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
Pending flushes (fsync) log: 0; buffer pool: 0
11817 OS file reads, 36688 OS file writes, 23028 OS fsyncs
2.76 reads/s, 16384 avg bytes/read, 8.85 writes/s, 4.79 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
5.24 hash searches/s, 21.88 non-hash searches/s
---
LOG
---
Log sequence number 13732198
Log flushed up to 13732198
Pages flushed up to 13712481
Last checkpoint at 13709380
Max checkpoint age 7782360
Checkpoint age target 7539162
Modified age 19717
Checkpoint age 22818
0 pending log writes, 0 pending chkp writes
10704 log i/o's done, 2.50 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 17580032; in additional pool allocated 0
Total memory allocated by read views 304
Internal hash tables (constant factor + variable factor)
Adaptive hash index 297776 (277192 + 20584)
Page hash 18136 (buffer pool 0 only)
Dictionary cache 163240 (70736 + 92504)
File system 834872 (812272 + 22600)
Lock system 43456 (42376 + 1080)
Recovery system 0 (0 + 0)
Dictionary memory allocated 92504
Buffer pool size 1023
Buffer pool size, bytes 16760832
Free buffers 766
Database pages 256
Old database pages 0
Modified db pages 35
Percent of dirty pages(LRU & free pages): 3.421
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 11783, created 431, written 36777
2.76 reads/s, 0.21 creates/s, 9.32 writes/s
Buffer pool hit rate 971 / 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: 256, unzip_LRU len: 0
I/O sum[418]: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
0 RW transactions active inside InnoDB
0 RO transactions active inside InnoDB
0 out of 1000 descriptors used
Main thread process no. 277, id 140444910425856, state: sleeping
Number of rows inserted 3, updated 8919, deleted 0, read 31344
0.00 inserts/s, 2.21 updates/s, 0.00 deletes/s, 6.03 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 126
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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