Storage Engines

InnoDB

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

[ Variables | Buffer Pool | InnoDB Status ]

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2026-04-19 19:57:07 4910 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 31 seconds
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BACKGROUND THREAD
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srv_master_thread loops: 222 srv_active, 0 srv_shutdown, 1833820 srv_idle
srv_master_thread log flush and writes: 1834023
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 3484
OS WAIT ARRAY INFO: signal count 3466
Mutex spin waits 48272, rounds 60682, OS waits 312
RW-shared spins 3666, rounds 104031, OS waits 3042
RW-excl spins 350, rounds 654, OS waits 9
Spin rounds per wait: 1.26 mutex, 28.38 RW-shared, 1.87 RW-excl
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TRANSACTIONS
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Trx id counter 18293151
Purge done for trx's n:o < 18293149 undo n:o < 0 state: running but idle
History list length 9
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 2943, OS thread handle 0x4910, query id 50081 localhost 127.0.0.1 root init
SHOW ENGINE INNODB STATUS
---TRANSACTION 18279171, not started
MySQL thread id 1, OS thread handle 0x1360, query id 0 Waiting for requests
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FILE I/O
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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, 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
24065 OS file reads, 2100 OS file writes, 1120 OS fsyncs
1.45 reads/s, 16384 avg bytes/read, 4.00 writes/s, 2.19 fsyncs/s
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INSERT BUFFER AND ADAPTIVE HASH INDEX
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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
1.52 hash searches/s, 92.29 non-hash searches/s
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LOG
---
Log sequence number 877229005
Log flushed up to   877229005
Pages flushed up to 877215603
Last checkpoint at  877202899
Max checkpoint age    7782360
Checkpoint age target 7539162
Modified age          13402
Checkpoint age        26106
0 pending log writes, 0 pending chkp writes
550 log i/o's done, 1.26 log i/o's/second
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BUFFER POOL AND MEMORY
----------------------
Total memory allocated 17203200; in additional pool allocated 0
Total memory allocated by read views 2456
Internal hash tables (constant factor + variable factor)
    Adaptive hash index 297300 	(276764 + 20536)
    Page hash           9068 (buffer pool 0 only)
    Dictionary cache    356923 	(69928 + 286995)
    File system         440936 	(406136 + 34800)
    Lock system         21812 	(21188 + 624)
    Recovery system     0 	(0 + 0)
Dictionary memory allocated 286995
Buffer pool size        1023
Buffer pool size, bytes 16760832
Free buffers            766
Database pages          256
Old database pages      0
Modified db pages       82
Percent of dirty pages(LRU & free pages): 8.016
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 7, not young 138582
0.00 youngs/s, 0.00 non-youngs/s
Pages read 23833, created 15, written 1328
1.45 reads/s, 0.03 creates/s, 2.32 writes/s
Buffer pool hit rate 994 / 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[229]:cur[0], 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 id 4340, state: sleeping
Number of rows inserted 0, updated 315, deleted 0, read 1429610
0.00 inserts/s, 1.03 updates/s, 0.00 deletes/s, 5.16 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 6
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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