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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2026-10-24 07:11:02 1130 INNODB MONITOR OUTPUT
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Per second averages calculated from the last 44 seconds
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BACKGROUND THREAD
-----------------
srv_master_thread loops: 497 srv_active, 0 srv_shutdown, 231226 srv_idle
srv_master_thread log flush and writes: 231723
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SEMAPHORES
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OS WAIT ARRAY INFO: reservation count 652
OS WAIT ARRAY INFO: signal count 632
Mutex spin waits 81774, rounds 73837, OS waits 317
RW-shared spins 330, rounds 9888, OS waits 311
RW-excl spins 5, rounds 420, OS waits 12
Spin rounds per wait: 0.90 mutex, 29.96 RW-shared, 84.00 RW-excl
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TRANSACTIONS
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Trx id counter 79040
Purge done for trx's n:o < 79014 undo n:o < 0 state: running but idle
History list length 27
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started
MySQL thread id 2729, OS thread handle 0x1130, query id 49753 localhost 127.0.0.1 root init
SHOW ENGINE INNODB STATUS
---TRANSACTION 79039, not started
MySQL thread id 2728, OS thread handle 0x1130, query id 49747 localhost 127.0.0.1 pma 
---TRANSACTION 64003, not started
MySQL thread id 1, OS thread handle 0x143c, query id 0 Reading from net
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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
1988 OS file reads, 4586 OS file writes, 2359 OS fsyncs
0.05 reads/s, 16384 avg bytes/read, 0.27 writes/s, 0.23 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
0.66 hash searches/s, 1.61 non-hash searches/s
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LOG
---
Log sequence number 6091768
Log flushed up to   6091768
Pages flushed up to 6091768
Last checkpoint at  6091768
Max checkpoint age    7782360
Checkpoint age target 7539162
Modified age          0
Checkpoint age        0
0 pending log writes, 0 pending chkp writes
1064 log i/o's done, 0.09 log i/o's/second
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BUFFER POOL AND MEMORY
----------------------
Total memory allocated 17481728; in additional pool allocated 0
Total memory allocated by read views 1584
Internal hash tables (constant factor + variable factor)
    Adaptive hash index 297776 	(277192 + 20584)
    Page hash           18136 (buffer pool 0 only)
    Dictionary cache    161312 	(70736 + 90576)
    File system         834000 	(812272 + 21728)
    Lock system         43456 	(42376 + 1080)
    Recovery system     0 	(0 + 0)
Dictionary memory allocated 90576
Buffer pool size        1023
Buffer pool size, bytes 16760832
Free buffers            766
Database pages          256
Old database pages      0
Modified db pages       0
Percent of dirty pages(LRU & free pages): 0.000
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 1925, created 3, written 2994
0.05 reads/s, 0.00 creates/s, 0.14 writes/s
Buffer pool hit rate 993 / 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[8]: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 1640, state: sleeping
Number of rows inserted 0, updated 707, deleted 0, read 4097
0.00 inserts/s, 0.05 updates/s, 0.00 deletes/s, 0.73 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 19
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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