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Xtradb 5.5.34 cluster is hung with semaphores for 30 mins

mandmmandm ContributorInactive User Role Beginner
I had an issue with my 3 node cluster this morning
and when i checked the processlist, it was about 300 processes and the load average on the server was about 20

show engine innodb status was

mysql> show engine innodb status\G;
*************************** 1. row ***************************
Type: InnoDB
Name:
Status:
=====================================
140530 11:56:18 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 35 seconds
BACKGROUND THREAD
srv_master_thread loops: 213 1_second, 212 sleeps, 21 10_second, 1 background, 1 flush
srv_master_thread log flush and writes: 216
SEMAPHORES
OS WAIT ARRAY INFO: reservation count 396335, signal count 65288
--Thread 140005560661760 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005551077120 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140004927194880 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005555869440 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005555603200 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005543622400 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140004927993600 has waited at row0sel.c line 3670 for 0.0000 seconds the semaphore:
S-lock on RW-latch at 0x6653a48 '&btr_search_latch_arr'
number of readers 0, waiters flag 0, lock_word: 100000
Last time read locked in file row0sel.c line 3670
Last time write locked in file /mnt/workspace/percona-xtradb-cluster-debs/label_exp/ubuntu-precise-64bit/target/Percona-XtraDB-Cluster-5.5.34/storage/innobase/btr/btr0sea.c line 674
--Thread 140005536966400 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005551875840 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0
--Thread 140005535368960 has waited at row0sel.c line 3670 for 0.0000 seconds the semaphore:
S-lock on RW-latch at 0x6653a48 '&btr_search_latch_arr'
number of readers 0, waiters flag 0, lock_word: 100000
Last time read locked in file row0sel.c line 3670
Last time write locked in file /mnt/workspace/percona-xtradb-cluster-debs/label_exp/ubuntu-precise-64bit/target/Percona-XtraDB-Cluster-5.5.34/storage/innobase/btr/btr0sea.c line 674
--Thread 140005536700160 has waited at row0sel.c line 3670 for 0.0000 seconds the semaphore:
S-lock on RW-latch at 0x6653a48 '&btr_search_latch_arr'
number of readers 0, waiters flag 0, lock_word: 100000
Last time read locked in file row0sel.c line 3670
Last time write locked in file /mnt/workspace/percona-xtradb-cluster-debs/label_exp/ubuntu-precise-64bit/target/Percona-XtraDB-Cluster-5.5.34/storage/innobase/btr/btr0sea.c line 674
--Thread 140005559064320 has waited at buf0buf.ic line 376 for 0.0000 seconds the semaphore:
Mutex at 0x7f55a3f645f0 '&block->mutex', lock var 0
waiters flag 0

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, 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
78491 OS file reads, 13057 OS file writes, 10571 OS fsyncs
0.49 reads/s, 16384 avg bytes/read, 48.17 writes/s, 24.26 fsyncs/s
INSERT BUFFER AND ADAPTIVE HASH INDEX
Ibuf: size 1, free list len 29, seg size 31, 202 merges
merged operations:
insert 1312, delete mark 19, delete 14
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 4425293, node heap has 33 buffer(s)
451242.08 hash searches/s, 224663.50 non-hash searches/s
---
LOG
---
Log sequence number 147447557967
Log flushed up to 147447557686
Last checkpoint at 147447475545
Max checkpoint age 108005254
Checkpoint age target 104630090
Modified age 82422
Checkpoint age 82422
0 pending log writes, 0 pending chkp writes
10361 log i/o's done, 22.34 log i/o's/second
BUFFER POOL AND MEMORY
Total memory allocated 2204106752; in additional pool allocated 0
Total memory allocated by read views 31912
Internal hash tables (constant factor + variable factor)
Adaptive hash index 35947232 (35402344 + 544888)
Page hash 2213656 (buffer pool 0 only)
Dictionary cache 9282508 (8851984 + 430524)
File system 214000 (82672 + 131328)
Lock system 5339736 (5313416 + 26320)
Recovery system 0 (0 + 0)
Dictionary memory allocated 430524
Buffer pool size 131071
Buffer pool size, bytes 2147467264
Free buffers 52526
Database pages 78512
Old database pages 29001
Modified db pages 113
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 13, not young 0
0.03 youngs/s, 0.00 non-youngs/s
Pages read 78427, created 85, written 2630
0.46 reads/s, 0.20 creates/s, 25.26 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: 78512, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
ROW OPERATIONS
0 queries inside InnoDB, 0 queries in queue
66 read views open inside InnoDB
65 transactions active inside InnoDB
65 out of 1000 descriptors used
---OLDEST VIEW---
Normal read view
Read view low limit trx n:o 2747ABC
Read view up limit trx id 2747ABB
Read view low limit trx id 2747ABC
Read view individually stored trx ids:
Read view trx id 2747ABB
Main thread process no. 11805, id 140005579044608, state: flushing log
Number of rows inserted 4641, updated 886, deleted 72, read 96396503
10.06 inserts/s, 2.03 updates/s, 0.09 deletes/s, 450948.66 reads/s

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