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I managed to create a mysql InnoDB cluster with three nodes and a router everything works great but when i try to run a select query from the table below from a another server it freezes, but it works when i limit the result to a number under 26
SET NAMES utf8;
SET time_zone = '+00:00';
SET NAMES utf8mb4;
DROP TABLE IF EXISTS `v7_addad`;
CREATE TABLE `v7_addad` (
`id` int NOT NULL AUTO_INCREMENT,
`body` text CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
`page_id` int NOT NULL,
`done` tinyint NOT NULL DEFAULT '0',
`book` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
PRIMARY KEY (`id`),
FULLTEXT KEY `body` (`body`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
For example :
select * from v7_addad limit 25; # this works
select * from v7_addad limit 26; # this freezes
BTW if doesn't freeze when trying from the R/W node (the server hosting the main mode).
show engine innodb status;
=====================================
2021-01-02 15:49:26 0x7f8584324700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 11 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 35520 srv_active, 0 srv_shutdown, 135529 srv_idle
srv_master_thread log flush and writes: 0
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 398
OS WAIT ARRAY INFO: signal count 589
RW-shared spins 269, rounds 269, OS waits 0
RW-excl spins 145, rounds 4321, OS waits 134
RW-sx spins 1, rounds 1, OS waits 0
Spin rounds per wait: 1.00 RW-shared, 29.80 RW-excl, 1.00 RW-sx
------------
TRANSACTIONS
------------
Trx id counter 207413
Purge done for trx's n:o < 207412 undo n:o < 0 state: running but idle
History list length 12
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 421696252934904, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252933192, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252934048, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252932336, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252931480, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252930624, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
---TRANSACTION 421696252929768, not started
0 lock struct(s), heap size 1136, 0 row lock(s)
--------
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] , aio writes: [0, 0, 0, 0] ,
ibuf aio reads:, log i/o's:, sync i/o's:
Pending flushes (fsync) log: 0; buffer pool: 18446744073709551589
5225 OS file reads, 765431 OS file writes, 599449 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 2.91 writes/s, 2.45 fsyncs/s
-------------------------------------
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
Hash table size 3984439, node heap has 2 buffer(s)
Hash table size 3984439, node heap has 1 buffer(s)
Hash table size 3984439, node heap has 1 buffer(s)
Hash table size 3984439, node heap has 2 buffer(s)
Hash table size 3984439, node heap has 1 buffer(s)
Hash table size 3984439, node heap has 3 buffer(s)
Hash table size 3984439, node heap has 4 buffer(s)
Hash table size 3984439, node heap has 7 buffer(s)
0.18 hash searches/s, 1.55 non-hash searches/s
---
LOG
---
Log sequence number 2237873266
Log buffer assigned up to 2237873266
Log buffer completed up to 2237873266
Log written up to 2237873266
Log flushed up to 2237873266
Added dirty pages up to 2237873266
Pages flushed up to 2237873266
Last checkpoint at 2237873266
247265 log i/o's done, 1.18 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 16483614720
Dictionary memory allocated 1956558
Buffer pool size 983040
Free buffers 977601
Database pages 5418
Old database pages 2027
Modified db pages 0
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 5153, created 265, written 361560
0.00 reads/s, 0.00 creates/s, 0.00 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: 5418, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
----------------------
INDIVIDUAL BUFFER POOL INFO
----------------------
---BUFFER POOL 0
Buffer pool size 491520
Free buffers 488755
Database pages 2754
Old database pages 1026
Modified db pages 0
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 2596, created 158, written 229420
0.00 reads/s, 0.00 creates/s, 0.00 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: 2754, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
---BUFFER POOL 1
Buffer pool size 491520
Free buffers 488846
Database pages 2664
Old database pages 1001
Modified db pages 0
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 2557, created 107, written 132140
0.00 reads/s, 0.00 creates/s, 0.00 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: 2664, 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
0 read views open inside InnoDB
Process ID=3803, Main thread ID=140203552966400 , state=sleeping
Number of rows inserted 0, updated 33674, deleted 0, read 5195822
0.00 inserts/s, 0.18 updates/s, 0.00 deletes/s, 15.91 reads/s
Number of system rows inserted 33706, updated 1120, deleted 33702, read 85994
0.18 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================
question from:
https://stackoverflow.com/questions/65540974/mysql-hangs-on-select-from-table-with-blob-fields 
