MySQL Bugs: #89100: Copy server-client failed A non-blocking socket operation could no be completed

Bug #89100	Copy server-client failed A non-blocking socket operation could no be completed
Submitted:	4 Jan 2018 1:22	Modified:	2 Apr 2018 12:52
Reporter:	Saverio Loiacono	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Router	Severity:	S2 (Serious)
Version:	2.1.4	OS:	Windows (2016)
Assigned to:	MySQL Verification Team	CPU Architecture:	Any

Description:
I have an error using MySQL Server Routing, below my environment:
One Web Server with:
	- Windows 2016
	- IIS 10
	- WordPress 4.8.3
	- PHP 7.1.11
	- MySQL Router 2.1.4 

Three DB Server with a MySQL instance for each server and InnoDB Cluster. One instance is R/W the other two are R/O:
	- Windows 2016
	- MySQL CE 5.7.20

When i configure the FrontEnd server to use MySQL Router 2.1.4 i, often receive the error below:

From PHP error log:
	php[6036]
	PHP Warning:  mysqli_query(): Error reading result set's header in ....\wp-includes\wp-db.php on line 1942
	php[6036]
	PHP Warning:  mysqli_query(): MySQL server has gone away in ....\wp-includes\wp-db.php on line 1942
	php[6036]
	PHP Warning:  mysqli_query(): (00000/0):  in ....\wp-includes\wp-db.php on line 1942
	php[6036]
	PHP Warning:  Empty row packet body in ....\wp-includes\wp-db.php on line 1942

From mysqlrouter.log:
	DEBUG   [f08] Write error: SystemError: A non-blocking socket operation could not be completed immediately.
	DEBUG   [954] Write error: SystemError: A non-blocking socket operation could not be completed immediately.
	DEBUG   [f08] [routing:MySQLCLU_default_rw] Routing stopped (up:376143b;down:385b) Copy server-client failed: SystemError: A non-blocking socket operation could not be completed immediately.
	DEBUG   [954] [routing:MySQLCLU_default_rw] Routing stopped (up:384175b;down:385b) Copy server-client failed: SystemError: A non-blocking socket operation could not be completed immediately.

From MySQL Server.err
	[Note] Aborted connection 2140 to db: 'xxxxxxxx' user: 'xxxxxxxx' host: 'xxxxxxxx' (Got an error writing communication packets)
	[Note] Aborted connection 2141 to db: 'xxxxxxxx' user: 'xxxxxxxx' host: 'xxxxxxxx' (Got an error writing communication packets)

If i configure the FrontEnd server to use directly the r/w MySQL instance all work correctly.

How i can solve the problem ?

How to repeat:
The problem can be reproduced with a simple php page with a query. I use a table with two columns:
- varchar
- longtext
and 500 rows. The table size is about 1.5MB

Hi,

I can't reproduce this but it looks a lot like bug #88108.

Do you have a problem *every time* you try to read a big table with big result set? What are your configs for mysql's and router?

Is this running on bare metal or you are running it inside some vm's? Azure by any chance?

thanks
Bogdan

Configuratio File My SQL Server 1

Attachment: my-testdb01.ini (application/octet-stream, text), 13.94 KiB.

Configuratio File My SQL Server 2

Attachment: my-testdb02.ini (application/octet-stream, text), 13.93 KiB.

Configuratio File My SQL Server 3

Attachment: my-testdb03.ini (application/octet-stream, text), 13.93 KiB.

Configuratio File My SQL Router

Attachment: mysqlrouter.conf (application/octet-stream, text), 1.28 KiB.

Hi Bogdan, I'm sorry for the delay, the error occurs randomly. I'm running MySQL Serer e My SQL Router in a VM on Openstack Cloud platform. I attach 
the configuration files.

Regards
Saverio

Hi,

Thanks for the update, I'll try running this on my vm's today to see if I can reproduce it so we'll see.

all best
Bogdan

Hi Bogdan, i installed My SQL Router 2.1.6 and the problem no longer occurred.

Thanks
Saverio

Hi,
Thanks for the update, so the bug is solved already :)
all best
Bogdan