Lost connection to MySQL server at 'waiting for initial communication packet' - mysql

Question

I have seen many stack overflows questions and some blogs tried workarounds, but nothings helped - hence re-posting the question with more details.
I am seeing the weird behaviour with MySQL and Python application, details are as follows:
1) My application works perfectly fine with MySQL (tried and tested on many platforms) but on this particular machine it fails to connect to MySQL.
structure of application is :
Windows service -> parent process -> Mysql(child process)
and when application tries to connect to MySQL it get this error:
ERROR 2013 , Lost connection to MySQL server at 'waiting for initial communication packet' - system error 0
I tried:
- connect_timeout=300
- skip-name-resolve=0
- firewall is OFF
- use 17.0.0.1, localhost , IP of machine to connect to but it still fails with same error.
2) Now the weird thing is -
If I manually follow all the steps which application does, It works perfectly fine, details are follows:
a) Start MySQL with same command (which application uses) with administrator privileges
mysql --default-file = xxx --basedir =xxx
b) Connect with same credentials ( -u root -P 6075 -h 127.0.0.1) and
It works perfectly fine, I double checked all the steps which application does, there is no difference between manually steps and application code.
AM I missing something here ? Any suggestions ?
MySQL version : 5.5.35
Python : 2.7
Base OS : Windows 2012 R2
Thanks in advance..

Answer 1

Found a reason - answering my question:
When I used to run MySQL from my application - it was running under system user privileges - so it used to pick "C:\WINDOWS\TEMP" as a temp directory- this directory was messed up - has lot of unnecessary files .. and MySQL was stuck while processing files under this directory...
But when I ran it manually under My administrator account it was using his temp directory... C:\Users\USER_NAME\AppData\Local\Temp and everything was working like magic...
To fix this permanently I changed tmp directory through MySQL conf file and now My Application runs like the Wind.... :)
[mysqld]
tmpdir = 'PATH_TO_THE_DIRECTORY'

Answer 2

I was getting this same error trying to set up a SQL Server Linked Server
Cannot initialize the data source object of OLE DB provider "MSDASQL" for linked server "DBLINKED".
OLE DB provider "MSDASQL" for linked server "DBLINKED" returned message "[MySQL][ODBC 8.0(w) Driver]Lost connection to MySQL server at 'waiting for initial communication packet', system error: 10060". (Microsoft SQL Server, Error: 7303)
You mentioned it in your initial question - the Connection Timeout was the issue for me.
The default is 0 - raised it to 300. I thought default of 0 would mean no timeout, but it's obviously something reasonably short, and I was trying to connect to a remote database on a slow internet connection. A lot of other question and answers out there relate to connecting within the same machine, so this error isn't reported much.