mysqli over ssl giving 2003 - php

Question

I'm using mysqli connection over ssl,
so using in code following:
$mdbconnection = mysqli_init();
$mdbconnection->ssl_set('/ssl/xyz.pem', '/ssl/abc-cert.pem', NULL, NULL, 'AES256-SHA');
$mdbconnection->real_connect(SV_SERVER, SV_MYSQL_LOGIN, SV_MYSQL_PASSWORD, SV_MYSQL_DATABASE);
I noted down that I am not able to connect over mysql server all the time.
if trying 100 times failing 3 time.
and getting following error
echo($mdbconnection->connect_errno);
printing:
2003
and if I am trying second time after failing it{echo($mdbconnection->connect_errno);} will give always 1045.
I am trying to solve this bug.
Any ideas would be appreciated.

Answer 1

The 2003 error code means the connection couldn't be established:
https://dev.mysql.com/doc/refman/5.5/en/error-messages-client.html
Error code 1045 means the client connected but the server rejected the credentials (access denied):
https://dev.mysql.com/doc/refman/5.5/en/error-messages-server.html
I'd say that if you're getting the 2003 error code a few times out of every 100 tries, it sounds like some of the possibilities could be:
Some intermediate application or piece of hardware might be seeing your attempts as a possible flood attack (DDoS) and could be intercepting and blocking the connection (if you're connecting 100 times really quickly)
You might have some network stability issues on the client side. It might be worth the time to run Wireshark and reproduce the problem with it running in order to capture the problem and see if it shows anything significant (e.g. DNS failure).
The MySQL server might be crashing and then restarting. Check your server-side MySQL error log (https://dev.mysql.com/doc/refman/5.7/en/error-log.html). Actually, you should really do this as a first step any time you have bizarre behavior in MySQL.
If the MySQL server log doesn't show anything, check your system logs, especially if you're logging anything like blocked firewall (iptables or whatever f/w you're using) packets and search them for your client IP around the time of the problem.
Finally, if you can reproduce this easily/quickly (e.g. make 100 connections via a script and see it fail), try eliminating SSL out of the equation and connecting without SSL and see if it gives you the same problem. If it works flawlessly without SSL, perhaps there's a problem with the SSL library that was used during the compilation of your MySQL package.
You might also want to check to see if you have any load-balancing in place that might make your script connect to different instances of the MySQL server (this is less likely, but could explain the symptoms you're seeing if one server is down and the next doesn't have the credentials you're providing)