I am using mysql 5.5.16 on windows 2008 R2 virtual server, and remotely connecting to it using C# and locally connecting to it using PHP. Its been working fine for past 5 month but suddenly today I started getting this error in C# code:
Timeout expired: The timeout period elapsed prior to completion of the operation or the server is not responding.
Also if I use HeidiSQL, its also talking more than a minute to connect, however, once connected, the queries are running without any delay. I have tried adding skip_name_resolve in the server's my.ini file but no use.
Related
Hi When my Elastic Beanstalk (m5a.large Windows Server with deployed .net Core WebApi) comes under heavy load, the Status in the Health Page for my EC2 instances turns red, my Requests and the Healthcheck are timing out. That happens around 1-3 minutes after having a minimum of 10-20 Req/sec for a server.
I have to launch a lot of servers, so that each server gets a Request/Second count of 1-5 so they do not turn red.
In my logs I saw the following Errors:
Exception=MySql.Data.MySqlClient.MySqlException (0x80004005): Unable to connect to any of the specified MySQL hosts.
---> MySql.Data.MySqlClient.MySqlException (0x80004005): Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
These Errors brought me to the topic Connection Pooling so i switched
using MySql.Data.MySqlClient;
to
using MySqlConnector;
Now these Errors do not come up anymore but the Problem remains.
The Monitoring Feature of EB and RDS do not state any obvious Problems. Running Queries in Mysql Workbench against the Database is fast as usual.
At the moment, my Database calls from the server are synchronous and not using the async feature of MysqlConnector.
Does the m5a.large cannot process more than 5 Request/Second?
Kind Regards
I have aplications that connect to a remote server (MySQL 5.5 on Windows Server 2012), at first I started receiving "too many connections" message which I solved by increasing MAX_CONNECTION value in my.inf to 500, then I start getting "can't create new thread" message so I decrease decrease timeouts to avoid idle connections using a socket, which didn't completely work. Now I get odd messages like 'file not found', as soon as I restart the service I stop getting the messages and everything works correctly.
The problem occurs when the server reaches around 170 connections at the same time.
Is there some configuration I'm missing?, I really don't know what info you need to give me a hint to fix this. I mean, there are servers that accept a lot morw of connections at the same time, right? waht I'm missing.
RAM and CPU of the system dosen't reach 35-40% at max connections (170).
Edit: Error occur at 2 'places', when running a query or at the attempt of conennection, it's like the MySQL service rejects the attempt. VB6 is the language used in the client app (ODBC connector). The app opens, executes and closes the connection.
Note: I have full control over client app and server config.
We have one java application, which uses mysql db as back end.
Mysql 5.7.17 is installed on windows server 2012 R2 Standard
The issue is that our java application crashes mysql database,
We enabled logs and found out that there is this specific query that crashes mysql.
If I copy this query from the logs and run it in Workbench it crashes mysql and I get "Lost connection to mysql during query"
I tried increasing , max packet size, net read timeout to no avail.
To drill further , I installed same version mysql on another VM windows server 2012r2 standard , and here the query works fine, without any issues.
below is the query from the logs:
select userorgani0_.id as id1_16_,
userorgani0_.authority as authorit2_16_,
userorgani0_.organization_module_id as organiza3_16_,
userorgani0_.user_id as user_id4_16_
from user_organization_module userorgani0_
where userorgani0_.organization_module_id='2c9e85c75a4025ed015a402b72040004'
and userorgani0_.user_id='1rhdhdwi22c23214kcskcsk'
Could you please help me here.
regards,
RVS
I setup an old Django app on a new GCE instance on Sunday and pointed it to a new CloudSQL instance with imported data there. This code and data has successfully run over the past few years on a variety of dedicated hosting setups, on EC2 and on EC2+RDS.
Since Sunday I have had intermittent reports of 2013, "Lost connection to MySQL server at 'reading initial communication packet', system error: 0" from the App. In particular today it happened in two bursts of 3 separated by about 7 hours.
I panicked in the earlier outages and restarted both the app and the CloudSQL instance which did the trick. However the latter ones today righted themselves after a few minutes.
I've never encountered this error before working with MySQL and any searching on the error gives results related to people who have general access problems to the DB.
On the GCE side the only difference I can think of from previous setups is that it is using Google's out-of-the-box Debian image instead of Ubuntu 12.04. On the MySQL side I have no idea as I've successfully run this on both MySQL 5.x and MariaDB.
Is there any way of figuring out why this is happening and fixing it?
Thanks.
Have you tried changing keep alive settings for TCP connections? GCE has a firewall rules that drops idle TCP connections after 10 mins:
https://cloud.google.com/compute/docs/troubleshooting#communicatewithinternet
You can check current value of 'tcp_keepalive_time':
cat /proc/sys/net/ipv4/tcp_keepalive_time
And change it to 60 seconds:
vi /etc/sysctl.conf
# Add this line
net.ipv4.tcp_keepalive_time = 60
# Reload Sysctl interface
sudo /sbin/sysctl --load=/etc/sysctl.conf
You might need to restart Django server to pick new keep alive settings.
Note: If this problem was limited to yesterday (18/11/2014) and your Cloud SQL instances are located in EU, you might have been affected by this:
https://groups.google.com/forum/#!topic/google-cloud-sql-announce/k5raPT48hc0
It seems there is an issue with the firewall, preventing incoming connections, just change the location from the server to another mirror things suppose to go fine. It worked for me
We are having an intermittent issue with connections to our mysql server timing out.
The error we are receiving is as following.
(2003, 'Can\'t connect to MySQL server on \'<connection>\' ((2013, "Lost connection to MySQL server during query (error(104, \'Connection reset by peer\'))"))')
Callstack:
File "/usr/lib64/python2.7/site-packages/pymysql/connections.py", line 818, in _connect
2003, "Can't connect to MySQL server on %r (%s)" % (self.host, e))
File "/usr/lib64/python2.7/site-packages/pymysql/connections.py", line 626, in __init__
self._connect()
Some more info:
We have a flight of EC2 servers that are constantly running queries to a backend RDS.
We average about 500 connections per second to the RDS
We have around 0 - 4 hiccups per RDS per day
The hiccups don't correspond with our maintenance window
When we hit a hiccup it can affect quite a few connections ~50
When a hiccup happens it will disrupt connections across all servers and ports
The error itself looks to be generated from the tcp connection being closed on the ec2. Our TCP keep alive time is set to 7200 seconds and that's when the error is fired off.
My question is what can be done to track down why these hiccups happen? It's great that they don't happen often, but it's not ideal that they happen at all.
Any advice would be appreciated thanks!
Update 10/29:
I've been running a service checking to see if I have any long processes running on the sql server and it looks like these errors aren't getting that far. A new process is never created for this connection! I have still been receiving the hiccups, just no signs of connections.
So after a back and forth with amazon support here is the current solution we have come to.
Amazon has raised our socket listen backlog by adjusting the somaxconn value on the RDS instance.
The value was at the default of 128 and has been bumped up to 1024.
Once the value was adjusted we no longer received the Lost Connection error.