My application creates multiple (6-7) connections to the server. After about 5 minutes, 1 of the connections will be dropped. I can't really figure out why. Other than the aurora_fwd_master_idle_timeout that is set to 60, other configs remain at their default values. wait_timeout value, for example, defaults at 8 hours, so it should be long enough.
If I limit the multiple connections to 3-4, sometimes it work, sometimes it doesn't.
When it doesn't work, the detailed error is as follows:
MySql.Data.MySqlClient.MySqlException (0x80004005): Fatal error encountered during data read.
---> MySql.Data.MySqlClient.MySqlException (0x80004005): Reading from the stream has failed.
---> System.IO.IOException: The read operation failed, see inner exception.
---> System.TimeoutException: Unable to read data from the transport connection: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
---> System.IO.IOException: Unable to read data from the transport connection: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
Any ideas of what could possibly cause this?
Related
MySQL 5.7, a transaction is running but thread is sleeping, client request(tomcat) is blocking, it will last for many many seconds, after killing connection in MySQL, tomcat receives below exception:
org.springframework.dao.RecoverableDataAccessException:
### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 852,932 milliseconds ago. The last packet sent successfully to the server was 857,937 milliseconds ago.
at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:98)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:73)
at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:82)
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:446)
at com.sun.proxy.$Proxy59.selectList(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:230)
......
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:989)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2222)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:1982)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:3407)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:470)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:3109)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:2334)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2733)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1192)
......
Caused by: java.io.EOFException: Can not read response from server. Expected to read 20,481 bytes, read 19,682 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3008)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2205)
I use alibaba druid Connection Pool, testOnBorrow=true, mysql java driver version is 5.1.40
The above exception is thrown after connection is killed, tomcat is blocking until the connection is killed.
This case occurs several times in production evn, it is hard to repeat in develop env.
As the caused exception is Can not read response from server. Expected to read 20,481 bytes, read 19,682 bytes before connection was unexpectedly lost., client is waiting for more data from server, so I guess the connection borrowed from pool is valid at first, but why can't reading more data from server?
BTW: we recently use MySQL /*+ MAX_EXECUTION_TIME(xxx) */ optimizer hint. MySQL will throw Exception if query is timeout, I don't know whether it is related with my problem, but I guess it should not.
Presumably your query from your servlet ran for longer than your MAX_EXECUTION_TIME. At any rate, it looks like your query timed out when it had been running for 853 seconds.
And, your servlet crashed. The error trace you provided shows what happened.
If you want your servlet to recover from having its JDBC connections killed, you must program it to catch an exception when you KILL its database process, and then repeat the query.
You'll have to do some experimenting to get this right.
You can force the failure in development by using a much shorter MAX_EXECUTION_TIME. Or you can access your development MySQL server with a command client, look up the processid of the process serving your spring servlet, and KILL it manually.
The root cause: I believe your query takes far too long. You must optimize it somehow. Look at query-performance for ideas about that.
I have fired below Select Statement and I got this error. Any one help me.
select top 100
MenuID, MenuGroup, MenuName, ObjectName, ObjectTitle
from tblMenuMaster
where
ApplicationID = 3
and recStatus = 'A'
Error Message.
A transport-level error has occurred when receiving results from the
server. (provider: TCP Provider, error: 0 - The semaphore timeout
period has expired.)
Already apply Non Clustered Index on tblMenuMaster (MenuGroup,MenuName,ObjectName,ObjectTitle).
Its one of the random error which comes on SQL Server. If you reboot your machine and then try to execute the query, mostly it will not come.
You can check this MSDN blogs to get the details however.
Removing Connections
The connection pooler removes a connection from the pool after it has
been idle for a long time, or if the pooler detects that the
connection with the server has been severed.
Note that a severed connection can be detected only after attempting
to communicate with the server. If a connection is found that is no
longer connected to the server, it is marked as invalid.
Invalid connections are removed from the connection pool only when
they are closed or reclaimed.
If a connection exists to a server that has disappeared, this
connection can be drawn from the pool even if the connection pooler
has not detected the severed connection and marked it as invalid.
This is the case because the overhead of checking that the connection
is still valid would eliminate the benefits of having a pooler by
causing another round trip to the server to occur.
When this occurs, the first attempt to use the connection will detect
that the connection has been severed, and an exception is thrown.
I think the sever connection must be terminated due to which the error occurs. You need to reconnect the server and again fire the query.
However if this occurs on a frequent basis you need to get in touch with your DBA.
I have meet one issue:
There is one database,it could be connected by sqldeveloper tools
But I want to use c3p0 to connect the database with the jdbcurl:
jdbc:oracle:thin:#2.2.6.11:2709:hl.webtest.com
get these error:
WARN - com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask#55854763 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (5). Last acquisition attempt exception:
java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor
at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
why C3p0 throw the error? It seemed that the jdbcurl is wrong, what is correct jdbcurl with the Service Name?
jdbc:oracle:thin:#//2.2.6.11:2709/hl.webtest.com
it is use service_name, not the SID
You need the // and the /
I have Mysql DB connected to .NET MVC. When i connect remote it some times works fine and some times i have this error msg:
MySql.Data.MySqlClient.MySqlException (0x80004005): Authentication to
host 'ServerName' for user 'UserName' using method
'mysql_native_password' failed with message: Reading from the stream
has failed. ---> MySql.Data.MySqlClient.MySqlException (0x80004005):
Reading from the stream has failed. ---> System.IO.IOException: Unable
to read data from the transport connection: An established connection
was aborted by the software in your host machine. --->
System.Net.Sockets.SocketException: An established connection was
aborted by the
Please how can i make Authentication ? Any ideas to solve it?
This is a common error when some kind of deadlock occurs on the database more commonly a connection has been open a long time and gets shut down at the database end even though it is still in-use in your web application.
In my code, I used a suggestion from Microsoft, that retries the database command if it fails. The link is here: http://social.technet.microsoft.com/wiki/contents/articles/4235.retry-logic-for-transient-failures-in-windows-azure-sql-database.aspx Similar things exist for other non-Azure problems that use RetryPolicy.
What this means in a simple (Azure in my case) example is:
private static RetryPolicy<SqlAzureTransientErrorDetectionStrategy> retryPolicy = new RetryPolicy<SqlAzureTransientErrorDetectionStrategy>(new Incremental(3, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1)));
// Inside your database function
retryPolicy.ExecuteAction(() =>
{
db.ExecuteStoredProc("procRecordMetric", cmd);
});
In my case, this was caused by ssl being enabled on the mysql server.
Here is a snippet from my.cnf
#ssl-ca = /etc/ssl/mysql/ca-cert.pem
#ssl-cert = /etc/ssl/mysql/server-cert.pem
#ssl-key = /etc/ssl/mysql/server-key.pem
Commenting these 3 lines fixed the issue for me.
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We have a clan MySQL database that tracks player stats in a game. There person in charge of our MySQL is away at the moment and we are getting this following Error
[18:17:18 23] Error in Tablebuilder:
[18:17:18 23] Message: Unable to connect to any of the specified MySQL hosts.
[18:17:18 23] Native: -2147467259
[18:17:18 24] Source: MySql.Data
[18:17:18 24] StackTrace: at MySql.Data.MySqlClient.NativeDriver.Open()
at MySql.Data.MySqlClient.Driver.Open()
at MySql.Data.MySqlClient.Driver.Create(MySqlConnecti onStringBuilder settings)
at MySql.Data.MySqlClient.MySqlPool.GetPooledConnecti on()
at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
at MySql.Data.MySqlClient.MySqlPool.GetConnection()
at MySql.Data.MySqlClient.MySqlConnection.Open()
at PRoConEvents.CChatGUIDStatsLoggerBF3.tablebuilder( )
[18:17:18 24] InnerException: System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 50.63.244.184:3306
at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
at MySql.Data.Common.StreamCreator.CreateSocketStream (IPAddress ip, Boolean unix)
at MySql.Data.Common.StreamCreator.GetStreamFromHost( String pipeName, String hostName, UInt32 timeout)
at MySql.Data.Common.StreamCreator.GetStream(UInt32 timeout)
at MySql.Data.MySqlClient.NativeDriver.Open()
[18:17:18 24] Error: System.NullReferenceException: Object reference not set to an instance of an object.
at PRoConEvents.CChatGUIDStatsLoggerBF3.tablebuilder( )
Any ideas what the issue could be?
You should start by reading error messages. They look like gibberish but when you read closely, often there is a part it tells you what's going on.
[18:17:18 24] InnerException: System.Net.Sockets.SocketException:
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 50.63.244.184:3306
You should now:
Execute telnet localhost 3306 from the database server and if it fails, it's an issue with the DB server
Execute telnet 50.63.244.184 3306 from the application server and if it fails, it's an issue with the network
You have two exceptions, them tested, but the meaning is clear:
"Unable to connect to any of the specified MySQL hosts."
and
"A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond"
So in short: your webserver cannot connect to you database server. Your database server (the MySQL server process mysqld.exe or the server itself, like its OS, hardware, anything) might be stopped. Or the firewall was reset to block connections on the MySQL port 3306. It could be anything.
I assume you've got a standard webhost - ping them and ask them why your database server isn't operational.
...but before you embarrass yourself, make sure that your application is connecting to the right server (i.e. production DB, not dev or staging DB). Take a look at your connection string.