I have relatively large table with 7,517,717 records in my Azure SQL DB (which is on Azure V12 server, and it is on P4 pricing tier).
When I created table I forgot to define the MaxLength for a property, so now it is of type nvarchar(max).
I wanted to change this so I created migration (using FluentAPI) which looks like this:
public partial class FeedTitleMaxLength : DbMigration
{
public override void Up()
{
AlterColumn("dbo.Feed", "Title", c => c.String(maxLength: 100));
}
public override void Down()
{
AlterColumn("dbo.Feed", "Title", c => c.String());
}
}
I've run Update-Database command like this:
Update-Database -Verbose -ConnectionString "Data Source=serverUrl,1433;Database=dbName;User ID=myusername;Password=mypassword;Trusted_Connection=False;Encrypt=True;Connection Timeout=3000;MultipleActiveResultSets=True;" -ConnectionProviderName "System.Data.SqlClient"
My connection string in web.config looks the same. And I've also defined timeout like this:
this.Database.CommandTimeout = 3000;
But no matter what I do or try I get this error after 30/40 seconds:
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. This failure occurred while attempting to connect to the routing destination. The duration spent while attempting to connect to the original server was - [Pre-Login] initialization=97; handshake=110; [Login] initialization=0; authentication=0; [Post-Login] complete=32;
Is there any way I can run this migration? Or some workaround? Can I, for example, create migration but run the AlterColumn command in SQL and then Update-Database command. Would this mess things or not?
Related
We have a .Net Core API accessing Azure SQL (Gen5, 4 vCores)
Since quite some time,
the API keeps throwing below exception for a specific READ operation
Microsoft.Data.SqlClient.SqlException (0x80131904): Execution Timeout
Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
The READ operation has code to read rows of data and convert an XML column into a specific output format.
Most of the read operation extracts hardly 4-5 rows # a time.
The tables involved in the query have ~ 500,000 rows
We are clueless on Root Cause of this issue.
Any hints on where to start looking # for root cause?
Any pointer would be highly appreciated.
NOTE : Connection string has following settings, apart from others
MultipleActiveResultSets=True;Connection Timeout=60
Overall code looks something like this.
HINT: The above timeout exception comes # ConvertHistory, when the 2nd table is being read.
HttpGet]
public async Task<IEnumerable<SalesOrders>> GetNewSalesOrders()
{
var SalesOrders = await _db.SalesOrders.Where(o => o.IsImported == false).OrderBy(o => o.ID).ToListAsync();
var orders = new List<SalesOrder>();
foreach (var so in SalesOrders)
{
var order = ConvertSalesOrder(so);
orders.Add(order);
}
return orders;
}
private SalesOrder ConvertSalesOrder(SalesOrder o)
{
var newOrder = new SalesOrder();
var oXml = o.XMLContent.LoadFromXMLString<SalesOrder>();
...
newOrder.BusinessUnit = oXml.BusinessUnit;
var history = ConvertHistory(o.ID);
newOrder.history = history;
return newOrder;
}
private SalesOrderHistory[] ConvertHistory(string id)
{
var history = _db.OrderHistory.Where(o => o.ID == id);
...
}
Microsoft.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
From Microsoft Document,
You will get this error in both conditions Connection timeout or Query or command timeout. first identify it from call stack of the error messages.
If you found it as a connection issue you can either Increase connection timeout parameter. if you are still getting same error, it is causing due to a network issue.
from information that you provided It is Query or command timeout error to work around this error you can set CommandTimeout for query or command
command.CommandTimeout = 10;
The default timeout value is 30 seconds, the query will continue to run until it is finished if the time-out value is set to 0 (no time limit).
For more information refer Troubleshoot query time-out errors provided by Microsoft.
Description:
I have an application that connects to an Azure Serverless Database. The database can be in a paused state and in an online state. The database auto-pauses when there has been no activity for one hour. This means that when my application tries to open a connection to the database when it is paused, the connection times out and gives a timeout exception.
Azure states in their documentation that:
If a serverless database is paused, then the first login will resume the database and return an error stating that the database is unavailable with error code 40613. Once the database is resumed, the login must be retried to establish connectivity. Database clients with connection retry logic should not need to be modified. source
I am able to get this error code 40613 returned when I try to connect to the database via SQL Management Studio. But when I try to open a connection to the database from my application I only get a timeout exception, hence I don't know whether or not the database is not available or if the database is in fact resuming.
Code example:
public IDbConnection GetConnection()
{
var connection = new SqlConnection(_connectionString);
try
{
connection.Open();
return connection;
}
catch (SqlException e)
{
if (e.Number == 40613)
{
//Database is resuming
}
}
finally
{
connection.Close();
}
}
Exception example:
When I run my application and the database is in paused state I get this exception:
Snippet of exception in Visual Studio
Does anyone know why I don't get the error code 40613 that Azure states in their documentation?
Indeed you may get timeout errors when the Azure database is unavailable. In fact you may get the following errors:
HTTP error GatewayTimeout : The gateway did not receive a response
from ‘Microsoft.Sql’ within the specified time period
HTTP error ServiceUnavailable : The request timed out
SQLException : Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
You may get also error 40613 but you can capture some transient errors like below too:
•Database on server is not currently available. Please retry the connection later. If the problem persists, contact customer support, and provide them the session tracing ID of
•Database on server is not currently available. Please retry the connection later. If the problem persists, contact customer support, and provide them the session tracing ID of . (Microsoft SQL Server, Error: 40613)
•An existing connection was forcibly closed by the remote host.
•System.Data.Entity.Core.EntityCommandExecutionException: An error occurred while executing the command definition. See the inner exception for details. ---> System.Data.SqlClient.SqlException: A transport-level error has occurred when receiving results from the server. (provider: Session Provider, error: 19 - Physical connection is not usable)
•An connection attempt to a secondary database failed because the database is in the process of reconfguration and it is busy applying new pages while in the middle of an active transation on the primary database.
Because of those errors and more explained here, it is necessary to create a retry logic on applications that connect to Azure SQL Database.
public void HandleTransients()
{
var connStr = "some database";
var _policy = RetryPolicy.Create < SqlAzureTransientErrorDetectionStrategy(
retryCount: 3,
retryInterval: TimeSpan.FromSeconds(5));
using (var conn = new ReliableSqlConnection(connStr, _policy))
{
// Do SQL stuff here.
}
}
More about how to create a retry logic here.
The application that im working on runs a sequence of queries on AWS Redshift. Some of the queries take longer to execute due to the data volume.
The queries seem to finish on Redshift when i check the execution details on the server. However, the java application seems to hang indefinitely without throwing any exception or even terminating.
Here's the code that executes the query.
private void execSQLStrings(String[] queries, String dataset, String dbType) throws Exception {
Connection conn = null;
if (dbType.equals("redshift")) {
conn=getRedshiftConnection();
} else if (dbType.equals("rds")){
conn=getMySQLConnection();
}
Statement stmt=conn.createStatement();
String qry=null;
debug("Query Length: " + queries.length);
for (int ii=0;ii<queries.length;++ii) {
qry=queries[ii];
if (dataset != null) {
qry=qry.replaceAll("DATASET",dataset);
}
debug(qry);
stmt.execute(qry);
}
stmt.close();
conn.close();
}
I cant post the query that im running at the moment but it has multiple table joins and group by conditions and its an 800m row table. The query takes about 7~8 mins to complete on the server.
You need to update the DSN Timeout and/ or KeepAlive settings to make sure that your connections stay alive.
Refer: http://docs.aws.amazon.com/redshift/latest/mgmt/connecting-firewall-guidance.html
I have a WCF service that has some operations that may take long...
The client receives a TimeoutException, but the server continues executing after the long operation.
Server:
public void doSomeWork(TransmissionObject o) {
doDBOperation1(o); //
doDBOperation2(o); // may result in TimeoutException on client
doDBOperation3(o); // it continues doing DB operations. The client is unaware!
}
Client:
ServiceReference.IServiceClient cli = new ServiceReference.IServiceClient("WSHttpBinding_IService","http://localhost:3237/Test/service.svc");
int size = 1000;
Boolean done = false;
TransmissionObject o = null;
while(!done) {
o = createTransmissionObject(size);
try {
cli.doSomeWork(o);
done = true;
}catch(TimeoutException ex) {
// We want to reduce the size of the object, and try again
size--;
// the DB operations in server succeed, but the client doesn't know
// this makes errors.
}catch(Exception ex) { ... }
}
Since the server is performing some DB operations, I need to detect the timeout on the server side to be able to rollback the DB operations.
I tried to use Transactions with [TransactionFlow], TransactionScope, etc, on the client side, but the DB operations on the server are using Stored Procedures that are NESTED!!, therefore I cannot use distributed transactions. (I receive an SqlException saying: Cannot Use SAVE TRANSACTION Within A Distributed Transaction.). If I use simple SPs (that are not nested), then the solution with the transactions works fine.
My Question:
How can I detect the TimeoutException, but on the server side? I guess is something related to the proxy status... or probably some Events that can be captured by the server.
I'm not sure if handling the transaction on the server side is the correct solution..
Is there a pattern to solve this problem?
Thanks!
Instead of waiting for an operation to time out, you may consider using asynchronous operations, as in this blog post: http://www.danrigsby.com/blog/index.php/2008/03/18/async-operations-in-wcf-event-based-model/
The idea is that you precisely expect an operation to take some time. The server will signal to the client when the job is finished.
please help me resolve this problem:
There is an ambient MSMQ transaction. I'm trying to use new transaction for logging, but get next error while attempt to submit changes - "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding." Here is code:
public static void SaveTransaction(InfoToLog info)
{
using (TransactionScope scope =
new TransactionScope(TransactionScopeOption.RequiresNew))
{
using (TransactionLogDataContext transactionDC =
new TransactionLogDataContext())
{
transactionDC.MyInfo.InsertOnSubmit(info);
transactionDC.SubmitChanges();
}
scope.Complete();
}
}
Please help me.
Thx.
You could consider increasing the timeout or eliminating it all together.
Something like:
using(TransactionLogDataContext transactionDC = new TransactionLogDataContext())
{
transactionDC.CommandTimeout = 0; // No timeout.
}
Be careful
You said:
thank you. but this solution makes new question - if transaction scope was changed why submit operation becomes so time consuming? Database and application are on the same machine
That is because you are creating new DataContext right there:
TransactionLogDataContext transactionDC = new TransactionLogDataContext())
With new data context ADO.NET opens up new connection (even if connection strings are the same, unless you do some clever connection pooling).
Within transaction context when you try to work with more than 1 connection instances (which you just did)
ADO.NET automatically promotes transaction to a distributed transaction and will try to enlist it into MSDTC. Enlisting very first transaction per connection into MSDTC will take time (for me it takes 30+ seconds), consecutive transactions will be fast, however (in my case 60ms). Take a look at this http://support.microsoft.com/Default.aspx?id=922430
What you can do is reuse transaction and connection string (if possible) when you create new DataContext.
TransactionLogDataContext tempDataContext =
new TransactionLogDataContext(ExistingDataContext.Transaction.Connection);
tempDataContext.Transaction = ExistingDataContext.Transaction;
Where ExistingDataContext is the one which started ambient transaction.
Or attemp to speed up your MS DTC.
Also do use SQL Profiler suggested by billb and look for SessionId between different commands (save and savelog in your case). If SessionId changes, you are in fact using 2 different connections and in that case will have to reuse transaction (if you don't want it to be promoted to MS DTC).