I am reading PDF files from Blob and doing some operation using Azure Function. When PDF size is 1.5GB(or greater) my azure function fails with out of memory exception as soon as it code hit below command.
var ms = new MemoryStream();
log.LogInformation("Converting this File to memorystream : " + blob.Uri);
blob.DownloadToStream(ms); //Failes HERE.
I tried increasing the plan switched to EP3 (14 GB Memory + 840 ACU). But problem is still same.
Do i need to change some other configuration as well? How this could be taken care.
Microsoft.Azure.Storage.StorageException: Exception of type 'System.OutOfMemoryException' was thrown.
---> System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
at System.IO.MemoryStream.set_Capacity(Int32 value)
at System.IO.MemoryStream.EnsureCapacity(Int32 value)
at System.IO.MemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.MemoryStream.WriteAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.Azure.Storage.Core.Util.AsyncStreamCopier`1.StartCopyStreamAsyncHelper(Nullable`1 copyLength, Nullable`1 maxLength, CancellationToken token)
at Microsoft.Azure.Storage.Core.Util.AsyncStreamCopier`1.StartCopyStreamAsync(Nullable`1 copyLength, Nullable`1 maxLength, CancellationToken cancellationToken)
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteAsync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token)
--- End of inner exception stack trace ---
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteAsync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token)
at Microsoft.Azure.Storage.Core.Executor.Executor.<>c__DisplayClass0_0`1.<ExecuteSync>b__0()
at Microsoft.Azure.Storage.Core.Util.CommonUtility.RunWithoutSynchronizationContext[T](Func`1 actionToRun)
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteSync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext)
at Microsoft.Azure.Storage.Blob.CloudBlob.DownloadRangeToStream(Stream target, Nullable`1 offset, Nullable`1 length, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
at Microsoft.Azure.Storage.Blob.CloudBlob.DownloadToStream(Stream target, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
This blog sounds like it has identified the issue - MemoryStream takes an int32 to set its capacity, with no option to use a larger number. I can't quite reconcile the value of int32.MaxValue (2147483647) with the specified size (1.5GiB in bytes is 1610612736 bytes) but it seems close enough to be the culprit. The blog suggests a solution to writing large content to Blob Storage, but I don't see how this could work for your use case.
If you definitely need to use MemoryStream to fulfil the needs of the library you are using, processing files this large will not be possible.
I am reading CSVs, so not totally sure this is directly applicable.
However, I tried to do what you are doing there at first, pulling the whole blob in and had this issue.
I was able to get significantly more info through our process by using something like this:
public async Task<string> ReadCsvRowRawAsync()
{
string currentRowRaw = await Reader.ReadLineAsync();
if (Reader.EndOfStream)
{
EndOfStream = true;
}
return currentRowRaw;
}
Going line by line allows only a small segment to be stored in memory.
I still get issues, but only on the largest of files.
Related
We have a replicated cache with 2 nodes, from time to time, we received this error and we aren't able to resolve: "Unable to cast object of type 'System.Int32' to type 'System.Collections.ArrayList'."
The stacktrace:
at Alachisoft.NCache.Web.Command.CommandResponse.ParseResponse()
at Alachisoft.NCache.Web.Caching.RemoteCache.Add(String key, Object value, CacheDependency dependency, CacheSyncDependency syncDependency, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, Int16 removeCallback, Int16 updateCallback, Int16 dsItemAddedCallback, Boolean isResyncExpiredItems, String group, String subGroup, Hashtable queryInfo, BitSet flagMap, String providerName, String resyncProviderName, EventDataFilter updateCallbackFilter, EventDataFilter removeCallabackFilter, Int64 size, String clientId)
at Alachisoft.NCache.Web.Caching.Cache.AddOperation(String key, Object value, CacheDependency dependency, CacheSyncDependency syncDependency, DateTime absoluteExpiration, TimeSpan slidingExpiration, CacheItemPriority priority, DSWriteOption dsWriteOption, CacheItemRemovedCallback onRemoveCallback, CacheItemUpdatedCallback onUpdateCallback, DataSourceItemsAddedCallback onDataSourceItemAdded, Boolean isResyncExpiredItems, String group, String subGroup, Tag[] tags, String providerName, String resyncProviderName, NamedTagsDictionary namedTags, CacheDataNotificationCallback cacheItemUdpatedCallback, CacheDataNotificationCallback cacheItemRemovedCallaback, EventDataFilter itemUpdateDataFilter, EventDataFilter itemRemovedDataFilter, Int64& size, Boolean allowQueryTags, String clientId, Int16 updateCallbackID, Int16 removeCallbackID, Int16 dsItemAddedCallbackID)
at Alachisoft.NCache.Web.Caching.Cache.Add(String key, CacheItem item, DSWriteOption dsWriteOption, DataSourceItemsAddedCallback onDataSourceItemAdded)
at Alachisoft.NCache.Web.Caching.Cache.Add(String key, CacheItem item)
In the log files we see:
...received response for request 118849, sender=<IP_Server_1>:7800, val=System.Byte[]
...received response for request 118849, sender=<IP_Server_2>:7800, val=Alachisoft.NCache.Common.DataStructures.Clustered.ClusteredArrayList
How can we resolve this problem?
The casting exception that you are getting is rather strange. This usually thrown on Cache get calls where you may be using an invalid cast. However, in this particular case it is on adding item to the cache which makes me believe this is on server side. Will need to review this - can you share some more details on this.
Please share complete application code snippet along with the flow on _cache.Add API within your code. Also share NCache version and edition information in order to review this in detail. You can run the "verifylicense.exe" tool (located at "C:\Program Files\NCache\bin\tools\verifylicense.exe") to check the current NCache version.
I think you should contact NCache support - support#alachisoft.com - their support is excellent - they should be able to expedite this for you.
I have json data that is being compressed using ServiceStacks's inbuilt ToOptimizedResult method. This has been working fine for a while now, recently though, when the data to be returned is high (50k+) rows etc. I get the Out Memory Error below:
System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
at System.Text.StringBuilder.ToString()
at ServiceStack.Text.JsonSerializer.SerializeToString(Object value, Type type)
at ServiceStack.Text.JsonSerializer.SerializeToString[T](T value)
at ServiceStack.ServiceModel.Serialization.JsonDataContractSerializer.SerializeToString[T](T obj)
at ServiceStack.Common.Web.HttpResponseFilter.SerializeToString(IRequestContext requestContext, Object response)
at ServiceStack.ServiceHost.RequestContextExtensions.ToOptimizedResult[T](IRequestContext requestContext, T dto)
at MyService.post(PostDDSReportDataSourceData Input) in MyService.vb:line 452
at lambda_method(Closure , Object , Object )
at ServiceStack.ServiceHost.ServiceRunner`1.Execute(IRequestContext requestContext, Object instance, TRequest request)
The weird part is that the exact same data is serialized ok on Dev, the error only appears in Production. The main solutions I've seen online recommend disabling buffering, however I've only seen examples that disable buffering entirely for the entire application. How can I disable buffering just for that one request?
Figured it out myself eventually. In the method simply turn off buffering like this:
CType(MyBase.Response.OriginalResponse, System.Web.HttpResponse).BufferOutput = False
As an addendum to the above solution, you will still receive this error if you store the json string in a variable. Only call the ToOptimized method when returning the result. Turning off buffering won't make a difference if you store the serialized string in a variable.
I eventually ended up serializing my list to a file, then sending the file down by returning an HttpResult below:
Dim PathToTheSerializedJsonFile as String = "C:\SomeFile.Json"
Using fl As StreamWriter = File.CreateText(PathToTheSerializedJsonFile)
Dim Serr As New Newtonsoft.Json.JsonSerializer()
Serr.Serialize(fl, Input)
End Using
Return New HttpResult(New FileInfo(PathToTheSerializedJsonFile),asAttachment:=True)
We are querying database using LINQ-SQL and then storing resulting master table objects in HTTP cache.
Later, the master objects are being used to query its children, using lazy loading. Here are the relevant pieces of code - I have recreated the scenario in a new proof-of-concept app:
if (HttpRuntime.Cache["c"] == null)
{
LockApp.Models.DBDataContext db = new Models.DBDataContext();
var master = db.Masters.ToList();
HttpRuntime.Cache.Add("c", master,
null, DateTime.Now.AddMonths(1),
TimeSpan.Zero, CacheItemPriority.Normal, null);
}
ViewBag.Data = (List<LockApp.Models.Master>)HttpRuntime.Cache["c"];
And here's the razor view that is iterating over master and detail objects:
#foreach(var m in ViewBag.Data){
#m.Id<nbsp></nbsp>
foreach(var d in m.Details){
#d.Id<nbsp></nbsp>
}
<br />
}
It works perfectly fine and caches the data correctly. However, it fails when there are multiple requests trying to hit the web site after cache is cleared - I am testing this using JMeter, basically hitting the site with many (50) parallel threads, and then touching web.config - I immediately start seeing one of the following two errors:
Index was outside the bounds of the array
at foreach(var d in m.Details)
this error never goes away, i.e. some data gets corrupted in cache
with following stack:
System.Collections.Generic.List`1.Add(T item) +34
System.Data.Linq.SqlClient.SqlConnectionManager.UseConnection(IConnectionUser user) +305
System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) +59
System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) +118
System.Data.Linq.SqlClient.CompiledQuery.Execute(IProvider provider, Object[] arguments) +99
System.Data.Linq.DeferredSourceFactory`1.ExecuteKeyQuery(Object[] keyValues) +402
System.Data.Linq.DeferredSourceFactory`1.Execute(Object instance) +888
System.Data.Linq.DeferredSource.GetEnumerator() +51
System.Data.Linq.EntitySet`1.Load() +107
System.Data.Linq.EntitySet`1.GetEnumerator() +13
System.Data.Linq.EntitySet`1.System.Collections.IEnumerable.GetEnumerator() +4
ASP._Page_Views_Home_Index_cshtml.Execute() in c:\Users\prc0092\Documents\Visual Studio 2012\Projects\LockApp\LockApp\Views\Home\Index.cshtml:16
or this error
ExecuteReader requires an open and available Connection. The connection's current state is open.
at the same line foreach(var d in m.Details)
this error does go away after a while if I stop hitting the site with parallel requests
with following stack
System.Data.SqlClient.SqlConnection.GetOpenConnection(String method) +5316460
System.Data.SqlClient.SqlConnection.ValidateConnectionForExecute(String method, SqlCommand command) +7
System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async) +155
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite) +82
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +53
System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +134
System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +41
System.Data.Common.DbCommand.ExecuteReader() +12
System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) +1306
System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) +118
System.Data.Linq.SqlClient.CompiledQuery.Execute(IProvider provider, Object[] arguments) +99
System.Data.Linq.DeferredSourceFactory`1.ExecuteKeyQuery(Object[] keyValues) +402
System.Data.Linq.DeferredSourceFactory`1.Execute(Object instance) +888
System.Data.Linq.DeferredSource.GetEnumerator() +51
System.Data.Linq.EntitySet`1.Load() +107
System.Data.Linq.EntitySet`1.GetEnumerator() +13
System.Data.Linq.EntitySet`1.System.Collections.IEnumerable.GetEnumerator() +4
ASP._Page_Views_Home_Index_cshtml.Execute() in c:\Users\prc0092\Documents\Visual Studio 2012\Projects\LockApp\LockApp\Views\Home\Index.cshtml:16
Different things I tried
Double locking
Doesn't help
private static object ThisLock = new object();
public ActionResult Index()
{
if (HttpRuntime.Cache["c"] == null)
{
lock (ThisLock)
{
if (HttpRuntime.Cache["c"] == null)
{
Loading child data upfront
Works, but requires constant maintenance as not all children should be loaded upfront, plus see next note
DataLoadOptions dlo = new DataLoadOptions();
dlo.LoadWith<Master>(b => b.Details);
db.LoadOptions = dlo;
Locking the master object while trying to access its children
Again, requires maintenance as all initial places where child is accessed need to be found - we are struggling with this as there are different entry paths into the site
#foreach(var m in ViewBag.Data){
#m.Id<nbsp></nbsp>
lock (m){
foreach(var d in m.Details){
#d.Id<nbsp></nbsp>
}
}
<br />
}
Switching to entity framework
This seems to still have (sometimes - much better than linq-sql) the "open connection" issue at certain number of parallel requests (50+ on core i7) - it does go away after a while as I mentioned and I haven't seen data corruption yet.
We may end up switching to EF completely as this seems to be the only viable path - assuming data corruption doesn't show up - that is to be tested on my actual project.
I am not optimistic though, as EF data context is not thread safe either, and I think the EF data objects carry their context with them. This is probably the only question that I don't have answer to yet.
Theories on why it's broken
It looks like storing LINQ-SQL object in http cache carries the data context with it. When this context is later used by multiple threads to access children, there is some type of concurrency issue that manifests itself in either temporary connectivity issue or complete data corruption of the child object. As there's no way to disconnect/reconnect the context from the LINQ object, it looks like the only suggestion is not to cache LINQ objects that need lazy-loading of their children - a substantial number of google searches I did does not seem to give you that advice, in fact sometimes it's opposite.
I have uploaded the complete project (for Visual Studio 2012 and SQL Server 2012)
https://docs.google.com/file/d/0B8CQRA9dD8POb3U5RGtCV3BMeU0/edit?usp=sharing
and a simple JMeter script that will hit your local machine with parallel requests:
https://docs.google.com/file/d/0B8CQRA9dD8POd1VYdGRDMEFQbEU/edit?usp=sharing
to test, start the site and run the test - then touch the web.config on the site
LockApp.Models.DBDataContext db = new Models.DBDataContext();
var master = db.Masters.ToList();
You should have a call to db.ObjectTrackingEnabled = false in between these two calls. Otherwise all of the objects will be tracked by the datacontext so that changes can be written back into the database. Since you're caching these objects to be read by multiple threads, you do not want this. (It's also more expensive even in single-threaded cases to track objects you won't change, so worth doing in other places).
Also, use LoadWith to eagerly load any properties you might want to access of these cached entities, so they are all loaded on the initial caching thread, rather than with (potentially mulitple) threads that try to access them.
Ultimately I am trying to address the same issue that is referenced in Loading any MVC page fails with the error “An item with the same key has already been added.” and An item with the same key has already been added. A duplicate of the first link is All MVC pages fail with the message an item with the same key has already been added but it has some additional pertinent information, confirming that it only effects MVC pages, while webforms and other aspects of the application that deal with appSettings continue to work without error.
I have now seen this four times in production and it has not been seen in any other environment (dev, test, UAT). I have closely examined and debugged through the source code of System.Web.WebPages and the relevant sections of the MVC stack but did not run into anything that stood out. This problem has persisted through a migration from MVC3 to MVC4, and the latest changeset from aspnetwebstack.codeplex.com does not appear to address this issue.
A quick summary of the issue:
Every MVC page is affected and completely unusable
WebForms and other aspects of the application that use appSettings continue to work just fine
Only an appPool restart will correct this issue
At least once and as referenced in an article above, this has happened after a regular time interval recycle of the appPool by IIS
This has happened during both low and high volume traffic periods
This has happened on multiple production servers, but the issue only affects a single server at any given time, as other servers continue serving MVC pages
The offending line of code is var items = new Lazy<Dictionary<object, object>>(() => appSettings.AllKeys.ToDictionary(key => key, key => (object)appSettings[key], comparer));, but it occurs when the lazy initialization is forced by requesting a value from items The appSettings variable is from System.Web.WebConfigurationManager.AppSettings which is a direct static reference to System.Configuration.ConfigurationManager.AppSettings. So I beleive the line is equivalent to: var items = new Lazy<Dictionary<object, object>>(() => System.Configuration.ConfigurationManager.AppSettings.AllKeys.ToDictionary(key => key, key => (object)appSettings[key], comparer));
I rarely suspect framework issues, but it appears that appSettings has two distinct keys that are the same (not the same as a NameValueCollection supporting multiple values for the same key). The comparer being used in the MVC stack is the StringComparer.OrdinalIgnoreCase which appears to match what is used by the configuration system. If this is a framework issue, the MVC stack appears to be very unforgiving when it forces the NameValueColleciton into a dictionary using the ToDictionary() extension method. I believe using appSettings.AllKeys.Distinct().ToDictionary(...) would probably allow the MVC stack to operate normally as the rest of the application does and be oblivious to the possibility of duplicate keys. This unforgiving nature appears to also contribute to the issue described in NullReferenceException in WebConfigScopeDictionary
Server stack trace:
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at System.Web.WebPages.Scope.WebConfigScopeDictionary.<>c__DisplayClass4.<.ctor>b__0()
at System.Lazy`1.CreateValue()
Exception rethrown at [0]:
at System.Lazy`1.get_Value()
at System.Web.WebPages.Scope.WebConfigScopeDictionary.TryGetValue(Object key, Object& value)
at System.Web.Mvc.ViewContext.ScopeGet[TValue](IDictionary`2 scope, String name, TValue defaultValue)
at System.Web.Mvc.ViewContext.ScopeCache..ctor(IDictionary`2 scope)
at System.Web.Mvc.ViewContext.ScopeCache.Get(IDictionary`2 scope, HttpContextBase httpContext)
at System.Web.Mvc.ViewContext.GetClientValidationEnabled(IDictionary`2 scope, HttpContextBase httpContext)
at System.Web.Mvc.Html.FormExtensions.FormHelper(HtmlHelper htmlHelper, String formAction, FormMethod method, IDictionary`2 htmlAttributes)
at ASP._Page_Areas_Client_Views_Equipment_Index_cshtml.Execute()
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<InvokeActionResultWithFilters>b__17()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult)
at System.Web.Mvc.Controller.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
To separate my question from the questions already asked, I will ask has anyone seen the configuration system be corrupted with multiple duplicate keys or where a NameValueCollection.AllKeys returns two identical keys? I know you can have multiple keys defined in the config file, but the last key wins, and that scenario does not reproduce this issue.
Although I am not alone in seeing this behavior multiple times, there are relatively few posts describing this issue, so I also suspect that it might be a configuration/environmental issue, but again, servers will run for months without experiencing this issue, and an appPool restart immediately corrects the problem.
I have mitigated this issue by forcing an appPool restart if a server starts seeing this error, but management is not happy about this "hacky" solution because some user will still experience an error.
Help?!?!?
EDIT:
Here is a contrived, cheezy test that can reproduce the scenario, but doesn't help in solving the issue. It happens during approx. 20% of the test runs. The code will blow up for other threading reasons, but it is the "Same key has already been added" error that is of interest.
[TestClass]
public class UnitTest1
{
readonly NameValueCollection _nameValueCollection = new NameValueCollection();
private Lazy<Dictionary<object, object>> _items;
[TestMethod]
public void ReproduceSameKeyHasAlreadyBeenAdded()
{
Thread[] threads = new Thread[1000];
for (int i = 0; i < 1000; i++)
{
ThreadStart threadStart = AddEntry;
Thread thread = new Thread(threadStart);
threads[i] = thread;
}
foreach (var thread in threads)
thread.Start();
Thread.Sleep(100);
_items = new Lazy<Dictionary<object, object>>(() => _nameValueCollection.AllKeys.ToDictionary(key => key, key => (object)_nameValueCollection[key], ScopeStorageComparer.Instance));
object value;
_items.Value.TryGetValue("4", out value); // approx. 20% of time, blows up here with mentioned error
Assert.IsTrue(value != null);
}
private int _counter;
private void AddEntry()
{
_counter++;
try
{ // add a bunch of even keys, every other one a duplicate
_nameValueCollection.Add((_counter%2) == 0 ? _counter.ToString() : (_counter + 1).ToString(), "some value");
}
catch {}
}
}
StackTrace:
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at UnitTestProject1.ReproduceSameKeyHasAlreadyBeenAdded.<TestMethod1>b__0() in c:\Git\AspNetWebStack\aspnetwebstack\UnitTestProject1\UnitTest1.cs:line 37
at System.Lazy`1.CreateValue()
We came across this same issue and finally tracked it down to dynamic updating of the ConfigurationManager.AppSettings collection. I have posted a full answer here: https://stackoverflow.com/a/17415830/2423407
Are you absolutely positive the error is occurring on the line where you are initializing items and not the line on which items is being used to add to some other dictionary (Static I would presume).
To me the most likely way this would occur is if the code was executed in parallel (by two concurrent users) and the second one executing causing the exception.
As a general workaround I usually initialize a strongly typed class with all configuration parameters as an auto-start provider (and add some strongly-typed type checking of the values as well, such as checking that an int is an int, etc) to avoid run-time errors.
This has the double benefit of loading these at warmup, not when the users want the info (better response performance) and thread-safety is supposedly guaranteed with them as well.
See if that doesn't fix your issue. If you do not want to do that I would at the very least try to execute the code that is failing for you with multiple threats hitting it, as my guess would be that you will see your error occur fairly reliably.
I have written code to send an email with a link to a URL, which the user has to click for confirmation.
Sample Link:
http://localhost:3531/VerificationModule/VerifyEmail.aspx?TemplateID=519457608&F960866879F669E=Tw5NpFeW9HsAqc_Ap5dmOwqkZ041pFQGYLxRV-puumtHsfhrTYtDe51uCbGV44Kc1X3n6cggsynfqRmh74ie535ymkvATeK5Jii11tOMIZDZ_GVB8QolLeMU5i6KWEZculKhM0IOhYFaMc-DsB
But when the user clicks the link, it gets opened in the browser, but displays the following error.
"Buffer cannot be null. Parameter name: buffer"
Please find below the stack trace:
[ArgumentNullException: Buffer cannot be null.
Parameter name: buffer]
System.IO.MemoryStream..ctor(Byte[] buffer, Boolean writable) +9629927
System.IO.MemoryStream..ctor(Byte[] buffer) +6
Auth.IdentityTokenXChangeData.Deserialize(String base64Package) +187
Auth.IdentityTokenXChange.TrySniffIdentityToken(HttpRequest req, String& sessionId, String& sessionTag, String& returnUrl) +244
Auth.IdentityModule.OnBeginRequest(Object sender, EventArgs e) +365
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +220
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +120`
This is eating up my day. Any suggestion would be of great help.
Got a clue on the error..
I believe the problem is with Encoded value in the QueryString
("F960866879F669E=Tw5NpFeW9HsAqc_Ap5dmOwqkZ041pFQGYLxRV-puumtHsfhrTYtDe51uCbGV44Kc1X3n6cggsynfqRmh74ie535ymkvATeK5Jii11tOMIZDZ_GVB8QolLeMU5i6KWEZculKhM0IOhYFaMc-DsB") -
The Base64 Decode is returning 'null' for some reasons.
Method -
'System.Web.HttpServerUtility.UrlTokenDecode
("F960866879F669E=Tw5NpFeW9HsAqc_Ap5dmOwqkZ041pFQGYLxRV-puumtHsfhrTYtDe51uCbGV44Kc1X3n6cggsynfqRmh74ie535ymkvATeK5Jii11tOMIZDZ_GVB8QolLeMU5i6KWEZculKhM0IOhYFaMc-DsB")'
Any idea on why it returns null? Is it not a valid Base64 encode?
It means the Auth.IdentityTokenXChangeData.Deserialize method creates a new MemoryStream instance with a null buffer argument.
This method seems specific to your code / environment (there is an Auth.IdentityModule in your site), so you need to take a look at it.