Question

I have a IIS-Hosted WCF service running on one server and a windows service running on another. The windows service acts as the slave and synchronizes the databases on each of the servers by connecting to the IIS-Hosted WCF service, with the use of MS Sync Framework.

I am storing the content of files in one of the tables that is beeing synchronized, and the entries can become a bit large (~10mb per entry). My problem is that when I try to synchronize these entries it takes a long time to synchronize.

The table being synchronized:

[Id] [int] IDENTITY(1,1) NOT NULL,
[Client] [uniqueidentifier] NOT NULL,
[Date] [datetime] NOT NULL,
[Content] [nvarchar](max) NOT NULL,

I’ve timed the synchronization with 1 entry with different content sizes to the following;

• 500kb – 1min 20sec
• 1mb – 3min
• 1,5mb – 6min 30sec
• 2mb – 9min 50sec

(The timings were approximately the same when debugging in Visual Studio with both services and both databases locally)

Does anyone have an explanation to why this takes so long?

WCF service config:

<configuration>
  <system.web>
    <httpRuntime maxRequestLength="2147483647" />
    <compilation debug="true" targetFramework="4.0"/>
  </system.web>

  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding closeTimeout="00:20:00" openTimeout="00:20:00" receiveTimeout="00:20:00" sendTimeout="00:20:00"
        allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
        maxBufferSize="2147483647" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"
        messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered"
        useDefaultWebProxy="true">
          <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647"/>
          <security mode="None">
            <transport clientCredentialType="None" proxyCredentialType="None"
            realm="" />
            <message clientCredentialType="UserName" algorithmSuite="Default" />
          </security>
        </binding>
      </basicHttpBinding>
    </bindings>

    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true" httpHelpPageEnabled="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>

    <serviceHostingEnvironment multipleSiteBindingsEnabled="true"/>
  </system.serviceModel>

  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

Windows service config:

<configuration>

  <system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicHttpBinding_ISyncServiceContract" closeTimeout="00:20:00" openTimeout="00:20:00" receiveTimeout="00:20:00" sendTimeout="00:20:00"
             allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
             maxBufferSize="2147483647" maxBufferPoolSize="2147483647" maxReceivedMessageSize="2147483647"
             messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true">
          <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647"/>
          <security mode="None">
            <transport clientCredentialType="None" proxyCredentialType="None" realm=""/>
            <message clientCredentialType="UserName" algorithmSuite="Default"/>
          </security>
        </binding>
      </basicHttpBinding>
    </bindings>

    <client>
      <endpoint address="http://localhost:60000/SyncService.svc" binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_ISyncServiceContract" contract="SyncServiceReference.ISyncServiceContract" name="BasicHttpBinding_ISyncServiceContract"/>
    </client>
  </system.serviceModel>

  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  </startup>

</configuration>

Answer 1

It seems the problem is the nvarchar(max) field when it contains too much data. I changed the field to varbinary(max) and now the synchronization of the same data is over in a fraction of the time used before.