Setup & Options

You can configure your synchronization model with some parameters, available through the SyncSetup and SyncOptions objects :

What’s the differences between SyncSetup and SyncOptions ?

  • SyncSetup contains all the parameters related to your schema, and shared between the server and all the clients.

    • In Http mode, the SyncSetup parameters are set by the Server and will be send to all Clients.

  • SyncOptions contains all the parameters not shared between the server and all the clients.


If we look at the SyncSetup object, we mainly have properties about your synced tables schema:

public class SyncSetup
    /// <summary>
    /// Gets or Sets the scope name
    /// </summary>
    public string ScopeName { get; set; }

    /// <summary>
    /// Gets or Sets all the synced tables
    /// </summary>
    public SetupTables Tables { get; set; }

    /// <summary>
    /// Specify all filters for each table
    /// </summary>
    public SetupFilters Filters { get; set; }

    /// <summary>
    /// Specify a prefix for naming stored procedure. Default is empty string
    /// </summary>
    public string StoredProceduresPrefix { get; set; }

    /// <summary>
    /// Specify a suffix for naming stored procedures. Default is empty string
    /// </summary>
    public string StoredProceduresSuffix { get; set; }

    /// <summary>
    /// Specify a prefix for naming stored procedure. Default is empty string
    /// </summary>
    public string TriggersPrefix { get; set; }

    /// <summary>
    /// Specify a suffix for naming stored procedures. Default is empty string
    /// </summary>
    public string TriggersSuffix { get; set; }

    /// <summary>
    /// Specify a prefix for naming tracking tables. Default is empty string
    /// </summary>
    public string TrackingTablesPrefix { get; set; }

    /// <summary>
    /// Specify a suffix for naming tracking tables.
    /// </summary>
    public string TrackingTablesSuffix { get; set; }


The SynchronizeAsync() method creates a SyncSetup instance automatically when called.

For instance, these two instructions are equivalent:

var tables = new string[] {"ProductCategory", "ProductModel", "Product",
    "Address", "Customer", "CustomerAddress", "SalesOrderHeader", "SalesOrderDetail" };

var agent = new SyncAgent(clientProvider, serverProvider);

var r = await agent.SynchronizeAsync(tables);
var setup = new SyncSetup("ProductCategory", "ProductModel", "Product",
        "Address", "Customer", "CustomerAddress", "SalesOrderHeader", "SalesOrderDetail");

var agent = new SyncAgent(clientProvider, serverProvider);

var r = await agent.SynchronizeAsync(setup);

The main advantage of using SyncSetup is you can personalize what you want from your database:



The schema feature is only avaialable for SQL Server

One great feature in SQL Server is the schema option.

You can configure your sync tables with schema if you target the SqlSyncProvider.

You have two way to configure schemas:

  • Directly during the tables declaration, as string.

var tables = new string[] { "SalesLT.ProductCategory", "SalesLT.ProductModel", "SalesLT.Product",
                                "Address", "Customer", "CustomerAddress"};
  • On each table, from the SyncSetup setup instance.

var setup = new SyncSetup ("ProductCategory", "ProductModel", "Product",
                            "Address", "Customer", "CustomerAddress");

setup.Tables["ProductCategory"].SchemaName = "SalesLt";
setup.Tables["ProductModel"].SchemaName = "SalesLt";
setup.Tables["Product"].SchemaName = "SalesLt";


Schemas are not replicated if you target SqliteSyncProvider or MySqlSyncProvider as client providers.

Filtering Columns

Once your SyncSetup instance is created (with your tables list), you can specify the columns you want to sync:

var setup = new SyncSetup("ProductCategory", "ProductModel", "Product",
        "Address", "Customer", "CustomerAddress", "SalesOrderHeader", "SalesOrderDetail" );

// Filter columns
setup.Tables["Customer"].Columns.AddRange(new string[] {
    "CustomerID", "EmployeeID", "NameStyle", "FirstName", "LastName" });

setup.Tables["Address"].Columns.AddRange(new string[] {
    "AddressID", "AddressLine1", "City", "PostalCode" });

For instance, table Customer and Address won’t sync all their columns, but only those specified.

Filtering Rows

From your SyncSetup instance, you can also specify a SetupFilter on each table, allowing you to filter rows.

setup.Filters.Add("Customer", "CustomerID");
setup.Filters.Add("CustomerAddress", "CustomerID");
setup.Filters.Add("SalesOrderHeader", "CustomerID", "SalesLT");

Tables Customer, CustomerAddress and SalesLT.SalesOrderHeader will filter their rows, based on the CustomerID column value.


Filtering rows is a quite complex thing. A full chapter is dedicated to rows filtering: Filters

Database configuration

You can personalize how are created the tracking tables, triggers and stored procedures tables in your database:

var setup = new SyncSetup(tables)
    StoredProceduresPrefix = "s",
    StoredProceduresSuffix = "",
    TrackingTablesPrefix = "t",
    TrackingTablesSuffix = "",
    TriggersPrefix = "",
    TriggersSuffix = "t"

HTTP mode

In a more realistic scenario, you will probably have a web proxy in front of your Server database.
You must provide your configuration values on the server side, not on the client side, since the server side will always override the values from the client.
As we saw in the Web chapter, we are using the ASP.NET Dependency injection system to create our Server remote provider.
It’s the best place to setup your sync configuration:
public void ConfigureServices(IServiceCollection services)
    services.AddSession(options => options.IdleTimeout = TimeSpan.FromMinutes(30));

    // Get a connection string for your server data source
    var connectionString = Configuration.GetSection("ConnectionStrings")["DefaultConnection"];

    // Create the setup used for your sync process
    var tables = new string[] {"ProductCategory",
                    "ProductDescription", "ProductModel",
                    "Product", "ProductModelProductDescription",
                    "Address", "Customer", "CustomerAddress",
                    "SalesOrderHeader", "SalesOrderDetail" };

    var setup = new SyncSetup(tables)
        StoredProceduresPrefix = "s",
        StoredProceduresSuffix = "",
        TrackingTablesPrefix = "t",
        TrackingTablesSuffix = "",
        TriggersPrefix = "",
        TriggersSuffix = "t"

    // add a SqlSyncProvider acting as the server hub
    services.AddSyncServer<SqlSyncProvider>(connectionString, setup);

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    if (env.IsDevelopment())

    app.UseEndpoints(endpoints => endpoints.MapControllers());


The prefix and suffix properties, are not shared betweeen server and client.


On the other side, SyncOptions can be customized on server and on client, with their own different values.
For instance, we can have a different value for the the BatchDirectory (representing the tmp directory when batch is enabled) on server and on client.
/// <summary>
/// This class determines all the options you can set on Client & Server,
/// that could potentially be different
/// </summary>
public class SyncOptions
    /// <summary>
    /// Gets or Sets the directory used for batch mode.
    /// Default value is [User Temp Path]/[DotmimSync]
    /// </summary>
    public string BatchDirectory { get; set; }

    /// <summary>
    /// Gets or Sets the directory where snapshots are stored.
    /// This value could be overwritten by server is used in an http mode
    /// </summary>
    public string SnapshotsDirectory { get; set; }

    /// <summary>
    /// Gets or Sets the size used (approximatively in kb, depending on the serializer)
    /// for each batch file, in batch mode.
    /// Default is 0 (no batch mode)
    /// </summary>
    public int BatchSize { get; set; }

    /// <summary>
    /// Gets or Sets the log level for sync operations. Default value is false.
    /// </summary>
    public bool UseVerboseErrors { get; set; }

    /// <summary>
    /// Gets or Sets if we should use the bulk operations. Default is true.
    /// If provider does not support bulk operations, this option is overrided to false.
    /// </summary>
    public bool UseBulkOperations { get; set; } = true;

    /// <summary>
    /// Gets or Sets if we should clean tracking table metadatas.
    /// </summary>
    public bool CleanMetadatas { get; set; } = true;

    /// <summary>
    /// Gets or Sets if we should cleaning tmp dir files after sync.
    /// </summary>
    public bool CleanFolder { get; set; } = true;

    /// <summary>
    /// Gets or Sets if we should disable constraints before making apply changes
    /// Default value is false
    /// </summary>
    public bool DisableConstraintsOnApplyChanges { get; set; } = false;

    /// <summary>
    /// Gets or Sets the scope_info table name. Default is scope_info
    /// On the server side, server scope table is prefixed with _server
    /// and history table with _history
    /// </summary>
    public string ScopeInfoTableName { get; set; }

    /// <summary>
    /// Gets or Sets the default conflict resolution policy. This value could potentially
    /// be ovewritten and replaced by the server
    /// </summary>
    public ConflictResolutionPolicy ConflictResolutionPolicy { get; set; }

    /// <summary>
    /// Gets or Sets the default logger used for logging purpose
    /// </summary>
    public ILogger Logger { get; set; }


If nothing is supplied when creating a new SyncAgent instance, a default SyncOptions is created with default values.

SyncOptions has some useful methods, you can rely on:

/// <summary>
/// Get the default Batch directory full path ([User Temp Path]/[DotmimSync])
/// </summary>
public static string GetDefaultUserBatchDiretory()

/// <summary>
/// Get the default user tmp folder
/// </summary>
public static string GetDefaultUserTempPath()

/// <summary>
/// Get the default sync tmp folder name (usually 'DotmimSync')
/// </summary>
public static string GetDefaultUserBatchDirectoryName()

Batch mode

Batch mode is an important options if you have to deal with over sized sync changes.

If you have a lot of changes to download from your server (or changes to upload from your client), maybe you don’t want to download / upload one big change object, stored in memory.
Even more, when you’re in a web environment, you don’t want to make a web request with everything inside of it, which could be way too heavy !

The BatchSize property from the SyncOptions object allows you to define the maximum size of any payload:

var clientOptions = new SyncOptions { BatchSize = 500 };


Be careful, the batch size value is a kb maximum size.
But The maximum size depends on compression, converters and so on…
Test and adjust the BatchSize value regarding your result and expectation.



You will find the complete sample here : Batch size sample

As an example, we make an insert of 100000 product category items in the server database, before making our sync:

Insert into ProductCategory (Name)
Select SUBSTRING(CONVERT(varchar(255), NEWID()), 0, 7)
Go 100000

By default, here is a sync process, where we download everything from the server, without any BatchSize option:

var agent = new SyncAgent(clientProvider, proxyClientProvider);
await agent.SynchronizeAsync(setup);

Here is the fiddler trace:

As you can see, the fiddler trace shows a http response around 16 Mb (approximatively 6 Mb compressed).
It could be even more, depending on the size of the selected changes from the server.

Here is the same sync, with the batch mode enabled:

// ----------------------------------
// Client side
// ----------------------------------
var clientOptions = new SyncOptions { BatchSize = 500 };

var agent = new SyncAgent(clientProvider, proxyClientProvider, clientOptions);
var progress = new SynchronousProgress<ProgressArgs>(pa =>
Console.WriteLine(String.Format("{0} -{1}\t {2}",
            pa.Context.SessionId, pa.Context.SyncStage, pa.Message));
var s = await agent.SynchronizeAsync(progress);


The client side dictates the batch size. The server is always adapting its payload, regarding the client ask.

Here is the fiddler trace:


And the progress of the sync process:

974f8be9-332d-4d6d-b881-7784b63b4bb7 - BeginSession      10:53:38.762    Session Id:974f8be9-332d-4d6d-b881-7784b63b4bb7
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ScopeLoaded       10:53:39.385    [Client] [DefaultScope] [Version ] Last sync: Last sync duration:0:0:0.0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - Provisioned       10:53:42.224    [Client] tables count:8 provision:Table, TrackingTable, StoredProcedures, Triggers
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesSelected   10:53:42.243    [Client] upserts:0 deletes:0 total:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:55.133    [Client] [ProductCategory] Modified applied:5171 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:55.702    [Client] [ProductCategory] Modified applied:10343 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:56.297    [Client] [ProductCategory] Modified applied:15515 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:56.891    [Client] [ProductCategory] Modified applied:20687 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:57.620    [Client] [ProductCategory] Modified applied:25859 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:58.280    [Client] [ProductCategory] Modified applied:31031 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:58.971    [Client] [ProductCategory] Modified applied:36203 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:53:59.682    [Client] [ProductCategory] Modified applied:41375 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:00.420    [Client] [ProductCategory] Modified applied:46547 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:01.169    [Client] [ProductCategory] Modified applied:51719 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:01.940    [Client] [ProductCategory] Modified applied:56891 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:02.657    [Client] [ProductCategory] Modified applied:62063 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:03.432    [Client] [ProductCategory] Modified applied:67235 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:04.192    [Client] [ProductCategory] Modified applied:72407 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:05.82     [Client] [ProductCategory] Modified applied:77579 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:05.930    [Client] [ProductCategory] Modified applied:82751 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:06.787    [Client] [ProductCategory] Modified applied:87923 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:07.672    [Client] [ProductCategory] Modified applied:93095 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:08.553    [Client] [ProductCategory] Modified applied:98267 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:08.972    [Client] [ProductCategory] Modified applied:100041 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.113    [Client] [ProductModel] Modified applied:128 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.183    [Client] [Product] Modified applied:198 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.208    [Client] [Product] Modified applied:295 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.255    [Client] [Address] Modified applied:450 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.329    [Client] [Customer] Modified applied:847 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.375    [Client] [CustomerAddress] Modified applied:417 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.414    [Client] [SalesOrderHeader] Modified applied:32 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplying   10:54:09.476    [Client] [SalesOrderDetail] Modified applied:542 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - ChangesApplied    10:54:09.636    [Client] applied:102752 resolved conflicts:0
974f8be9-332d-4d6d-b881-7784b63b4bb7 - EndSession        10:54:09.638    Session Id:974f8be9-332d-4d6d-b881-7784b63b4bb7
Synchronization done.
        Total changes  uploaded: 0
        Total changes  downloaded: 102752
        Total changes  applied: 102752
        Total resolved conflicts: 0
        Total duration :0:0:30.886

As you can see, most of the product category items come from different batch requests.


This option is only available when using SQL Server providers.

It allows you to use bulk operations from within SQL Server using Table Value Parameters as input to the stored procedures.

When using UseBulkOperations, each table will have new stored procedures and one table value parameter:

  • Stored procedure CustomerAddress_bulkdelete

  • Stored procedure CustomerAddress_bulkupdate

  • Table value parameter Customer_BulkType

Using this option will increase your performances, so do not hesitate to use it !


The CleanMetadatas option allows you to clean the _tracking tables from your client databases.

Once enabled, the client database will delete all metadatas from the tracking tables, after every successful sync.

Be careful, the delete method will:

  • Work only if client download something from server. If there is no changes downloaded and applied on the client, DeleteMetadasAsync is not called

  • Work only on T-2 metadatas. To be more secure, the T-1 values stays in the tracking tables.

You can also manually delete metadatas from both server or client, using the method DeleteMetadatasAsync, available from both LocalOrchestrator and RemoteOrchestrator:

var clientProvider = new SqlSyncProvider(DbHelper.GetDatabaseConnectionString(clientDbName));
var localOrchestrator = new LocalOrchestrator(clientProvider);
await localOrchestrator.DeleteMetadatasAsync();


If you’re using SqlSyncChangeTrackingProvider, the metadatas cleansing is automatically handled by the change tracking feature.


The DisableConstraintsOnApplyChanges will disable all constraint on your database, before the sync process is launched, and will be enabled after. Use it if you’re not sure of the table orders.


This option allows you to customize the scope info table name. Default is scope_info.

On the server side, server scope table is prefixed with _server and history table with _history


Define the default conflict resolution policy. See more here : Conflict