/// <summary>
        /// update configuration object with tables desc from server database
        /// </summary>
        public virtual async Task <SyncContext> CreateSnapshotAsync(SyncContext context, SyncSet schema,
                                                                    DbConnection connection, DbTransaction transaction, string batchDirectory, int batchSize, long remoteClientTimestamp,
                                                                    CancellationToken cancellationToken, IProgress <ProgressArgs> progress = null)
        {
            // create local directory
            if (!Directory.Exists(batchDirectory))
            {
                Directory.CreateDirectory(batchDirectory);
            }

            // numbers of batch files generated
            var batchIndex = 0;

            // create the in memory changes set
            var changesSet = new SyncSet();

            // Create a Schema set without readonly tables, attached to memory changes
            foreach (var table in schema.Tables)
            {
                DbSyncAdapter.CreateChangesTable(schema.Tables[table.TableName, table.SchemaName], changesSet);
            }

            var sb         = new StringBuilder();
            var underscore = "";

            if (context.Parameters != null)
            {
                foreach (var p in context.Parameters.OrderBy(p => p.Name))
                {
                    var cleanValue = new string(p.Value.ToString().Where(char.IsLetterOrDigit).ToArray());
                    var cleanName  = new string(p.Name.Where(char.IsLetterOrDigit).ToArray());

                    sb.Append($"{underscore}{cleanName}_{cleanValue}");
                    underscore = "_";
                }
            }

            var directoryName = sb.ToString();

            directoryName = string.IsNullOrEmpty(directoryName) ? "ALL" : directoryName;

            var directoryFullPath = Path.Combine(batchDirectory, directoryName);

            if (Directory.Exists(directoryFullPath))
            {
                Directory.Delete(directoryFullPath, true);
            }

            // batchinfo generate a schema clone with scope columns if needed
            var batchInfo = new BatchInfo(false, changesSet, batchDirectory, directoryName);

            // Clear tables, we will add only the ones we need in the batch info
            changesSet.Clear();

            foreach (var syncTable in schema.Tables)
            {
                var tableBuilder = this.GetTableBuilder(syncTable);
                var syncAdapter  = tableBuilder.CreateSyncAdapter(connection, transaction);

                // raise before event
                context.SyncStage = SyncStage.TableChangesSelecting;
                var tableChangesSelectingArgs = new TableChangesSelectingArgs(context, syncTable.TableName, connection, transaction);
                // launch interceptor if any
                await this.InterceptAsync(tableChangesSelectingArgs).ConfigureAwait(false);

                // Get Select initialize changes command
                var selectIncrementalChangesCommand = this.GetSelectChangesCommand(context, syncAdapter, syncTable, true);

                // Set parameters
                this.SetSelectChangesCommonParameters(context, syncTable, null, true, 0, selectIncrementalChangesCommand);

                // Get the reader
                using (var dataReader = selectIncrementalChangesCommand.ExecuteReader())
                {
                    // memory size total
                    double rowsMemorySize = 0L;

                    // Create a chnages table with scope columns
                    var changesSetTable = DbSyncAdapter.CreateChangesTable(schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                    while (dataReader.Read())
                    {
                        // Create a row from dataReader
                        var row = CreateSyncRowFromReader(dataReader, changesSetTable);

                        // Add the row to the changes set
                        changesSetTable.Rows.Add(row);

                        var fieldsSize     = ContainerTable.GetRowSizeFromDataRow(row.ToArray());
                        var finalFieldSize = fieldsSize / 1024d;

                        if (finalFieldSize > batchSize)
                        {
                            throw new RowOverSizedException(finalFieldSize.ToString());
                        }

                        // Calculate the new memory size
                        rowsMemorySize += finalFieldSize;

                        // Next line if we don't reach the batch size yet.
                        if (rowsMemorySize <= batchSize)
                        {
                            continue;
                        }

                        // add changes to batchinfo
                        batchInfo.AddChanges(changesSet, batchIndex, false);

                        // increment batch index
                        batchIndex++;

                        // we know the datas are serialized here, so we can flush  the set
                        changesSet.Clear();

                        // Recreate an empty ContainerSet and a ContainerTable
                        changesSet = new SyncSet();

                        changesSetTable = DbSyncAdapter.CreateChangesTable(schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                        // Init the row memory size
                        rowsMemorySize = 0L;
                    }
                }

                selectIncrementalChangesCommand.Dispose();
            }


            if (changesSet != null && changesSet.HasTables)
            {
                batchInfo.AddChanges(changesSet, batchIndex, true);
            }

            // Check the last index as the last batch
            batchInfo.EnsureLastBatch();

            batchInfo.Timestamp = remoteClientTimestamp;

            // Serialize on disk.
            var jsonConverter = new JsonConverter <BatchInfo>();

            var summaryFileName = Path.Combine(directoryFullPath, "summary.json");

            using (var f = new FileStream(summaryFileName, FileMode.CreateNew, FileAccess.ReadWrite))
            {
                var bytes = jsonConverter.Serialize(batchInfo);
                f.Write(bytes, 0, bytes.Length);
            }


            return(context);
        }
Esempio n. 2
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        /// <summary>
        /// Gets a batch of changes to synchronize when given batch size,
        /// destination knowledge, and change data retriever parameters.
        /// </summary>
        /// <returns>A DbSyncContext object that will be used to retrieve the modified data.</returns>
        internal virtual async Task <(SyncContext, BatchInfo, DatabaseChangesSelected)> InternalGetChangesAsync(
            SyncContext context, MessageGetChangesBatch message,
            DbConnection connection, DbTransaction transaction,
            CancellationToken cancellationToken, IProgress <ProgressArgs> progress)
        {
            // batch info containing changes
            BatchInfo batchInfo;


            // Statistics about changes that are selected
            DatabaseChangesSelected changesSelected;

            if (context.SyncWay == SyncWay.Upload && context.SyncType == SyncType.Reinitialize)
            {
                (batchInfo, changesSelected) = await this.InternalGetEmptyChangesAsync(message).ConfigureAwait(false);

                return(context, batchInfo, changesSelected);
            }

            // Call interceptor
            await this.InterceptAsync(new DatabaseChangesSelectingArgs(context, message, connection, transaction), cancellationToken).ConfigureAwait(false);

            // create local directory
            if (message.BatchSize > 0 && !string.IsNullOrEmpty(message.BatchDirectory) && !Directory.Exists(message.BatchDirectory))
            {
                Directory.CreateDirectory(message.BatchDirectory);
            }

            changesSelected = new DatabaseChangesSelected();

            // numbers of batch files generated
            var batchIndex = 0;

            // Check if we are in batch mode
            var isBatch = message.BatchSize > 0;

            // Create a batch info in memory (if !isBatch) or serialized on disk (if isBatch)
            // batchinfo generate a schema clone with scope columns if needed
            batchInfo = new BatchInfo(!isBatch, message.Schema, message.BatchDirectory);

            // Clean SyncSet, we will add only tables we need in the batch info
            var changesSet = new SyncSet();

            var cptSyncTable    = 0;
            var currentProgress = context.ProgressPercentage;

            foreach (var syncTable in message.Schema.Tables)
            {
                // tmp count of table for report progress pct
                cptSyncTable++;

                // Only table schema is replicated, no datas are applied
                if (syncTable.SyncDirection == SyncDirection.None)
                {
                    continue;
                }

                // if we are in upload stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Upload && syncTable.SyncDirection == SyncDirection.DownloadOnly)
                {
                    continue;
                }

                // if we are in download stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Download && syncTable.SyncDirection == SyncDirection.UploadOnly)
                {
                    continue;
                }

                // Get Command
                var selectIncrementalChangesCommand = await this.GetSelectChangesCommandAsync(context, syncTable, message.Setup, message.IsNew, connection, transaction);

                // Set parameters
                this.SetSelectChangesCommonParameters(context, syncTable, message.ExcludingScopeId, message.IsNew, message.LastTimestamp, selectIncrementalChangesCommand);

                // launch interceptor if any
                var args = new TableChangesSelectingArgs(context, syncTable, selectIncrementalChangesCommand, connection, transaction);
                await this.InterceptAsync(args, cancellationToken).ConfigureAwait(false);

                if (!args.Cancel && args.Command != null)
                {
                    // Statistics
                    var tableChangesSelected = new TableChangesSelected(syncTable.TableName, syncTable.SchemaName);

                    // Create a chnages table with scope columns
                    var changesSetTable = DbSyncAdapter.CreateChangesTable(message.Schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                    // Get the reader
                    using var dataReader = await args.Command.ExecuteReaderAsync().ConfigureAwait(false);

                    // memory size total
                    double rowsMemorySize = 0L;

                    while (dataReader.Read())
                    {
                        // Create a row from dataReader
                        var row = CreateSyncRowFromReader(dataReader, changesSetTable);

                        // Add the row to the changes set
                        changesSetTable.Rows.Add(row);

                        // Set the correct state to be applied
                        if (row.RowState == DataRowState.Deleted)
                        {
                            tableChangesSelected.Deletes++;
                        }
                        else if (row.RowState == DataRowState.Modified)
                        {
                            tableChangesSelected.Upserts++;
                        }

                        // calculate row size if in batch mode
                        if (isBatch)
                        {
                            var fieldsSize     = ContainerTable.GetRowSizeFromDataRow(row.ToArray());
                            var finalFieldSize = fieldsSize / 1024d;

                            if (finalFieldSize > message.BatchSize)
                            {
                                throw new RowOverSizedException(finalFieldSize.ToString());
                            }

                            // Calculate the new memory size
                            rowsMemorySize += finalFieldSize;

                            // Next line if we don't reach the batch size yet.
                            if (rowsMemorySize <= message.BatchSize)
                            {
                                continue;
                            }

                            // Check interceptor
                            var batchTableChangesSelectedArgs = new TableChangesSelectedArgs(context, changesSetTable, tableChangesSelected, connection, transaction);
                            await this.InterceptAsync(batchTableChangesSelectedArgs, cancellationToken).ConfigureAwait(false);

                            // add changes to batchinfo
                            await batchInfo.AddChangesAsync(changesSet, batchIndex, false, message.SerializerFactory, this).ConfigureAwait(false);

                            // increment batch index
                            batchIndex++;

                            // we know the datas are serialized here, so we can flush  the set
                            changesSet.Clear();

                            // Recreate an empty ContainerSet and a ContainerTable
                            changesSet = new SyncSet();

                            changesSetTable = DbSyncAdapter.CreateChangesTable(message.Schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                            // Init the row memory size
                            rowsMemorySize = 0L;
                        }
                    }

                    dataReader.Close();

                    // We don't report progress if no table changes is empty, to limit verbosity
                    if (tableChangesSelected.Deletes > 0 || tableChangesSelected.Upserts > 0)
                    {
                        changesSelected.TableChangesSelected.Add(tableChangesSelected);
                    }

                    // even if no rows raise the interceptor
                    var tableChangesSelectedArgs = new TableChangesSelectedArgs(context, changesSetTable, tableChangesSelected, connection, transaction);
                    await this.InterceptAsync(tableChangesSelectedArgs, cancellationToken).ConfigureAwait(false);

                    context.ProgressPercentage = currentProgress + (cptSyncTable * 0.2d / message.Schema.Tables.Count);

                    // only raise report progress if we have something
                    if (tableChangesSelectedArgs.TableChangesSelected.TotalChanges > 0)
                    {
                        this.ReportProgress(context, progress, tableChangesSelectedArgs);
                    }
                }
            }

            // We are in batch mode, and we are at the last batchpart info
            // Even if we don't have rows inside, we return the changesSet, since it contains at least schema
            if (changesSet != null && changesSet.HasTables && changesSet.HasRows)
            {
                await batchInfo.AddChangesAsync(changesSet, batchIndex, true, message.SerializerFactory, this).ConfigureAwait(false);
            }

            //Set the total rows count contained in the batch info
            batchInfo.RowsCount = changesSelected.TotalChangesSelected;

            // Check the last index as the last batch
            batchInfo.EnsureLastBatch();

            // Raise database changes selected
            if (changesSelected.TotalChangesSelected > 0 || changesSelected.TotalChangesSelectedDeletes > 0 || changesSelected.TotalChangesSelectedUpdates > 0)
            {
                var databaseChangesSelectedArgs = new DatabaseChangesSelectedArgs(context, message.LastTimestamp, batchInfo, changesSelected, connection);
                this.ReportProgress(context, progress, databaseChangesSelectedArgs);
                await this.InterceptAsync(databaseChangesSelectedArgs, cancellationToken).ConfigureAwait(false);
            }

            return(context, batchInfo, changesSelected);
        }
Esempio n. 3
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        /// <summary>
        /// Enumerate all internal changes, no batch mode
        /// </summary>
        internal async Task <(BatchInfo, DatabaseChangesSelected)> EnumerateChangesInBatchesInternalAsync
            (SyncContext context, ScopeInfo scopeInfo, int downloadBatchSizeInKB, DmSet configTables, string batchDirectory, ConflictResolutionPolicy policy, ICollection <FilterClause> filters)
        {
            DmTable dmTable = null;
            // memory size total
            double memorySizeFromDmRows = 0L;

            var batchIndex = 0;

            // this batch info won't be in memory, it will be be batched
            var batchInfo = new BatchInfo(false, batchDirectory);

            // directory where all files will be stored
            batchInfo.GenerateNewDirectoryName();

            // Create stats object to store changes count
            var changes = new DatabaseChangesSelected();

            using (var connection = this.CreateConnection())
            {
                try
                {
                    // Open the connection
                    await connection.OpenAsync();

                    using (var transaction = connection.BeginTransaction())
                    {
                        // create the in memory changes set
                        var changesSet = new DmSet(configTables.DmSetName);

                        foreach (var tableDescription in configTables.Tables)
                        {
                            // if we are in upload stage, so check if table is not download only
                            if (context.SyncWay == SyncWay.Upload && tableDescription.SyncDirection == SyncDirection.DownloadOnly)
                            {
                                continue;
                            }

                            // if we are in download stage, so check if table is not download only
                            if (context.SyncWay == SyncWay.Download && tableDescription.SyncDirection == SyncDirection.UploadOnly)
                            {
                                continue;
                            }

                            var builder     = this.GetDatabaseBuilder(tableDescription);
                            var syncAdapter = builder.CreateSyncAdapter(connection, transaction);

                            // raise before event
                            context.SyncStage = SyncStage.TableChangesSelecting;
                            var tableChangesSelectingArgs = new TableChangesSelectingArgs(context, tableDescription.TableName, connection, transaction);
                            // launc interceptor if any
                            await this.InterceptAsync(tableChangesSelectingArgs);

                            // Get Command
                            DbCommand     selectIncrementalChangesCommand;
                            DbCommandType dbCommandType;

                            if (this.CanBeServerProvider && context.Parameters != null && context.Parameters.Count > 0 && filters != null && filters.Count > 0)
                            {
                                var tableFilters = filters
                                                   .Where(f => f.TableName.Equals(tableDescription.TableName, StringComparison.InvariantCultureIgnoreCase));

                                if (tableFilters != null && tableFilters.Count() > 0)
                                {
                                    dbCommandType = DbCommandType.SelectChangesWitFilters;
                                    selectIncrementalChangesCommand = syncAdapter.GetCommand(dbCommandType, tableFilters);
                                    if (selectIncrementalChangesCommand == null)
                                    {
                                        throw new Exception("Missing command 'SelectIncrementalChangesCommand' ");
                                    }
                                    syncAdapter.SetCommandParameters(dbCommandType, selectIncrementalChangesCommand, tableFilters);
                                }
                                else
                                {
                                    dbCommandType = DbCommandType.SelectChanges;
                                    selectIncrementalChangesCommand = syncAdapter.GetCommand(dbCommandType);
                                    if (selectIncrementalChangesCommand == null)
                                    {
                                        throw new Exception("Missing command 'SelectIncrementalChangesCommand' ");
                                    }
                                    syncAdapter.SetCommandParameters(dbCommandType, selectIncrementalChangesCommand);
                                }
                            }
                            else
                            {
                                dbCommandType = DbCommandType.SelectChanges;
                                selectIncrementalChangesCommand = syncAdapter.GetCommand(dbCommandType);
                                if (selectIncrementalChangesCommand == null)
                                {
                                    throw new Exception("Missing command 'SelectIncrementalChangesCommand' ");
                                }
                                syncAdapter.SetCommandParameters(dbCommandType, selectIncrementalChangesCommand);
                            }



                            dmTable = this.BuildChangesTable(tableDescription.TableName, configTables);

                            try
                            {
                                // Set commons parameters
                                SetSelectChangesCommonParameters(context, scopeInfo, selectIncrementalChangesCommand);

                                // Set filter parameters if any
                                // Only on server side
                                if (this.CanBeServerProvider && context.Parameters != null && context.Parameters.Count > 0 && filters != null && filters.Count > 0)
                                {
                                    var filterTable = filters.Where(f => f.TableName.Equals(tableDescription.TableName, StringComparison.InvariantCultureIgnoreCase)).ToList();

                                    if (filterTable != null && filterTable.Count > 0)
                                    {
                                        foreach (var filter in filterTable)
                                        {
                                            var parameter = context.Parameters.FirstOrDefault(p => p.ColumnName.Equals(filter.ColumnName, StringComparison.InvariantCultureIgnoreCase) && p.TableName.Equals(filter.TableName, StringComparison.InvariantCultureIgnoreCase));

                                            if (parameter != null)
                                            {
                                                DbManager.SetParameterValue(selectIncrementalChangesCommand, parameter.ColumnName, parameter.Value);
                                            }
                                        }
                                    }
                                }

                                this.AddTrackingColumns <int>(dmTable, "sync_row_is_tombstone");

                                // Statistics
                                var tableChangesSelected = new TableChangesSelected
                                {
                                    TableName = tableDescription.TableName
                                };

                                changes.TableChangesSelected.Add(tableChangesSelected);

                                // Get the reader
                                using (var dataReader = selectIncrementalChangesCommand.ExecuteReader())
                                {
                                    while (dataReader.Read())
                                    {
                                        var dmRow = this.CreateRowFromReader(dataReader, dmTable);

                                        var state = DmRowState.Unchanged;

                                        state = this.GetStateFromDmRow(dmRow, scopeInfo);

                                        // If the row is not deleted inserted or modified, go next
                                        if (state != DmRowState.Deleted && state != DmRowState.Modified && state != DmRowState.Added)
                                        {
                                            continue;
                                        }

                                        var fieldsSize = DmTableSurrogate.GetRowSizeFromDataRow(dmRow);
                                        var dmRowSize  = fieldsSize / 1024d;

                                        if (dmRowSize > downloadBatchSizeInKB)
                                        {
                                            var exc = $"Row is too big ({dmRowSize} kb.) for the current Configuration.DownloadBatchSizeInKB ({downloadBatchSizeInKB} kb.) Aborting Sync...";
                                            throw new Exception(exc);
                                        }

                                        // Calculate the new memory size
                                        memorySizeFromDmRows = memorySizeFromDmRows + dmRowSize;

                                        // add row
                                        dmTable.Rows.Add(dmRow);
                                        tableChangesSelected.TotalChanges++;

                                        // acceptchanges before modifying
                                        dmRow.AcceptChanges();

                                        // Set the correct state to be applied
                                        if (state == DmRowState.Deleted)
                                        {
                                            dmRow.Delete();
                                            tableChangesSelected.Deletes++;
                                        }
                                        else if (state == DmRowState.Added)
                                        {
                                            dmRow.SetAdded();
                                            tableChangesSelected.Inserts++;
                                        }
                                        else if (state == DmRowState.Modified)
                                        {
                                            dmRow.SetModified();
                                            tableChangesSelected.Updates++;
                                        }

                                        // We exceed the memorySize, so we can add it to a batch
                                        if (memorySizeFromDmRows > downloadBatchSizeInKB)
                                        {
                                            // Since we dont need this column anymore, remove it
                                            this.RemoveTrackingColumns(dmTable, "sync_row_is_tombstone");

                                            changesSet.Tables.Add(dmTable);

                                            // generate the batch part info
                                            batchInfo.GenerateBatchInfo(batchIndex, changesSet);

                                            // increment batch index
                                            batchIndex++;

                                            changesSet.Clear();

                                            // Recreate an empty DmSet, then a dmTable clone
                                            changesSet = new DmSet(configTables.DmSetName);
                                            dmTable    = dmTable.Clone();
                                            this.AddTrackingColumns <int>(dmTable, "sync_row_is_tombstone");

                                            // Init the row memory size
                                            memorySizeFromDmRows = 0L;

                                            // SyncProgress & interceptor
                                            context.SyncStage = SyncStage.TableChangesSelected;
                                            var loopTableChangesSelectedArgs = new TableChangesSelectedArgs(context, tableChangesSelected, connection, transaction);
                                            this.ReportProgress(context, loopTableChangesSelectedArgs);
                                            await this.InterceptAsync(loopTableChangesSelectedArgs);
                                        }
                                    }

                                    // Since we dont need this column anymore, remove it
                                    this.RemoveTrackingColumns(dmTable, "sync_row_is_tombstone");

                                    context.SyncStage = SyncStage.TableChangesSelected;

                                    changesSet.Tables.Add(dmTable);

                                    // Init the row memory size
                                    memorySizeFromDmRows = 0L;

                                    // Event progress & interceptor
                                    context.SyncStage = SyncStage.TableChangesSelected;
                                    var tableChangesSelectedArgs = new TableChangesSelectedArgs(context, tableChangesSelected, connection, transaction);
                                    this.ReportProgress(context, tableChangesSelectedArgs);
                                    await this.InterceptAsync(tableChangesSelectedArgs);
                                }
                            }
                            catch (Exception)
                            {
                                throw;
                            }
                            finally
                            {
                            }
                        }

                        // We are in batch mode, and we are at the last batchpart info
                        if (changesSet != null && changesSet.HasTables && changesSet.HasChanges())
                        {
                            var batchPartInfo = batchInfo.GenerateBatchInfo(batchIndex, changesSet);

                            if (batchPartInfo != null)
                            {
                                batchPartInfo.IsLastBatch = true;
                            }
                        }

                        transaction.Commit();
                    }
                }
                catch (Exception)
                {
                    throw;
                }
                finally
                {
                    if (connection != null && connection.State == ConnectionState.Open)
                    {
                        connection.Close();
                    }
                }
            }

            return(batchInfo, changes);
        }
Esempio n. 4
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        /// <summary>
        /// Gets changes rows count estimation,
        /// </summary>
        internal virtual async Task <(SyncContext, DatabaseChangesSelected)> InternalGetEstimatedChangesCountAsync(
            SyncContext context, MessageGetChangesBatch message,
            DbConnection connection, DbTransaction transaction,
            CancellationToken cancellationToken, IProgress <ProgressArgs> progress)
        {
            // Call interceptor
            await this.InterceptAsync(new DatabaseChangesSelectingArgs(context, message, connection, transaction), cancellationToken).ConfigureAwait(false);

            // Create stats object to store changes count
            var changes = new DatabaseChangesSelected();

            if (context.SyncWay == SyncWay.Upload && context.SyncType == SyncType.Reinitialize)
            {
                return(context, changes);
            }

            foreach (var syncTable in message.Schema.Tables)
            {
                // Only table schema is replicated, no datas are applied
                if (syncTable.SyncDirection == SyncDirection.None)
                {
                    continue;
                }

                // if we are in upload stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Upload && syncTable.SyncDirection == SyncDirection.DownloadOnly)
                {
                    continue;
                }

                // if we are in download stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Download && syncTable.SyncDirection == SyncDirection.UploadOnly)
                {
                    continue;
                }

                // Get Command
                var command = await this.GetSelectChangesCommandAsync(context, syncTable, message.Setup, message.IsNew, connection, transaction);

                // Set parameters
                this.SetSelectChangesCommonParameters(context, syncTable, message.ExcludingScopeId, message.IsNew, message.LastTimestamp, command);

                // launch interceptor if any
                var args = new TableChangesSelectingArgs(context, syncTable, command, connection, transaction);
                await this.InterceptAsync(args, cancellationToken).ConfigureAwait(false);

                if (args.Cancel || args.Command == null)
                {
                    continue;
                }

                // Statistics
                var tableChangesSelected = new TableChangesSelected(syncTable.TableName, syncTable.SchemaName);

                // Get the reader
                using var dataReader = await args.Command.ExecuteReaderAsync().ConfigureAwait(false);

                while (dataReader.Read())
                {
                    bool isTombstone = false;
                    for (var i = 0; i < dataReader.FieldCount; i++)
                    {
                        if (dataReader.GetName(i) == "sync_row_is_tombstone")
                        {
                            isTombstone = Convert.ToInt64(dataReader.GetValue(i)) > 0;
                            break;
                        }
                    }

                    // Set the correct state to be applied
                    if (isTombstone)
                    {
                        tableChangesSelected.Deletes++;
                    }
                    else
                    {
                        tableChangesSelected.Upserts++;
                    }
                }

                dataReader.Close();

                // Check interceptor
                var changesArgs = new TableChangesSelectedArgs(context, null, tableChangesSelected, connection, transaction);
                await this.InterceptAsync(changesArgs, cancellationToken).ConfigureAwait(false);

                if (tableChangesSelected.Deletes > 0 || tableChangesSelected.Upserts > 0)
                {
                    changes.TableChangesSelected.Add(tableChangesSelected);
                }
            }

            // Raise database changes selected
            var databaseChangesSelectedArgs = new DatabaseChangesSelectedArgs(context, message.LastTimestamp, null, changes, connection);

            this.ReportProgress(context, progress, databaseChangesSelectedArgs);
            await this.InterceptAsync(databaseChangesSelectedArgs, cancellationToken).ConfigureAwait(false);

            return(context, changes);
        }
        /// <summary>
        /// Gets a batch of changes to synchronize when given batch size,
        /// destination knowledge, and change data retriever parameters.
        /// </summary>
        /// <returns>A DbSyncContext object that will be used to retrieve the modified data.</returns>
        public virtual async Task <(SyncContext, BatchInfo, DatabaseChangesSelected)> GetChangeBatchAsync(
            SyncContext context, MessageGetChangesBatch message,
            DbConnection connection, DbTransaction transaction,
            CancellationToken cancellationToken, IProgress <ProgressArgs> progress = null)
        {
            // batch info containing changes
            BatchInfo batchInfo;

            // Statistics about changes that are selected
            DatabaseChangesSelected changesSelected;

            if (context.SyncWay == SyncWay.Upload && context.SyncType == SyncType.Reinitialize)
            {
                (batchInfo, changesSelected) = this.GetEmptyChanges(message);
                return(context, batchInfo, changesSelected);
            }

            // Check if the provider is not outdated
            var isOutdated = this.IsRemoteOutdated();

            // Get a chance to make the sync even if it's outdated
            if (isOutdated)
            {
                var outdatedArgs = new OutdatedArgs(context, null, null);

                // Interceptor
                await this.InterceptAsync(outdatedArgs).ConfigureAwait(false);

                if (outdatedArgs.Action != OutdatedAction.Rollback)
                {
                    context.SyncType = outdatedArgs.Action == OutdatedAction.Reinitialize ? SyncType.Reinitialize : SyncType.ReinitializeWithUpload;
                }

                if (outdatedArgs.Action == OutdatedAction.Rollback)
                {
                    throw new OutOfDateException();
                }
            }

            // create local directory
            if (message.BatchSize > 0 && !string.IsNullOrEmpty(message.BatchDirectory) && !Directory.Exists(message.BatchDirectory))
            {
                Directory.CreateDirectory(message.BatchDirectory);
            }

            // numbers of batch files generated
            var batchIndex = 0;

            // Check if we are in batch mode
            var isBatch = message.BatchSize > 0;

            // Create stats object to store changes count
            var changes = new DatabaseChangesSelected();

            // create the in memory changes set
            var changesSet = new SyncSet(message.Schema.ScopeName);

            // Create a Schema set without readonly columns, attached to memory changes
            foreach (var table in message.Schema.Tables)
            {
                DbSyncAdapter.CreateChangesTable(message.Schema.Tables[table.TableName, table.SchemaName], changesSet);
            }

            // Create a batch info in memory (if !isBatch) or serialized on disk (if isBatch)
            // batchinfo generate a schema clone with scope columns if needed
            batchInfo = new BatchInfo(!isBatch, changesSet, message.BatchDirectory);

            // Clear tables, we will add only the ones we need in the batch info
            changesSet.Clear();

            foreach (var syncTable in message.Schema.Tables)
            {
                // if we are in upload stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Upload && syncTable.SyncDirection == SyncDirection.DownloadOnly)
                {
                    continue;
                }

                // if we are in download stage, so check if table is not download only
                if (context.SyncWay == SyncWay.Download && syncTable.SyncDirection == SyncDirection.UploadOnly)
                {
                    continue;
                }

                var tableBuilder = this.GetTableBuilder(syncTable);
                var syncAdapter  = tableBuilder.CreateSyncAdapter(connection, transaction);

                // raise before event
                context.SyncStage = SyncStage.TableChangesSelecting;
                var tableChangesSelectingArgs = new TableChangesSelectingArgs(context, syncTable.TableName, connection, transaction);
                // launch interceptor if any
                await this.InterceptAsync(tableChangesSelectingArgs).ConfigureAwait(false);

                // Get Command
                var selectIncrementalChangesCommand = this.GetSelectChangesCommand(context, syncAdapter, syncTable, message.IsNew);

                // Set parameters
                this.SetSelectChangesCommonParameters(context, syncTable, message.ExcludingScopeId, message.IsNew, message.LastTimestamp, selectIncrementalChangesCommand);

                // Statistics
                var tableChangesSelected = new TableChangesSelected(syncTable.TableName);

                // Get the reader
                using (var dataReader = selectIncrementalChangesCommand.ExecuteReader())
                {
                    // memory size total
                    double rowsMemorySize = 0L;

                    // Create a chnages table with scope columns
                    var changesSetTable = DbSyncAdapter.CreateChangesTable(message.Schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                    while (dataReader.Read())
                    {
                        // Create a row from dataReader
                        var row = CreateSyncRowFromReader(dataReader, changesSetTable);

                        // Add the row to the changes set
                        changesSetTable.Rows.Add(row);

                        // Set the correct state to be applied
                        if (row.RowState == DataRowState.Deleted)
                        {
                            tableChangesSelected.Deletes++;
                        }
                        else if (row.RowState == DataRowState.Modified)
                        {
                            tableChangesSelected.Upserts++;
                        }

                        // calculate row size if in batch mode
                        if (isBatch)
                        {
                            var fieldsSize     = ContainerTable.GetRowSizeFromDataRow(row.ToArray());
                            var finalFieldSize = fieldsSize / 1024d;

                            if (finalFieldSize > message.BatchSize)
                            {
                                throw new RowOverSizedException(finalFieldSize.ToString());
                            }

                            // Calculate the new memory size
                            rowsMemorySize += finalFieldSize;

                            // Next line if we don't reach the batch size yet.
                            if (rowsMemorySize <= message.BatchSize)
                            {
                                continue;
                            }

                            // add changes to batchinfo
                            batchInfo.AddChanges(changesSet, batchIndex, false);

                            // increment batch index
                            batchIndex++;

                            // we know the datas are serialized here, so we can flush  the set
                            changesSet.Clear();

                            // Recreate an empty ContainerSet and a ContainerTable
                            changesSet = new SyncSet(message.Schema.ScopeName);

                            changesSetTable = DbSyncAdapter.CreateChangesTable(message.Schema.Tables[syncTable.TableName, syncTable.SchemaName], changesSet);

                            // Init the row memory size
                            rowsMemorySize = 0L;
                        }
                    }
                }

                selectIncrementalChangesCommand.Dispose();

                context.SyncStage = SyncStage.TableChangesSelected;

                if (tableChangesSelected.Deletes > 0 || tableChangesSelected.Upserts > 0)
                {
                    changes.TableChangesSelected.Add(tableChangesSelected);
                }

                // Event progress & interceptor
                context.SyncStage = SyncStage.TableChangesSelected;
                var tableChangesSelectedArgs = new TableChangesSelectedArgs(context, tableChangesSelected, connection, transaction);
                this.ReportProgress(context, progress, tableChangesSelectedArgs);
                await this.InterceptAsync(tableChangesSelectedArgs).ConfigureAwait(false);
            }

            // We are in batch mode, and we are at the last batchpart info
            // Even if we don't have rows inside, we return the changesSet, since it contains at leaset schema
            if (changesSet != null && changesSet.HasTables)
            {
                batchInfo.AddChanges(changesSet, batchIndex, true);
            }

            // Check the last index as the last batch
            batchInfo.EnsureLastBatch();

            return(context, batchInfo, changes);
        }