Batch delete in Windows Azure Table Storage

问题

I'm trying to delete all entities between 2 dates (i.e. 2 partition keys) in the WADLogsTable. So far, the best code I've found is this one (from http://wintellect.com/blogs/jlane/deleting-entities-in-windows-azure-table-storage):

private static void DeleteAllEntitiesInBatches(CloudTable table, Expression<Func<DynamicTableEntity, bool>> filters)
        {
            Action<IEnumerable<DynamicTableEntity>> processor = entities =>
            {
                var batches = new Dictionary<string, TableBatchOperation>();

                foreach (var entity in entities)
                {
                    TableBatchOperation batch = null;

                    if (batches.TryGetValue(entity.PartitionKey, out batch) == false)
                    {
                        batches[entity.PartitionKey] = batch = new TableBatchOperation();
                    }

                    batch.Add(TableOperation.Delete(entity));

                    if (batch.Count == 100)
                    {
                        table.ExecuteBatch(batch);
                        batches[entity.PartitionKey] = new TableBatchOperation();
                    }
                }

                foreach (var batch in batches.Values)
                {
                    if (batch.Count > 0)
                    {
                        table.ExecuteBatch(batch);
                    }
                }
            };

            ProcessEntities(table, processor, filters);
        }

        private static void ProcessEntities(CloudTable table, Action<IEnumerable<DynamicTableEntity>> processor, Expression<Func<DynamicTableEntity, bool>> filters)
        {
            TableQuerySegment<DynamicTableEntity> segment = null;

            while (segment == null || segment.ContinuationToken != null)
            {
                if (filters == null)
                {
                    segment = table.ExecuteQuerySegmented(new TableQuery().Take(100), segment == null ? null : segment.ContinuationToken);
                }
                else
                {
                    var query = table.CreateQuery<DynamicTableEntity>().Where(filters).Take(100).AsTableQuery();
                    segment = query.ExecuteSegmented(segment == null ? null : segment.ContinuationToken);
                }

                processor(segment.Results);
            }
        }

But I don't know what I should pass as the "filters" parameter. I came up with this rather naive attempt:

Expression<Func<DynamicTableEntity, bool>> filters = e => long.Parse(e.PartitionKey) >= startTicks && long.Parse(e.PartitionKey) <= endTicks;

But that doesn't work. At runtime, I get the following error:

The expression ((Parse([10007].PartitionKey) >= 635109048000000000) And (Parse([10007].PartitionKey) <= 635115960000000000)) is not supported.

I don't know if my problem is related to Azure tables or Expression but any help will be appreciated.

EDIT: I'd be happy to provide with more info if needed.

回答1:

I got an answer on another forum:

var startTicks = string.Format("{0:0000000000000000000}", start);
var endTicks = string.Format("{0:0000000000000000000}", end);
Expression<Func<DynamicTableEntity, bool>> filters = e => e.PartitionKey.CompareTo(startTicks) >= 0 && e.PartitionKey.CompareTo(endTicks) <= 0;

来源：https://stackoverflow.com/questions/22684881/batch-delete-in-windows-azure-table-storage

标签

azure

azure-table-storage