删除 Azure 存储中的批处理操作

Question

我一直在尝试实现 DAO 方法，用于 Azure 存储实体的删除操作。使用表删除操作是可以的。

TableOperation deleteEntity = TableOperation.delete(entity);

但是当我使用批处理操作尝试它时，它不受支持。

非常感谢克服此问题的任何建议。

Answer 1

但是

当我使用批处理操作尝试它时，它不受支持。

我假设您可以按分区键对要删除的项目进行分组，然后执行TableBatchOperation.

在这里，我通过C#语言编写了一个帮助程序类来实现此目的，您可以参考它：

public class TableBatchHelper<T> where T : ITableEntity
{
const int batchMaxSize = 100;
public static IEnumerable<TableBatchOperation> GetBatchesForDelete(IEnumerable<T> items)
{
var list = new List<TableBatchOperation>();
var partitionGroups = items.GroupBy(arg => arg.PartitionKey).ToArray();
foreach (var group in partitionGroups)
{
T[] groupList = group.ToArray();
int offSet = batchMaxSize;
T[] entities = groupList.Take(offSet).ToArray();
while (entities.Any())
{
var tableBatchOperation = new TableBatchOperation();
foreach (var entity in entities)
{
tableBatchOperation.Add(TableOperation.Delete(entity));
}
list.Add(tableBatchOperation);
entities = groupList.Skip(offSet).Take(batchMaxSize).ToArray();
offSet += batchMaxSize;
}
}
return list;
}
public static async Task BatchDeleteAsync(CloudTable table, IEnumerable<T> items)
{
var batches = GetBatchesForDelete(items);
await Task.WhenAll(batches.Select(table.ExecuteBatchAsync));
}
}

然后，您可以按如下方式执行批量删除：

await TableBatchHelper<ClassName>.BatchDeleteAsync(cloudTable,items);

或

var batches = TableBatchHelper<ClassName>.GetBatchesForDelete(entities);
Parallel.ForEach(batches, new ParallelOptions()
{
MaxDegreeOfParallelism = 5
}, (batchOperation) =>
{
try
{
table.ExecuteBatch(batchOperation);
Console.WriteLine("Writing {0} records", batchOperation.Count);
}
catch (Exception ex)
{
Console.WriteLine("ExecuteBatch throw a exception:" + ex.Message);
}
});

Answer 2

不，那是不使用块操作的代码。以下是包含块操作的代码。很抱歉没有提到这一点

TableBatchOperation batchOperation = new TableBatchOperation();
List<TableBatchOperation> list = new ArrayList<>();
if (partitionQuery != null) {
for (AzureLocationData entity : cloudTable.execute(partitionQuery)) {
batchOperation.add(TableOperation.delete(entity));
list.add(batchOperation);    //exception thrown line
}
try {
cloudTable.execute((TableOperation) batchOperation);
} catch (StorageException e) {
e.printStackTrace();
}
}

Answer 3

public void deleteLocationsForDevice(String id) {
logger.info("Going to delete location data for Device [{}]", id);
// Create a filter condition where the partition key is deviceId.
String partitionFilter = TableQuery.generateFilterCondition(
PARTITION_KEY,
TableQuery.QueryComparisons.EQUAL,
id);
// Specify a partition query, using  partition key filter.
TableQuery<AzureLocationData> partitionQuery =
TableQuery.from(AzureLocationData.class)
.where(partitionFilter);

if (partitionQuery != null) {
for (AzureLocationData entity : cloudTable.execute(partitionQuery)) {
TableOperation deleteEntity = TableOperation.delete(entity);
try {
cloudTable.execute(deleteEntity);
logger.info("Successfully deleted location records with : " + entity.getPartitionKey());
} catch (StorageException e) {
e.printStackTrace();
}
}
} else {
logger.debug("No records to delete!");
}
//  throw new UnsupportedOperationException("AzureIotLocationDataDao Delete Operation not supported");
}