在使用Apache Iceberg进行数据写入时，常常会遇到一些性能问题，特别是当数据需要写入到多个分区时。本文将通过一个实际案例，探讨如何优化Iceberg表的分区写入策略，提高数据写入的效率。问题描述假设我们有一个包含大量广告曝光数据的数据集，需要将其写入到Iceberg表中。我们的目标是根据exposure_id、event_date和advertising_id进行分区，同时确保每个分区内数据是按advertising_id和timestamp排序的。然而，当尝试写入多个分区时，遇到了以下错误：Caused by: java.lang.IllegalStateException: Incoming records violate the writer assumption that records are clustered by spec and by partition within each spec. Either cluster the incoming records or switch to fanout writers. Encountered records that belong to already closed files: partition 'exposure_id=10/event_date=2024-06-28' in spec [ 1000: exposure_id: identity(13) 1001: event_dat