Under the full recovery model or bulk-logged recovery model, if the transaction log has not been backed up recently, backup might be what is preventing log truncation.

在完整恢复模式或大容量日志恢复模式下，如果最近尚未备份事务日志，则请立即进行备份以免发生日志截断。

youdao

A pure log backup contains only transaction log records for an interval, without any bulk changes.

纯日志备份只包含某个时间段的事务日志记录，不包括任何批量更改。

youdao