A massdelete operates much more efficiently and writes considerably less log information.
mass delete执行起来要高效得多,并且要写的日志信息也更少一些。
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If all rows in a table are deleted (known as a massdelete), all segments become immediately available for reuse at the COMMIT point, without requiring the REORG utility to be executed.
Since those triggered actions are typically one or more insert, UPDATE, or DELETE statements, the overhead of triggers can be substantial in a mass insert operation.