Advantages of lightweight I/O for smart large objects

Lightweight I/O provides some performance advantages, because the database server is not using the buffer pool.

Lightweight I/O provides the following advantages:
  • Transfers larger blocks of data in one I/O operation

    These I/O blocks can be as large as 60 kilobytes. But the bytes must be adjacent for the database server to transfer them in a single I/O operation.

  • Bypasses the overhead of the buffer pool when many pages are read
  • Prevents frequently accessed pages from being forced out of the buffer pool when many sequential pages are read for smart large objects

When you use lightweight I/O buffers for smart large objects, the database server might read several pages with one I/O operation. A single I/O operation reads in several smart-large-object pages, up to the size of an extent. For information about when to specify extent size, see Sbspace extents.


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