Lightweight I/O for smart large objects

Instead of using the buffer pool, the administrator and programmer have the option to use lightweight I/O. Lightweight I/O operations use private buffers in the session pool of the virtual portion of shared memory.

By default, smart large objects pass through the buffer pool in the resident portion of shared memory. Although smart large objects have lower priority than other data, the buffer pool can become full when an application accesses many smart large objects. A single application can fill the buffer pool with smart large objects and leave little room for data that other applications might need. In addition, when the database server performs scans of many pages into the buffer pool, the overhead and contention associated with checking individual pages in and out might become a bottleneck.

Important: Use private buffers only when you read or write smart large objects in read or write operations greater than 8080 bytes and you seldom access them. That is, if you have infrequent read or write function calls that read large amounts of data in a single function invocation, lightweight I/O can improve I/O performance.

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