'Db file scattered read' is another common wait event. It is generated when Oracle reads multiple blocks from the disk to the non-sequential ("") Cache of the Buffer Cache. The maximum read value is
3. because the blocks that use full table scan and full index quick scan will be placed on the Buffer Cache to replace the nearest use end of the chain, sometimes using multiple Buffer Pools, it will be helpful to put these segments in the KEEP pool. (See Document 76374.1 Multiple Buffer Pools)
4. Using partitions can reduce the number of scanned data as partition pruning and limit the scanning subsets of segments.
5. finally, consider the amount of data contained in the longest accessed segments (by removing old and unwanted data from the database) or moving these segments to a new and faster disk, to reduce the IO response time.
(To be continued)