Multiblock Reads

There’s plenty more I could talk about regarding the CBO CPU costing model and system statistics but I’ll make this my final little comment on this subject for now.   As previously discussed, the CPU costing model basically takes the time it takes to perform the all necessary I/O related activities and all the time it takes to [...]

One of the advantages of system statistics and the CPU costing model is in how the CBO deals with multiblock reads and the impact of the db_file_multiblock_read_count parameter. When performing a full table (or fast full index) scan, the CBO needs to determine just how many multiblock read operations are likely to be performed so the associated operation can [...]