The writes will not cross extent boundaries so if you use AUTOALLOCATE for extent management and it starts with 64K extents then that is all that will be returned in a single read. Once the extent size reaches 1M or larger then it's not an issue. Keith > I have always been a little humored by this parameter. > db_file_multiblock_read_count attempts to specify a maximum value, as does > the MBRC collected by system stats. However, that does not determine how > many blocks are actually scooped up in a multiblock pass. One good example > is to set event 10046 on a full table scan with waits (level 8 or 12) and > look for db file scattered read waits, which will have the number of blocks > read during the wait. -- //www.freelists.org/webpage/oracle-l