TruTek

There is a myth that having multiple extents in tables and indexes hurts performance in Oracle. Purportedly, having only a single extent (or at least a small number of extents) for every table and index will somehow help optimize SQL statement performance. This assertion is mainly based on the idea that packing all data into a single extent optimizes I/O performance by having all database blocks contiguous to one another, thus minimizing disk head movement, or something like that.

Also, having all data packed into a single extent eliminates the vague bogeyman threat of tablespace fragmentation, which is also supposed to be bad for SQL statement performance, somehow.

Last, packing all data into a single extent is also supposed to make a database easier to manage. This is not an issue surrounding database performance, but database administrator performance, presumably.

As it turns out, all of these assertions are completely incorrect. Let's dissect each one of them in turn.

When asked to "Select a payment method" for your free download, choose "Print and Call". Your download code will be e-mailed to you after we authorize it. International customers should enter TruTek's address as the shipping address and enter their real shipping address in the Special Instructions field on the payment screen.