Optimization Methods
When the query optimizer chooses a query plan, it takes into account the methods available to it. It must decide how to access the table, the order in which tables should be joined, and what methods to use to carry out the join. In this section we consider each of these alternatives.
Note that optimizers may also consider data location, especially in shared-nothing environments. For example, can joins be performed locally (colocated joins), or does data need to be moved between nodes? The issues associated with colocated joins and data shipping are explored in “Massively Parallel Processor (MPP) Systems” on page 32.
Table Access
The simplest way of retrieving information from a table is to read the table data in its entirety. ...
Get Configuring and Tuning Databases on the Solaris™ Platform now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
