Understanding the results of Execute Explain Plan in Oracle SQL Developer

Question

I\'m trying to optimize a query but don\'t quite understand some of the information returned from Explain Plan. Can anyone tell me the significance of the O

Answer 1

FULL is probably referring to a full table scan, which means that no indexes are in use. This is usually indicating that something is wrong, unless the query is supposed to use all the rows in a table.

Cost is a number that signals the sum of the different loads, processor, memory, disk, IO, and high numbers are typically bad. The numbers are added up when moving to the root of the plan, and each branch should be examined to locate the bottlenecks.

You may also want to query v$sql and v$session to get statistics about SQL statements, and this will have detailed metrics for all kind of resources, timings and executions.