Memory Usage

select * from sys.x$memory_global_total

select * from sys.x$memory_by_user_by_current_bytes

select * from sys.x$memory_by_host_by_current_bytes

High Cost SQL Statements

select * from sys.x$statement_analysis

select * from sys.x$statements_with_runtimes_in_95th_percentile

select * from sys.statements_with_temp_tables

select * from sys.statements_with_sorting

select * from sys.statements_with_full_table_scans

select * from sys.statements_with_errors_or_warnings

Database Scheme Statics

select * from sys.schema_unused_indexes