Oracle SQL Performance Tuning - From Scratch To Tuner

Explore the module on index types, including beta, bitmap, function based, index organized tables, cluster, and composite indexes, and learn the purpose and advantages of each.

Learn how an index acts as a pointer to data blocks, enabling direct access and avoiding full table scans for selective queries; understand when full table scans are faster.

Understand beta (b-tree) indexes, their root, branch, and leaf structure, when to use them for high distinct value columns, and how simple versus composite indexes affect query scans.

Oracle's bitmap index optimizes queries on low-cardinality columns by converting values into bitmaps of zeros and ones, enabling fast bitwise operations and space-efficient data warehouse performance.

Learn to create a function based index on email using lower(email) to improve index usage and avoid full table scans, and understand limitations when applying different functions.

Explore index organized tables stored in a B3 structure where data and index share storage, enabling fast retrieval via the primary key and including non-key columns, with creation constraints.

Explore cluster indexes that cover multiple tables sharing a common column. Create a cluster and a cluster index on the shared department column, and see how it enables efficient queries.

Learn how composite indexes on two or more columns limit scanned rows and speed queries, illustrated by department and salary example, and note that too many columns can slow performance.

Explore Oracle SQL performance tuning by examining bitmap index, function-based index, index-organized tables, cluster index, and composite index.

Examine the Oracle SQL optimizers, rule-based and cost-based, and how they produce an execution plan. Learn how statistics, transformer, estimator, and plan generator choose the lowest-cost query path.

Compare how the rule based optimizer (RBO) uses access path ranks to select an execution plan. Contrast RBO with the cost based optimizer (CBO) and show why CBO improves performance.

The cost based optimizer uses statistics from tables, indexes, columns, and the system to estimate costs, tries many execution plans, and selects the cheapest one, adapting to changing data distribution.

Understand how the optimizer generates an execution plan for queries, comparing RPO and CBO; RPO selects among 15 access paths by lowest strength, while CBO optimizes IO, CPU, and memory.

Define what an execution plan is, how to read and generate it with explain plan and the DBMS_EXPLAIN package, and understand its components, cost, and rows.

Discover how to read Oracle execution plans by understanding components (operation, name, rows, cost, time), access predicates, filter predicates, index scans, joins, and cardinality.

Master the order of operation in the Oracle SQL execution plan by tracing parent-child relationships and indentation. Learn two methods to read the plan and identify inner and outer operations.

Explore how an execution plan outlines the steps to run a sql statement, compare expected and actual plans with dbms_xplan, and see how cardinality, access methods, and joins influence performance.

Explore how Oracle uses access methods to fetch data: full table scans, index scans (by, unique, range, skip), and bitmap indexes, with practical guidance.

learn how joins connect two tables using a common condition, compare nested loop, hash, and sort-merge joins, and optimize with indexes, predicates, and execution plans.

Explore how Oracle statistics and histograms influence query optimization, covering cardinality, distinct values, densities, and frequency and height-balanced histograms.

Learn a fundamental approach to query tuning by using selective where clauses and indexes to avoid full table scans and optimize joins with primary key and foreign key relationships.

Explore using optimizer hints to steer execution plans, manage baselines, and lock in the best plan based on data distribution, even when statistics are stale.

Explore practical Oracle SQL performance tuning with scripts and case studies, covering execution time, cache and disk IO metrics, execution plans, and how to read and reuse past results.