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What are query optimization techniques in Oracle?

Jeremy Anderson

What are query optimization techniques in Oracle?

Here are the query optimization techniques in oracle which you could use to performance tune your Oracle database:

  • Start with the System Level SQL tuning.
  • Rewrite complex subqueries with temporary tables.
  • Index all predicates.
  • Use Inner Joins instead of Outer Joins.
  • Use CLOB/BLOB columns at end statements.

How do I make my Oracle query run faster?

Best Practices for Query Tuning in Oracle

  1. Best Practice 1: Clarify Goals.
  2. Best Practice 2: Identify High-Impact SQL Statements.
  3. Best Practice 3: Identify Your Execution Plan.
  4. Best Practice 4: Avoid Large Scans.
  5. Best Practice 5: Optimize SELECTs.
  6. Best Practice 6: Use a Third-Party Tool.

How do you optimize a query?

SQL Query Optimization: How to Tune Performance of SQL Queries

  1. Tip 4: Use wildcards at the end of a phrase only.
  2. Tip 5: Avoid too many JOINs.
  3. Tip 6: Avoid using SELECT DISTINCT.
  4. Tip 7: Use SELECT fields instead of SELECT *
  5. Tip 8: Use TOP to sample query results.
  6. Tip 9: Run the query during off-peak hours.

How do you optimize a query in PL SQL?

Avoiding CPU Overhead in PL/SQL Code

  1. Make SQL Statements as Efficient as Possible.
  2. Make Function Calls as Efficient as Possible.
  3. Make Loops as Efficient as Possible.
  4. Don’t Duplicate Built-in String Functions.
  5. Reorder Conditional Tests to Put the Least Expensive First.
  6. Minimize Datatype Conversions.

How do I slow a running query in Oracle?

How to Tune PL/SQL Performance with Oracle SQL Profiler

  1. Examine causes for slow-running queries and bad performance.
  2. Monitor query performance using the Oracle explain plan.
  3. Search for database bottlenecks and analyze its impact on database performance.
  4. Manage loads increased on database.

Which cursor is faster implicit or explicit?

implicit cursors
The short answer is that implicit cursors are faster and result in much neater code so there are very few cases where you need to resort to explicit cursors.