How do I disable a SQL baseline?

How do I enable a SQL baseline?

To enable baseline usage, optimizer_use_sql_plan_baselines must be true. Consider a baseline for the plan with the lowest cost or best elapsed time. The optimizer will choose the lowest cost accepted plan but will give preference to a fixed plan.

What is a SQL baseline?

Defined, a SQL Plan Baseline is a set of one or more “accepted” plans that contain hints, the plan hash value and other plan related data. In addition to the actual baseline, Oracle also maintains a SQL Plan History. … A statement has had three different execution plans generated.

How do I delete an execution plan in Oracle?

Flush Bad SQL Plan from Shared Pool

  1. 1) FIND ADDRESS AND HASH_VALUE OF SQL_ID SQL> select ADDRESS, HASH_VALUE from V$SQLAREA where SQL_ID like ‘7yc%’; ADDRESS HASH_VALUE —————- ———- 000000085FD77CF0 808321886.

How do I check if a SQL baseline is used?

Displaying SQL Baseline Plans

  1. run a statement that uses an index and check the plan.
  2. create a Baseline on the statement using the index (using my create_baseline. …
  3. check the hints stored with the baseline (using my baselines_hints. …
  4. run the statement again and check the real plan to see that the Baseline was used.
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How do I load a SQL baseline from AWR?

How to load sql plan baseline from AWR

  2. BEGIN. DBMS_SQLTUNE. DROP_SQLSET (sqlset_name => ‘STS_f9948h4y2aa22’); …
  3. BEGIN. DBMS_SQLTUNE.CREATE_SQLSET( sqlset_name => ‘STS_f9948h4y2aa22’, …
  4. DECLARE. cur sys_refcursor; …
  5. SELECT. first_load_time , …
  6. DECLARE. my_plans pls_integer;

What is the difference between SQL baseline and SQL profile?

Think of it this way: SQL profiles give information to the optimizer to help select the best plan but don’t force the optimizer to select any specific plan. SQL plan baselines limit the optimizer plan selection to a set of accepted plans.

What are the different ways in which PL SQL can run?

You can run a procedure or function interactively by: Using an Oracle tool, such as SQL*Plus. Calling it explicitly in the code of a database application, such as an Oracle Forms or precompiler application. Calling it explicitly in the code of another procedure or trigger.

How do I force a plan in Oracle?

Answer: Oracle provides many ways to force an execution plan:

  1. Stored Outlines: Stored outlines will same an existing execution plan and force it to be used. …
  2. SQL Hints: Oracle hints are optimizer directives that can be used to force Oracle to always use the same execution plan for a SQL statement.

What is Optimizer_adaptive_plans?


Adaptive plans are execution plans built with alternative choices that are decided at run time based on statistics collected as the query executes.

What is Coe_xfr_sql_profile SQL in Oracle?

The coe_xfr_sql_profile. sql script generates another script that, in turn, contains the commands to create a manual custom SQL Profile out of a known plan that resides in RAM (library cache) or from the AWR dba_hist_sqlplan table.

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How do I flush a SQL ID?

How to flush a sql statement from shared pool

  1. Get the address and hash_value of the sql_id:
  2. Now purge the sql statement. exec DBMS_SHARED_POOL.PURGE (‘ADDRESS,HASH_VALUE’,’C’); exec DBMS_SHARED_POOL.PURGE (‘0000000693E4C268,2515443712′,’C’); PL/SQL procedure successfully completed.

How can I change SQL plan in Oracle?

Use the SQL statement below for the purpose:

  1. Create a test table and find good / bad SQL plans.
  2. Step -1: Fetch Bad Execution Plan Details.
  3. Step-2: Baseline the Bad SQL Explain Plan.
  4. Step-3: Disable the bad SQL Plan.
  5. Step-4: Fetch Modified SQL Plan Details.
  6. Step-5: Replace Execution Plan with Modified version.