how to optimize sql query using execution plan

1) Clear the cache plan first, pay attention to the production environment use this statement with caution!DBCC FREEPROCCACHE2) re-execute the query, system use, etc.3) Find the longest statement time, you may need to perform multiple times to determine the average time, the code is as follows:SELECT creation_time N ' statement compilation time ', Last_execution_time N ' last

on v _ $ sesstat to plustrace; authorization successful. SQL> grant select on v _ $ statname to plustrace; authorization successful. SQL> grant select on v _ $ mystat to plustrace; authorization successful. SQL> grant plustrace to dba with admin option; authorization successful. SQL> grant plustrace to HR; authorizati

Dba_hist_ SQL _plan is an important view for querying the execution plan of oraclesql. I would like to express my gratitude for the help of elders who have prepared this article. The applicable oracle database version is oracle 10 Gb or later. This view is important because one column in this view is not found in the awrsqrpt report. This column is the filter_pre

A.account_number is not NULLand c.account_no like ' 0% 'GROUP BY D.explanation,--Financial institution identification codeC.account_no,--Trading accountA.batchentrydate,--Date of occurrenceC.currencycode,--Currencyc.ccyledgerbalance--System Agency Code Observation and analysis of its implementation plan, seemingly there is no problem, because Df_acmov_today (200W or so) is emptied every day, no index, full table scan, Nestloops also normal. However

Article 1: how to optimize slow query SQL statements in MySQL56-Introduction to slow logs: in actual log analysis, there are usually a large number of slow logs, at the same time, there will be a large number of records for the same query. here we need to find the most problematic and optimized log in the actual log an

Oracle 11g how to clear the execution plan of an SQL statement in the share pool, 11 gpool In the past, if the execution plan was slow due to binding snoop on a 10 Gb database, you wanted to clear the execution

At Oracle 9i or above, Oracle sometimes chooses to convert the B-Tree index to BITMAP for SQL Execution, resulting in an extremely bad execution plan. The conversion is determined by the hidden parameter _ B _tree_bitmap_plans. If this parameter is set to true, it is converted. Otherwise, no conversion is performed. In

table t;Sql> Flashback table T to before drop;-----Exception Execution PlanSql> select * from t where object_id=19;Execution Plan----------------------------------------------------------Plan Hash value:329240726--------------------------------------------------------------

Three-day Dragon Boat Festival holiday, I learned jruby and groovy. At last I thought groovy was easy to use. Using groovy is a bit like writing basic, and there are no more rules like Java. During development, code is used to describe the execution logic, rather than writing a large number of classes that comply with Java "patterns" to implement certain logic functions. Groovy gives me the feeling that the

plustrace; authorization successful. SQL> grant select on V _ $ mystat to plustrace; authorization successful. SQL> grant plustrace to DBA with admin option; authorization successful. SQL> grant plustrace to HR; authorization successful. SQL> exit After authorization, log on to the Oracle common user HR: Open autotrac

How to clear the execution plan of an SQL statement in the share pool in Oracle 11g In the past, if the execution plan was slow due to binding snoop on Oracle 10 Gb database, you wanted to clear the execution

The next article is to record their own blind spots, but also reveal their own development process (may not be developed, can only be said to be blind). Of course, some blind spots are also in the process of work and exploration slowly some, now also willing to carry forward the dedication of the blog park, to come out and share with you.Open the door and go straight into the question.Have you ever had the same doubts as me when looking at the execution