tuning oracle sql queries

Preface In the past decade, Oracle has become one of the world's most professional databases. For IT experts, it is to ensure that their company's productivity is improved by leveraging the powerful features of oracle. One of the most effective methods is to use ORACLE optimization. It has a lot of parameters and technologies to improve the performance of your

statement | 471 | 43803 | 979 (1) | 00:00:12 || 1 | table access by index rowid | T1 | 1 | 9 | 2 (0) | 00:00:01 || 2 | nested loops | 471 | 43803 | 979 (1) | 00:00:12 || * 3 | table access full | T1 | 471 | 39564 | 36 (0) | 00:00:01 || * 4 | index range scan | T1_IDX | 1 | 1 (0) | 00:00:01 |Bytes --------------------------------------------------------------------------------------Predicate Information (identified by operation id ):---------------------------------------------------3-filter ("A

, and parallel operators. Interested children's shoes can be clicked to view. In this article we introduce a series of sub-query statements, sub-query is generally the basis of our formation of complex queries ... Read the full text posted @2014-12-14 16:50 fingertip Flow Reading (1881) | Comments (6) Edit sql Server Tuning Series Basics (Summary of index Operat

Oracle Performance Tuning-Beyond OCP proficient Oracle Video tutorial Training 38Course IntroductionWind Brother Oracle Video tutorial , operating system optimization tuning, storage System optimization tuning experience, database

Label:Original: SQL Server Tuning series play Turn II (how to run with the aggregation joint hint (Hint) bootstrap statement)ObjectiveIn the previous article, we analyzed the usage of query hint as the first of the last play module of tuning series. Interested can click to view: SQL Server

read the output results to get all the information. Even the first page is enough to tell you where the remaining 10% of the Report is worth your attention. The statistical package of Oracle 9.2 contains the CPU and consumption time columns. Previously, in order to sort long-running SQL statements to the top, we had to enable "tracing", connect tracing files, and deliver them to the tkprof program for proc

does not exist in the table. (2) ' | | ' is a character join function. As with other functions, the index is deactivated. (3) ' + ' is a mathematical function. As with other mathematical functions, the index is deactivated. (4) The same index columns cannot be compared to each other, which will enable full table scanning.(+)A. If the number of records in a table that has more than 30% data is retrieved. Using indexes will have no significant efficiency gains.B. In certain situations, using an i

dbms_spd.flush_sql_plan_directive;SET Linesize 200COLUMN dir_id FORMAT A20COLUMN owner FORMAT A10COLUMN object_name FORMAT A10COLUMN col_name FORMAT A10SELECT To_char (d.directive_id) dir_id, O.owner, O.object_name,O.subobject_name Col_name,o.object_type, D.type, D.state, D.reasonFrom Dba_sql_plan_directives d,dba_sql_plan_dir_objects oWHERE d.directive_id=o.directive_idand O.owner = ' TEST 'ORDER by 1,2,3,4,5;No rows selectedSql>2. Performance feedback (performance Feedback)

Original: SQL Server Tuning Series Basics (subquery operations Summary)ObjectiveIn the previous articles, we introduced a series of descriptions of operators and the optimization methods and techniques for each operator. This includes a series of our common operators, including how to view execution plans, how several datasets are commonly used, how to join operators, and parallel operators. Interested chil

In the past decade,OracleIt has become one of the most professional databases in the world. For IT experts, IT is to ensure that their company's productivity is improved by leveraging the powerful features of Oracle. One of the most effective methods isOracle Optimization. It has a lot of parameters and technologies to improve the performance of your Oracle database. The following describes how to optimize

filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.The code is as follows:Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB having and AVG (SAL) >xxx7, usually, if the statement can avoid the use of subqueries, as far as po

resource utilization. First, you need to figure out how to test the resource usage of our servers when tuning the query. And I think of the set STATISTICS IO and set STATISTICS time SQL Server has long supported the two Transact-SQL commands for set STATISTICS IO and set STATISTICS time, but for some other reason, many DBAs (data for system administrators) ign