advanced oracle sql tuning

This is an online database http://www.dbonline.cn. Oracle expert tuning secret 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

query logical reads 20 times, pre-read 2 times, no physical read ..., and the table with the clustered index logic read 23 times, read 22 times! There are also statistical inaccuracies that result in physical reads 1 times! .... So it's a lot better than a stack table scan.Of course, in order to further analysis, in fact, the reason for the difference is simple: The table with the clustered index because of its stored structure (b-tree), so the logical IO is definitely 3 more, because from the

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

Oracle 10 Gb later optimizer supports two modes: Normal Mode and tuning mode. In most cases, the optimizer is in normal mode. The CBO-based Normal Mode only takes into account a small part of the Execution Plan set to select which execution plan, because it needs to be as short as possible, it is usually several seconds or milliseconds to parse the current SQL st

Resource Manager Lecture 41st: Chapter 10 -- Using Resource Manager Lecture 42nd: Chapter 11--sql statement Tuning Lecture 43rd: Chapter 11--sql statement Tuning Lecture 44th: Chapter 11--sql statement Tuning Lecture 45th: Chapte

, with a logical IO of 23 times, and read-ahead soared to 22 times.In comparison:The same query statement, the heap table query logical reads 20 times, pre-read 2 times, no physical read ..., and the table with the clustered index logic read 23 times, read 22 times! There are also statistical inaccuracies that result in physical reads 1 times! .... So it's a lot better than a stack table scan.Of course, in order to further analysis, in fact, the reason for the difference is simple: The table wit

modules. The first module focuses on the basic content of the master, a total of 7 articles to complete, covering a series of basic algorithms, the detailed analysis of how to view the execution plan, master Execution Plan optimization points, and a list of the everyday we usually write T-SQL statements will be applied operators. I believe that what you normallyWritten by T-... Read the full text posted @2015-01-20 21:57 fingertip flow reading (1571)

usually write T-SQL statements will apply the operator:SQL Server Tuning Series BasicsSQL Server Tuning Series Basics (Summary of common operators)SQL Server Tuning Series Basics (Union operator summary)SQL Server

Oracle Objective Over the past decade, Oracle has become one of the most professional databases in the world. For IT professionals, it is important to ensure that Oracle's powerful features are used to improve the productivity of their companies. One of the most effective ways to do this is through Oracle tuning. It h

| | 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 |--------------------------------------------------------------------------------------predicate information (identified by Operation ID):---------------------------------------------------3-filter ("A". ") object_name "like '%t1% ')4-access ("A". ") object_id "=" B "." OBJECT_ID ")Note------SQL