tuning oracle sql queries

L Preface The management of Oracle memory, up to 9ir2, is a very important aspect, mismanagement, will likely cause serious performance problems to the database. We'll take a step-by-step approach to all aspects of memory management. L Overview Oracle memory can be divided into the system global zone and the process global area in terms of shared and private, that is, the SGA and the PGA (process glob

Improves query efficiency by specifying an index for Oracle queries One 16 million data table-text message upstream table tbl_sms_moStructure:Create Table tbl_sms_mo(Sms_id number,Mo_id varchar2 (50 ),Mobile varchar2 (11 ),Spnumber varchar2 (20 ),Message varchar2 (150 ),Trade_code varchar2 (20 ),Link_id varchar2 (50 ),Gateway_id number,Gateway_port number,Mo_time date default sysdate);Create index idx_mo_da

request timed out" error message with the code 1222: Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->-- Session BSET lock_timeout 3000SELECT * from Orders WHERE OrderID=10248--SET lock_timeout-1 Execution Result:MSG 1222, Level 16, State 51, line 3rdThe lock request time-out period has been exceeded.Statement has been terminated.-------------------------------------------------------------------------------------------According

read times. The ways to refine each statement are:Check Optimizer statistics，Check the interpretation plan for the most efficient access pathMeasuringtry to replace SQL constructs, and test for possible new indexes, manifested views, and partitions. Test the performance of the entire application using the optimized SQL statement. Is overall performance improved? The method is reliable, but somewhat dilator

Tags: table rtu pad ACL pos LSP Oracle Database Err BSP 1 Status queries Start state SQL Statement Results Nomount Select status from V$instance; STARTED Select Open_mode from V$database; ERROR at line 1:Ora-01507:database not mounted Mount Select status from V$instance;

:1, the size of the table is more than 2GB.2. The table contains historical data, and new data is added to the new partition.2.2 Advantages and disadvantages of table partitioningTable partitioning has the following advantages:1. Improve query performance: Queries on partitioned objects can search only the partitions they care about and improve the retrieval speed.2. Enhanced usability: If one partition of the table fails, the data of the table in oth

--======================================= --The adjustment and optimization of shared pool (Sharedpool tuning) --======================================= Shared pool is the most critical memory fragment in the SGA, which consists primarily of the library cache (shared SQL and Pl/sql) and the data dictionary cache. Where the function of the library cache is to sav

PL/SQL "ORA-14551: cannot perform DML operations in queries" solved the environment Oracle 11.2.0 + SQL Plus problem by writing a function according to the following requirements. in the emp table, the total number of employees whose salaries are lower than the average wage plus 200 is returned. An updated operation in

can automatically optimize queries based on the where clause, it is still necessary for you to understand the working principle of the "query optimizer". If not, sometimes the query optimizer does not perform quick queries according to your intention.In the query and analysis phase, the query optimizer checks each stage of the query and determines whether the data volume to be scanned is useful. If a phase

Transferred from: http://blog.sqlauthority.com/2010/05/14/sql-server-find-most-expensive-queries-using-dmv/The title of this post was what I can express here for this Quick blog post. I was asked in recent Query tuning consultation project, if I can share my script which I use to figure out which is the M OST expensive querie