oracle sql tuning tips

. Careful use of large temporary tables and other large table connection query and modification, reduce the system table burden, because this operation will be in one statement multiple times the system table of tempdb. d) Rational use of the algorithm: based on the SQL optimization techniques mentioned above and the SQL optimization content in the ASE Tuning ma

Tags: tabs Other applications ABS SSE contains increased data process structure understandingThe parameters of the tuning function in the Oracle database system are called initialization parameters, and the database administrator needs to properly adjust these initialization parameters to optimize the Oracle system according to the actual situation.1 introduction

. The customer provided an AWR report during peak hours. After careful analysis, it was found that it was a high-CPU-consuming SQL statement, which only took 85% of the CPU, this gives us an in-depth understanding of SQL optimization. We have also done some DB optimization before, basically through analysis tables, index creation, parameter adjustment, PATCH, and so on. However, this time, it lasted for a w

Kernel.shmmaxKernel.shmmax = 2147483648[Email protected] ~]# sysctl-p[Email protected] ~]# su-oracle[Email protected] ~]$ sqlplus '/as sysdba 'Sql*plus:release 10.2.0.1.0-production on Mon Nov 16 05:50:00 2009Copyright (c) 1982, 2005, Oracle. All rights reserved.Connected to:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0-productionWith the partitionin

Io is very relevant, when the free buffer waiting in the v$session_wait of the entry is very small or not, Explain the DBWR process of your system will be enough, do not need to adjust, there are many items of free buffer wait, your system must feel very slow, then your DBWR is not enough, the resulting wio has become your database performance bottlenecks, the solution is as follows: A.1 to increase the write process while adjusting the db_block_lru_latches parameters Example: Modify or add the

of disk sorting will be greatly increased. This is mainly because at the end of the month, users will make statistics on the transaction data for the month. So at the beginning of the month, because of the number of transactions, so there will be more disk sorting occurs. In this case, it is necessary for the database administrator to adjust the relevant parameters. However, this adjustment is a temporary adjustment, until the cycle has passed, still need to transfer the parameters back. Only i

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

the deterioration of performance is a variety of factors, and sometimes the results of the performance degradation caused by multiple elements, this requires the database administrator has a more comprehensive computer knowledge, can be sensitive to the impact of the database performance of the main reason. In addition, good database management tools are also important for optimizing database performance. Database performance optimization tools commonly used in

Document directory Preliminary steps Using bind variables There are several relatively easy steps you can take to improve performance. From the user's perspective, one of the most frequently used interfaces with a database involves SQL statements, so getting a handle on them is a good place to start, in terms of being able to see an immediate improvement. -->Oracle

. server.2005. Technical Insider "series Conclusion This article first to this bar, short, easy to understand, this article mainly introduces the query plan of the joint operators, the next we analyze SQL Server parallel operations, in multicore hyper-threading gathered today, see SQL How server uses parallel operations to maximize the use of existing hardware resources to improve performance, is inte

It is troublesome to optimize an SQL statement before Oracle 10 Gb. However, the SQL Tuning Advisor tool launched in Oracle 10 Gb can greatly reduce the workload of SQL optimization, however, to use

Tag: Time Condition number column arch OSI user CTE codeIn section 1.5 of the SQL Tuning Basics Overview 05-oracle Index Type and introduction, several "Common index execution plans" are mentioned: Index full Scan: Fully scanned indexes, block read, orderedIndex range Scan: Range sweep of indexIndex fast full Scan: Fast all scans of indexes, multiple rea

In Oracle database systems, the parameters that play the role of tuning are called initialization parameters, which are recorded in the Initsid.ora file in Oracle 8i and previous versions, while Oracle 9i/10g/ These parameters are recorded in the Spfilesid.ora binary in 11gBasic parameters: A set of adjustable paramete

Oracle Adjusts Oracle's competition One of the benefits of Oracle is that it manages the free space in each table space. Oracle handles the space management of tables and indexes so that we don't have to understand the internal workings of Oracle's tables and indexes. However, for an experienced Oracle

The Association of SQL tuning and shared pool structures introduces three types of computer resources that affect performance: Memory, CPU, and I/O. By adjusting SGA and PGA to make full use of physical MEMORY, making full use of CPU through parallel processing, and making full use of Hard Disk processing power by adjusting I/O distribution. Server process and PGA are "two grasshoppers on one rope", so sp a

Tags: Practice login 16px between multiple connect shut down database SQL business logic　　The end of 2016 was the stage where I learned to understand the entire front end, backend, and database programming. During the practice programming process, notice that there is a scene between the server and the database: Start linking Database SQL--- $loginin =mysql_connect ("192.168.10.253:3306", "root", "123456");

oracle| Data | database | Performance Oracle is a high-performance database software. The user can adjust the parameters to achieve the optimization of performance. Performance optimization is mainly divided into two parts: first, the database administrator through the adjustment of system parameters to achieve the goal of optimization, the second is the development of the application of the optimization to

for media recovery.D.unused indicates that the log was never written, could have just been added, or was reset after resetlogs.6. Delete the old log groupsql> ALTER DATABASE drop logfile Group 1;sql> ALTER DATABASE drop logfile Group 2;sql> ALTER DATABASE drop logfile Group 3;7. Delete the Redolog log file under the operating systemMV/U01/ORACLE/ORADATA/ORCL/RED

-------------------------------------------------------------------------| Id | Operation | Name | Cost (%CPU) |-------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 4 (0) || 1 | TABLE ACCESS by GLOBAL INDEX rowid| SALES | 4 (0) || 2 | INDEX RANGE SCAN | Index_qu_sold | 3 (0) |-------------------------------------------------------------------------9 Rows selectedSql> alter session Set "_use_nosegment_indexes" =true;Session altered.Sql> CREATE index

nothing is perfect.The cost of the Begin Tran is that all the resources locked by the SQL statements cannot be released until the commit is committed before committing.It can be seen that if the BEGIN TRAN too many SQL statements, the performance of the database is poor. Before this large transaction commits, it is bound to block other statements, resulting in many blocks.The principle of the BEGIN Tran is