oracle performance tuning basics

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 feedb

15 useful MySQL/MariaDB performance tuning and Optimization Techniques MySQL is a powerful open-source Relational Database Management System (RDBMS ). It was released in 1995 (20 years ago ). It uses Structured Query Language (SQL), which may be the most popular choice in database content management. The latest MySQL version is 5.6.25, which was released on July 25, May 29, 2015. An interesting fact about M

trivial matter. If reference is included, that is, object instance = new object (); that is, 12 bytes, 4 bytes indicates the space occupied by the reference. Class student { Int nmber; Boolean isgood; Object teacher; } Size: 8 (empty object) + 4 (INT size) + 1 (Boolean size) + 4 (size referenced by teacher) = 17 bytes, in Java, the object memory is allocated by an integer multiple of 8 and is allocated to 24 in sequence. The object size is 24 bytes. In addition, references are the catego

be reported as ' too many connections ' error. For the value setting of wait_timeout, it should be judged according to the operation condition of the system.# After the system has been running for a period of time, you can view the current system's connection status through the show Processlist command, if you find a large number of sleep status of the connection process, the parameter setting is too large,# you can make the appropriate adjustments smaller. To set Interactive_timeout and wait_t

value setting of wait_timeout, it should be judged according to the operation condition of the system.# After the system has been running for a period of time, you can view the current system's connection status through the show Processlist command, if you find a large number of sleep status of the connection process, the parameter setting is too large,# you can make the appropriate adjustments smaller. To set Interactive_timeout and wait_timeout at the same time will not take effect.[Mysqldump

more information: Open source distributed database middleware mycat:http://blog.oldboyedu.com/mysql-mycat/Mycat: Open Source distributed database middleware: http://www.csdn.net/article/2015-07-16/2825228 Mongodb I've heard about it a few years ago, just know it's a nosql database, knowing that the storage format is JSON and is a file database. MongoDB supports sharding: Concrete implementation: http://my.oschina.net/ydsakyclguozi/blog/268377 PostgreSQL

When it is determined that application performance problems can be attributed to one or several time-consuming statements, tuning these statements is the responsibility of the database administrator or database application developer. Statement tuning is one of the essential skills for dealing with databases.When you face a "problem" statement, how should you anal

One of the practical skills that can greatly improve the performance of SQL TUNING optimization. When we perform SQL optimization, we often encounter the need to sort a large number of datasets and then retrieve the first part of the results from the sorted set. In this case, when we write SQL statements according to the general idea, the system first reads and filters all sets, then sorts them, and then ex

Original addressMySQL is a powerful open source relational database management system (RDBMS). It was posted on 1995 (20 ago). It uses Structured Query Language (SQL), which may be the most popular choice in database content management. The latest MySQL version is 5.6.25, released on May 29, 2015.An interesting fact about MySQL is that its name comes from the daughter "My" of Michael Widenius (the founder of MySQL). Although there are many interesting rumors about MySQL, this article is mainly t

Tags: mysql, mariadb1. Performance1) Performance improvementMySQL5.7 provides more consistent linear performance and scalability on systems that support multi-processor and highly concurrent CPU threads. The key to achieving this is to eliminate InnoDB kernel contention and mutex locking through the concurrency of the efficiency of the Oracle InnoDB storage engin

performance, and to control their sum within the value specified by the Sga_target. Once you assign a value to Sga_target (the default is 0, that is, ASMM is not started), the ASMM feature is started automatically.iii. Oracle Memory tuning approachWhen a performance problem arises in the production environment of a pr

Oracle SQL Tuning Oracle's SQL tuning is a complex topic, and even a whole book is needed to introduce the nuances of Oracle SQL tuning. But there are some basic rules that every Oracle DBA needs to follow, and these rules can im

, please look down. First, ask yourself how big the difference is between "Empty" and "null" (if it's int, that's 0 and null)? If you feel that there is no difference between them, then you should not use NULL. (Do you know?) In Oracle, NULL and Empty strings are the same! Do not assume that NULL does not require space, that it requires additional space, and that your program will be more complex when you compare it. Of course, this is not to say that

1m-2m size, and then set it individually on demand in each session. 4, Read_rnd_buffer_size For sorting and order by operations, it is best to set it to 1M and then set it as a session variable to a larger value in the session. (v) Slow query log A slow query log is a useful feature of MySQL. 1, Log_slow_queries MySQL parameter in the log_slow_queries parameter set it in the My.cnf file, set it to on, by default, MySQL will put the file into the data directory, the file is named "Hostname-slow.

SQL Optimization Oracle SQL optimization is a complex topic, and even requires the entire book to introduce the nuances of Oracle SQL optimization. However, there are some basic rules that every Oracle DBA must follow. These rules can improve the performance of their systems. The goal of SQL optimization is simple: . E

The SQL Tuning toolset (SQL Tuning set,sts) is an integral part of the Oracle 10g SQL Tuning Advisor feature. Each tuning toolset contains one or several SQL statements, as well as the contextual information needed to properly interpret them. SQL

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 analysis and tuning. Background knowledge Main methods of performance analysis Monitoring: Monitoring is a common way to view the run-time behavior of an application. There are often multiple views (view) that display CPU usage, memory usage, thread state, and other useful information in real time, so that users can quickly discover the key to the

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 datab

Label:MySQL is a powerful open source relational database management system (RDBMS). It was posted on 1995 (20 ago). It uses Structured Query Language (SQL), which may be the most popular choice in database content management. The latest MySQL version is 5.6.25, released on May 29, 2015. An interesting fact about MySQL is that its name comes from the daughter "My" of Michael Widenius (the founder of MySQL). Although there are many interesting rumors about MySQL, this article is mainly to show yo