We know that,Oracle DatabaseEach process in to complete a specific task or a group of tasks, each process will allocate internal memory PGA memory) to complete its tasks. Oracle instances mainly have three types of processes:Server processBackground
This article summarizes Oracle transactions, introduces transaction features, transaction management, transaction reads, and provides examples. For more information, see this article.
This article summarizes Oracle transactions, introduces
Characteristics of Oracle TransactionsACID, an abbreviation for the four basic elements that a database transaction performs correctly. Contains: atomicity (atomicity), consistency (consistency), isolation (isolation), persistence (durability). A
An error was encountered today when adding a field to a temporary table: ORA-14450 attempt to access a transactional temp table already inuseThe following experiment simulates the reasons why the 2 temporary tables were used improperly to report ora-
Oracle temporary table optimization query speed -- Aspx. CN technical data center operating system program design graphics image media animation office software database certification trainingWeb Development Network Principles network management
ACID: Atomic, Consistent, Isolated, Durable
A storage program provides an excellent mechanism to define, encapsulate, and manage transactions.
1. MySQL transaction support
1) MySQL transaction support is not bound to the MySQL server itself, but
First, we recommend that you execute showprocesslist to check whether the table (database object) to be operated is in the lock status 1if (unlocked) when you perform DDL operations on the MySQL table) 2 {3 execute DDL statement 4} else5 {6 think
MySQL introduced metadatalock in 5.5. as the name suggests, metadatalock is not designed to protect data in tables, but to protect databaseobjects (database objects. Including table structure, schema, stored procedures, functions, triggers, and
This error is also caused by operations on a table, such as update and truncate. In addition, if the transaction is not committed, other operations may also cause this exception.
ORA-00054 resource busy and acquire with Nowait specified
Cause:
This blog is prepared in two parts for a detailed introduction to MySQL (based on MySQL 5.6) in metadata lock,I. Description of metadata locking in official documentation (5.6)8.11.4 Metadata Lockingmysql uses Metadata locking to manage concurrent
1. Preface
At present, all use Oracle as database support platform application, most of the data volume of the system, that is, table data volume is generally in millions above data volume.
Of course it's a good choice to create partitions in Oracle,
oracle| temporary table | speed | optimization
1. Preface
At present, all use Oracle as database support platform application, most of the data volume of the system, that is, table data volume is generally in millions above data volume. Of course it'
I. OverviewUndo saves the old data. Example. You changed a record to change the A-column ABC to def. Then undo keeps ABC. There are two purposes: 1. Assume that your transaction is not committed. But already the column a changes, then others read
Http://www.cnblogs.com/quanweiru/archive/2012/11/09/2762223.html 1,for update and for update nowait differences: First of all, if only Select,Oracle will not add any lock, that is, Oracle to Select read the data there is no limit, although it is
? Describes locking mechanisms and how Oracle manages data concurrency processing? Using SQL to manage Data? identify and manage PL/SQL Objects? Describe triggers and trigger events? Monitoring and resolving locking conflicts
Working with
Original: http://dev.mysql.com/doc/refman/5.5/en/innodb-next-key-locking.html14.5.2.5 avoiding the Phantom problem Using Next-key LockingThe so-called Phantom problem occurs within a transaction when the same query produces different sets of rows at
(1)-v$session_waitThis is a critical view of looking for performance bottlenecks. It provides any case where the session is currently waiting in the database (if the session is currently not doing anything, it shows its last wait event). When there
Importnew Note: This article is one of the importnew compiled by the Java Surface Test series. You can view the full range of Java interviews from here.
Q. How do I configure hibernate?A The configuration class uses the Config Hibernate.cfg.xml
When updating a table, Oracle will add a tmlock to the table before submission to ensure that the table structure will not change. At this time, if another session executes alter on this table
When updating a table, Oracle will add a tmlock to the
Among the many Oracle problems, the most important one is the buffer busy wait (buffer busy wait) event.
Buffer busy waiting is the most common phenomenon in the I/O-bound Oracle system, especially in the first five busy (sequential/distributed)
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