Recommended 10 commonly used Retention usages, welcome to download!

Retention annotation The Retention (retention) annotation indicates that this type of annotation will be retained to that stage. There are three values: 1.RetentionPolicy.SOURCE - This type of Annotations is only retained at the source code level and is compiled at compile time. Will be ignored 2.RetentionPolicy.CLASS - Annotations of this type are retained during compilation and exist in the class file, but the JVM will ignore them 3.RetentionPolicy.RUNTIME - Annotations of this type will be retained by the JVM, so they Can be read and used by the JVM or other code using the reflection mechanism at runtime. Example 5 demonstrates the declaration of RetentionPolicy.RUNTIME: Example 1 of Java annotation: @Retention(RetentionPolicy.RUNTIME) public @interface Test_Retention

1. Introduction to Retention, Documented, and Inherited of Java annotations

Introduction: This article mainly introduces the introduction of Retention, Documented, and Inherited annotations of Java annotations. The content of this article and related articles are a series of articles. Friends in need can refer to the following

2. spring AOP extracts redis instance

##Introduction: 1. Definition annotation package com.efoxconn.ipebg.common.annotation; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.la ...

3. The immediate_sync attribute of transactional replication

Introduction: The immediate_sync attribute of transactional replication is turned off by default. This attribute It can be specified when creating a publication or modified after it is created. If immediate_sync is true, snapshot files and replicated transactions will be retained until data retention. Then

4. Oracle flashback table based on SCN number

Introduction: It is recommended to change the undo_retention parameter when installing oracle software. It is recommended to change the default value of 900 to 10800 seconds, which is 3 hours; alter system set undo_retention=1

##5.

Oracle backup retention policy (RETENTION POLICY)

Introduction: The backup manager RMAN provides the CONFIGURE RETENTION POLICY command to set the backup saving policy, that is, how long to keep the backup files. RMAN will backup files that have exceeded the time

6.

The difference between obsolete and expired in Rman backup

Introduction: obsolete: related to the retention policy. When a backup or copy is discarded according to the retention policy, it will be marked in this state. For example, if you set the recovery window to 7 days,

7.

Oracle read consistency study notes

Introduction: In order to avoid the error of ORA-1555 snapshot being too old, the undo_retention parameter appears, indicating that when a transaction is committed or rolled back, the data in the undo block used by the transaction needs to be How long to keep

8.

Oracle undo table space size estimation

Introduction: (UR) UNDO_RETENTION in seconds (UPS) Number of undo data blocks generated per second (DBS) Overhead varies based on exte

9.

How to estimate the size of UNDO tablespace required for Oracle database

Introduction: To determine the size of the UNDO tablespace required by Oracle, the following three pieces of information are required: UR UNDO_RETENTIONUPS in seconds Number of restore data blocks generated per second

10. Oracle UNDO table space daily maintenance and viewing operations

Introduction: undo table space Commonly used operations: (1) View the attributes of undo table space undotbs1: SQLgt; select b.tablespace_name,AUTOEXTENSIBLE,RETENTION f

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