<div style="font-family:微軟雅黑;font-size:14px;line-height:21px;white-space:normal;widows:auto;background-color:#FFFFFF;"> The types of standby databases are as follows: </div> <div style="font-family:微軟雅黑;font-size:14px;line-height:21px;white-space:normal;widows:auto;background-color:#FFFFFF;"> <ul style="margin-top:0px;margin-bottom:0px;background-color:inherit;"> <li style="font-size:small;font-family:Tahoma, sans-serif;color:#222222;"> hysical standby database //物理備庫 ----只讀 Provides a physically identical copy of the primary database, with on disk database structures that are identical to the primary database on a block-for-block basis. The database schema, including indexes, are the same. A physical standby database is kept synchronized with the primary database, through Redo Apply, which recovers the redo data received from the primary database and applies the redo to the physical standby database. As of Oracle Database 11g release 1 (11.1), a physical standby database can receive and apply redo while it is open for read-only access. A physical standby database can therefore be used concurrently for data protection and reporting. 提供了一個物理上相同的主資料庫的副本,與磁碟上資料庫結構與主資料庫block-for-block基礎上。資料庫模式,包括索引,是相同的。物理備用資料庫與主資料庫保持同步,透過重做,重做資料恢復了從主資料庫和應用物理備用資料庫的重做。 Oracle資料庫11g的版本1(11.1),物理備用資料庫可以接收和重做時它是開放申請只讀訪問。物理備用資料庫因此可以同時用於資料保護和報告。 </li> <li style="font-size:small;font-family:Tahoma, sans-serif;color:#222222;"> Logical standby database //邏輯備庫------可sql查詢和檢視統計報告、升級資料庫和補丁集 Contains the same logical information as the production database, although the physical organization and structure of the data can be different. The logical standby database is kept synchronized with the primary database through SQL Apply, which transforms the data in the redo received from the primary database into SQL statements and then executes the SQL statements on the standby database. A logical standby database can be used for other business purposes in addition to disaster recovery requirements. This allows users to access a logical standby database for queries and reporting purposes at any time. Also, using a logical standby database, you can upgrade Oracle Database software and patch sets with almost no downtime. Thus, a logical standby database can be used concurrently for data protection, reporting, and database upgrades. 包含相同的邏輯資訊生產資料庫,儘管資料的物理組織和結構可以是不同的。邏輯備用資料庫與主資料庫透過SQL應用保持同步,從而使資料重做了從主資料庫為SQL語句然後在備用資料庫上執行SQL語句。 一個邏輯備用資料庫可用於其他商業用途除了災難恢復需求。這允許使用者訪問一個邏輯備用資料庫來進行查詢和報告。此外,使用一個邏輯備用資料庫,您可以升級Oracle資料庫軟體和補丁集幾乎沒有停機時間。因此,可以使用一個邏輯備用資料庫併發資料保護,報告和資料庫升級。 </li> <li style="font-size:small;font-family:Tahoma, sans-serif;color:#222222;"> Snapshot Standby Database //快照備庫----read write完全可更新備用資料庫 </li> </ul> </div> <div style="font-family:微軟雅黑;font-size:14px;line-height:21px;white-space:normal;widows:auto;background-color:#FFFFFF;"> <ul style="margin-top:0px;margin-bottom:0px;color:#222222;font-family:Tahoma, sans-serif;font-size:small;"> <li style="background-color:inherit;"> A snapshot standby database is a fully updatable standby database. Like a physical or logical standby database, a snapshot standby database receives and archives redo data from a primary database. Unlike a physical or logical standby database, a snapshot standby database does not apply the redo data that it receives. The redo data received by a snapshot standby database is not applied until the snapshot standby is converted back into a physical standby database, after first discarding any local updates made to the snapshot standby database. A snapshot standby database is best used in scenarios that require a temporary, updatable snapshot of a physical standby database. Note that because redo data received by a snapshot standby database is not applied until it is converted back into a physical standby, the time needed to recover from a primary database failure is directly proportional to the amount of redo data that needs to be applied. 備用資料庫快照是一個完全可更新備用資料庫。 就像一個物理或邏輯備用資料庫,備用資料庫快照從主資料庫和檔案接收重做資料。不像物理或邏輯備用資料庫,備用資料庫快照不適用它收到的重做資料。不想對快照備份資料庫進行本地更新（指dml）後，直到重做資料接收到一個備用資料庫快照被應用後，快照備庫才轉換為物理備用資料庫, 備用資料庫快照最好需要一個臨時的場景中使用,可更新快照的一個物理備用資料庫。注意,因為重做資料接收到一個備用資料庫快照不是應用,直到它被轉換回一個物理備用,從主資料庫故障恢復所需的時間成正比的重做資料量,需要應用。 </li> </ul> </div>

ORACLE DG之備庫角色

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