Oracle教程 2023-02-26

Oracle 视图 V$FLASHBACK_TXN_MODS 官方解释，作用，如何使用详细说明

本站中文解释

V$FLASHBACK_TXN_MODS视图用于查看当前实例下正在进行flashback事务（Flashback Transaction）的更改，该视图内包含所有正在进行flashback修改的事务和表。用户可通过它获取事务提交前和提交后的更新行，也可以查看事务是否已经提交，以及它包含哪些更改。

V$FLASHBACK_TXN_MODS视图只在使用Flashback Transaction时可用，而且只能由用户查看，不能修改或删除表中的数据。其中字段FTXID用于标记被修改的行，精确记录了被修改的表的名字、修改的列的名字和修改的内容。

使用V$FLASHBACK_TXN_MODS视图的方法如下：

1.确定正在进行Flashback Transaction的表/库
使用SQL脚本：
SELECT * from V$FLASHBACK_TXN_MODS;

2.检查存储在此表/库中的更改
使用SQL脚本：
SELECT FTXID, FTX_OPTY, TABLE_NAME, COLUMN_NAME, OLD_VALUE, NEW_VALUE
FROM V$FLASHBACK_TXN_MODS WHERE FTXID = ;

其中 txidNumber 所指定的值在第一步上语句中可以获得。

3.恢复数据
使用SQL脚本：
EXECUTE FLASHBACK_TRANSACTION(txidNumber);

其中 txidNumber 所指定的值在第一步上语句中可以获得。

官方英文解释

V$FLASHBACK_TXN_MODS displays the individual modifications of all the transactions in memory.

This view is relevant AFTER a compensating transaction has been started through the DBMS_FLASHBACK.TRANSACTION_BACKOUT() set of functions, and is no longer relevant once the compensating transaction is either committed or rolled back. It also provides a tabular representation of the undo SQL that is not available through the CLOB XML construct in the DBA_FLASHBACK_TXN_REPORT view.

Column	Datatype	Description
`COMPENSATING_XID`	`RAW(8)`	Transaction ID of the compensating transaction
`COMPENSATING_TXN_NAME`	`VARCHAR2(255)`	Name of the compensating transaction
`XID`	`RAW(8)`	Transaction ID of a relevant transaction found in memory
`TXN_NAME`	`VARCHAR2(255)`	Name of the transaction with `XID` as the transaction ID; NULL if none
`PARENT_XID`	`RAW(8)`	Parent transaction ID (for a PDML transaction)
`INTERESTING`	`NUMBER`	If the transaction is in the transaction dependency graph
`ORIGINAL`	`NUMBER`	If the transaction is part of the input set provided
`BACKOUT_SEQ`	`NUMBER`	Order in which the transaction has been backed out
`UNDO_SQL`	`VARCHAR2(4000)`	Undo SQL for the modification
`UNDO_SQL_SQN`	`NUMBER`	Order in which the given SQL has been executed to back out this transaction
`UNDO_SQL_SUB_SQN`	`NUMBER`	If the undo SQL is greater than 4000 bytes, then a sequence number, starting from `1`, of a 4000-byte division of the undo SQL
`BACKOUT_SQL_ID`	`NUMBER`	SQL ID of the undo SQL (used only for this compensating transaction)
`OPERATION`	`VARCHAR2(128)`	Operation (such as insert/update/delete) performed by the forward-going operation
`BACKEDOUT`	`NUMBER`	Indicates whether the transaction has been backed out as of now
`CONFLICT_MOD`	`NUMBER`	If the concerned modification is causing a conflict
`MODS_PER_LCR`	`NUMBER`	Sometimes an LCR could cause multiple modifications (for example, an update of an IOT could actually be a delete followed by an insert)
`CON_ID`	`NUMBER`	The ID of the container to which the data pertains. Possible values include: `0`: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. `1`: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data

本站中文解释

官方英文解释

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