Oracle教程 2023-02-24

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

本站中文解释

V$GG_APPLY_READER是Oracle的视图，它用于提供 GoldenGate 的变更数据应用的信息，查询V$GG_APPLY_READER可以查看各个变更数据应用操作的统计信息。

V$GG_APPLY_READER由下面几个列构成：

• APPLSID：变更数据应用的会话标识符；
• APPLNAME：变更数据应用器的名称；
• APPLIED_SEQNO：已应用的序列号；
• APPLIED_LAG：应用延迟；
• APPLIED_RATE：应用速度；
• APPLIED_BYTES：每秒已应用的字节；
• LAST_PURGE_NUM：最近清除的变更数；
• LAST_PURGE_TS：最近清除的时间戳；
• CHECKPOINT_NUM：检查点的变更数；
• CHECKPOINT_TS：检查点的时间戳；
• WALL_CLOCK_ELAPSED：真实时间消耗；
• CPU_ELAPSED：CPU时间消耗。

通过查询V$GG_APPLY_READER，可以查看各个变更数据应用操作的状态信息，以及应用速度、延迟情况。该视图可以用于分析应用延迟及其根源，优化配置调整，提高应用性能。

官方英文解释

V$GG_APPLY_READER displays information about each GoldenGate apply reader.

The apply reader is a process which reads (dequeues) messages from the queue, computes message dependencies, and builds transactions. It passes the transactions on to the coordinator in commit order for assignment to the apply servers. An apply reader is a subcomponent of an apply process used by Oracle GoldenGate Integrated Replicat.

Column	Datatype	Description
`SID`	`NUMBER`	Session ID of the reader’s session
`SERIAL#`	`NUMBER`	Serial number of the reader’s session
`APPLY#`	`NUMBER`	Apply process number. An apply process is an Oracle background process, prefixed by `ap`.
`APPLY_NAME`	`VARCHAR2(128)`	Name of the apply process
`STATE`	`VARCHAR2(36)`	Shows the state of the apply reader and the hash server. The possible values include: `INITIALIZING` – Starting up `IDLE` – Performing no work `DEQUEUE MESSAGES` – Dequeuing messages from the queue `SCHEDULE MESSAGES` – Computing dependencies between messages and assembling messages into transactions `SPILLING` – Spilling unapplied messages from memory to hard disk `PAUSED - WAITING FOR DDL TO COMPLETE` – Waiting for a data definition language (DDL) logical change record (LCR) to be applied The state of the apply reader is displayed first, followed by the state of the hash server. A semicolon separates the apply reader state from the hash server state.
`TOTAL_MESSAGES_DEQUEUED`	`NUMBER`	Total number of messages dequeued since the apply process was last started
`TOTAL_MESSAGES_SPILLED`	`NUMBER`	Number of messages spilled by the reader since the apply process was last started
`DEQUEUE_TIME`	`DATE`	Time when the last message was received
`DEQUEUED_MESSAGE_CREATE_TIME`	`DATE`	For captured messages, creation time at the source database of the last message received. For user-enqueued messages, time when the message was enqueued into the queue at the local database.
`SGA_USED`	`NUMBER`	Amount (in bytes) of SGA memory used by the apply process since it was last started
`ELAPSED_DEQUEUE_TIME`	`NUMBER`	Time elapsed (in hundredths of a second) dequeuing messages since the apply process was last started
`ELAPSED_SCHEDULE_TIME`	`NUMBER`	Time elapsed (in hundredths of a second) scheduling messages since the apply process was last started. Scheduling includes computing dependencies between messages and assembling messages into transactions.
`ELAPSED_SPILL_TIME`	`NUMBER`	Elapsed time (in hundredths of a second) spent spilling messages since the apply process was last started
`SPILL_LWM_SCN`	`NUMBER`	Spill low-watermark SCN
`PROXY_SID`	`NUMBER`	When the apply process uses combined capture and apply, the session ID of the propagation receiver that is responsible for direct communication between capture and apply. If the apply process does not use combined capture and apply, then this column is `0`.
`PROXY_SERIAL`	`NUMBER`	When the apply process uses combined capture and apply, the serial number of the propagation receiver that is responsible for direct communication between capture and apply. If the apply process does not use combined capture and apply, then this column is `0`.
`PROXY_SPID`	`VARCHAR2(12)`	When the apply process uses combined capture and apply, the process identification number of the propagation receiver that is responsible for direct communication between capture and apply. If the apply process does not use combined capture and apply, then this column is `0`.
`BYTES_RECEIVED`	`NUMBER`	When the apply process uses combined capture and apply, the number of bytes received by the apply process from the capture process since the apply process last started. If the apply process does not use combined capture and apply, then this column is not populated.
`DEQUEUED_POSITION`	`RAW(64)`	Dequeued position. This column is populated only for an apply process that is functioning as a GoldenGate inbound server.
`SPILL_LWM_POSITION`	`RAW(64)`	Spill low-watermark position. This column is populated only for an apply process that is functioning as a GoldenGate inbound server.
`OLDEST_TRANSACTION_ID`	`VARCHAR2(128)`	Oldest transaction ID
`TOTAL_LCRS_WITH_DEP`	`NUMBER`	Total number of LCRs with row-level dependencies since the apply process last started
`TOTAL_LCRS_WITH_WMDEP`	`NUMBER`	Total number of LCRs with watermark dependencies since the apply process last started. A watermark dependency occurs when an apply process must wait until the apply process’s low watermark reaches a particular threshold.
`TOTAL_IN_MEMORY_LCRS`	`NUMBER`	Total number of LCRs currently in memory
`SGA_ALLOCATED`	`NUMBER`	The total amount of shared memory (in bytes) allocated from the GoldenGate pool for the apply process since the apply process last started
`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

Note:

The ELAPSED_SCHEDULE_TIME column is only populated if the TIMED_STATISTICS initialization parameter is set to true, or if the STATISTICS_LEVEL initialization parameter is set to TYPICAL or ALL.

本站中文解释

官方英文解释

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