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Oracle 视图 DBA_HIST_SNAPSHOT 官方解释，作用，如何使用详细说明

本站中文解释

Oracle视图DBA_HIST_SNAPSHOT是一个系统建模视图，存储了在周期性数据库快照中所收集的概要信息以及执行任务的详细信息。该视图用于捕获、汇总和跟踪时间段内数据库活动的历史信息，主要用于性能分析和故障排除。DBA_HIST_SNAPSHOT中维护了概要信息：俯视图会记录所有与排它状态 (exclusive mode) 不相关的事务。 使用DBA_HIST_SNAPSHOT视图可以：
1、确定数据库运行时发生的事件；
2、查看数据库快照信息，包括等待事件，活动会话，SQL语句等；
3、监控系统活动，以查看特定的SQL语句的性能，以及CPU和等待时间；
4、为性能调优和故障排除提供资料，提供数据库发展趋势的分析。

官方英文解释

DBA_HIST_SNAPSHOT displays information about the snapshots in the Workload Repository.

Column Datatype NULL Description

SNAP_ID

NUMBER

NOT NULL

Unique snapshot ID

DBID

NUMBER

NOT NULL

Database ID for the snapshot

INSTANCE_NUMBER

NUMBER

NOT NULL

Instance number for the snapshot

STARTUP_TIME

TIMESTAMP(3)

NOT NULL

Startup time of the instance

BEGIN_INTERVAL_TIME

TIMESTAMP(3)

NOT NULL

Time at the beginning of the snapshot interval

END_INTERVAL_TIME

TIMESTAMP(3)

NOT NULL

Time at the end of the snapshot interval; the actual time the snapshot was taken

FLUSH_ELAPSED

INTERVAL DAY(5) TO SECOND(1)

Amount of time to perform the snapshot

SNAP_LEVEL

NUMBER

Snapshot level

ERROR_COUNT

NUMBER

Number of errors occurring in the tables for the particular snapshot

SNAP_FLAG

NUMBER

Condition under which the snapshot was inserted. Possible values are:

0 – Snapshot was taken automatically by the Manageability Monitor Process (MMON process)

1 – Manual snapshot created using a PL/SQL package

2 – Imported snapshot

4 – Snapshot taken while Diagnostic Pack or Tuning Pack was not enabled

SNAP_TIMEZONE

INTERVAL DAY(0) TO SECOND(0)

Snapshot time zone expressed as offset from UTC (Coordinated Universal Time) time zone

BEGIN_INTERVAL_TIME_TZ

TIMESTAMP(3) WITH TIME ZONE

Time at the beginning of the snapshot interval, with timezone

END_INTERVAL_TIME_TZ

TIMESTAMP(3) WITH TIME ZONE

Time at the end of the snapshot interval; the actual time the snapshot was taken, with timezone

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

See Also:

Table F-1 for more information about the MMON process


数据运维技术 » Oracle 视图 DBA_HIST_SNAPSHOT 官方解释，作用，如何使用详细说明
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