【AWR】DBA_HIST檢視檢視儲存在AWR中的歷史資料

我們經常使用Oracle資料庫中的效能分析工具，awr，那麼如果我們需要檢查一些專項的東西，如何直接獲取相關資料呢？ 也就是說，那些awr的資料存放在哪裡，相關檢視有哪些？

注意在Oracle21c 之後 不再支援 NO-CDB模式了，所有部署均為CDB模式，需要pdb。

這些DBA_HIST檢視也可以分別與CDB級別和PDB級別的AWR_ROOT檢視和AWR_PDB檢視進行互換。例如，你可以使用AWR_PDB_ACTIVE_SESS_HISTORY檢視來檢索PDB級別上關於活動會話歷史的AWR資料，這相當於非多租戶環境下獨立資料庫中的DBA_HIST_ACTIVE_SESS_HISTORY檢視。如果沒有收集PDB級別的快照，AWR_PDB檢視將不會顯示任何AWR資料。

可以透過下面命令開啟pdb級別awr收集功能：參考命令

alter session set container=PDB1;
alter system set awr_pdb_autoflush_enabled=true;

DBA_HIST相關檢視參考如下：

DBA_HIST View	Description
DBA_HIST_ACTIVE_SESS_HISTORY	Displays the history of the contents of the in-memory active   session history for recent system activity.
DBA_HIST_BASELINE	Displays information about the baselines captured on the   system, such as the time range of each baseline and the baseline type.
DBA_HIST_BASELINE_DETAILS	Displays details about a specific baseline.
DBA_HIST_BASELINE_TEMPLATE	Displays information about the baseline templates used by the   system to generate baselines.
DBA_HIST_CON_SYS_TIME_MODEL	Displays historical system time model statistics, including   OLAP timed statistics.
DBA_HIST_CON_SYSMETRIC_HIST	Displays the historical information about the system metric   values.
DBA_HIST_CON_SYSMETRIC_SUMM	Displays history of the statistical summary of all the metric   values in the system metrics for the long duration (60 seconds) group.
DBA_HIST_CON_SYSSTAT	Displays historical system statistics, including OLAP kernel   statistics.
DBA_HIST_CON_SYSTEM_EVENT	Displays historical information about the total waits for an   event.
DBA_HIST_DATABASE_INSTANCE	Displays information about the database environment.
DBA_HIST_DB_CACHE_ADVICE	Displays historical predictions of the number of physical   reads for the cache size corresponding to each row.
DBA_HIST_DISPATCHER	Displays historical information for each dispatcher process at   the time of the snapshot.
DBA_HIST_DYN_REMASTER_STATS	Displays statistical information about the dynamic remastering   process.
DBA_HIST_IOSTAT_DETAIL	Displays historical I/O statistics aggregated by file type and   function.
DBA_HIST_RSRC_PDB_METRIC	Displays historical information about the Resource Manager   metrics for pluggable databases (PDBs) for the past one hour.
DBA_HIST_RSRC_METRIC	Displays historical information about the Resource Manager   metrics for consumer groups for the past one hour.
DBA_HIST_SHARED_SERVER_SUMMARY	Displays historical information for shared servers, such as   shared server activity, common queues and dispatcher queues.
DBA_HIST_SNAPSHOT	Displays information on snapshots in the system.
DBA_HIST_SQL_PLAN	Displays the SQL execution plans.
DBA_HIST_WR_CONTROL	Displays the settings for controlling AWR.
DBA_HIST_WR_SETTINGS	Displays the settings and metadata of the AWR.
DBA_HIST_PROCESS_WAITTIME	Displays CPU and wait time for a process type.

具體可參考官方文件，《Database Performance Tuning Guide》