DBA_HIST_ACTIVE_SESS_HISTORY

DBA_HIST_ACTIVE_SESS_HISTORY displays the history of the contents of the in-memory active session history of recent system activity. This view contains snapshots of V$ACTIVE_SESSION_HISTORY. See "V$ACTIVE_SESSION_HISTORY" for further interpretation details for many of these columns (except SNAP_ID, DBID, and INSTANCE_NUMBER).

Column	Datatype	Description
`SNAP_ID`	`NUMBER`	Unique snapshot ID
`DBID`	`NUMBER`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	Instance number for the snapshot
`SAMPLE_ID`	`NUMBER`	ID of the sample
`SAMPLE_TIME`	`TIMESTAMP(3)`	Time of the sample
`SESSION_ID`	`NUMBER`	Session identifier
`SESSION_SERIAL#`	`NUMBER`	Session serial number (used to uniquely identify a session's objects)
`USER_ID`	`NUMBER`	Oracle user identifier
`SQL_ID`	`VARCHAR2(13)`	SQL identifier of the SQL statement that is currently being executed
`SQL_CHILD_NUMBER`	`NUMBER`	Child number of the SQL statement that is currently being executed
`SQL_PLAN_HASH_VALUE`	`NUMBER`	Numerical representation of the SQL plan for the cursor
`FORCE_MATCHING_SIGNATURE`	`NUMBER`	The signature used when the `CURSOR_SHARING` parameter is set to `FORCE`
`SQL_OPCODE`	`NUMBER`	Indicates what phase of operation the SQL statement is in
`SERVICE_HASH`	`NUMBER`	Hash that identifies the Service
`SESSION_TYPE`	`VARCHAR2(10)`	Session type: `FOREGROUND` `BACKGROUND`
`SESSION_STATE`	`VARCHAR2(7)`	Session state: `WAITING` `ON` `CPU`
`QC_SESSION_ID`	`NUMBER`	Query coordinator session ID
`QC_INSTANCE_ID`	`NUMBER`	Query coordinator instance ID
`BLOCKING_SESSION`	`NUMBER`	Session identifier of the blocking session. Populated only when the session was waiting for enqueues or a "buffer busy" wait. Maps to `V$SESSION.BLOCKING_SESSION`.
`BLOCKING_SESSION_STATUS`	`VARCHAR2(11)`	Status of the blocking session: `VALID` `NO HOLDER` `GLOBAL` `NOT IN WAIT` `UNKNOWN`
`BLOCKING_SESSION_SERIAL#`	`NUMBER`	Serial number of the blocking session
`EVENT`	`VARCHAR2(64)`	If `SESSION_STATE = WAITING`, then the event for which the session was waiting at the time of sampling. If `SESSION_STATE = ON CPU`, then this column will be NULL.
`EVENT_ID`	`NUMBER`	Identifier of the resource or event for which the session is waiting or for which the session last waited
`SEQ#`	`NUMBER`	Sequence number that uniquely identifies the wait (incremented for each wait)
`P1TEXT`	`VARCHAR2(64)`	Text of first additional parameter
`P1`	`NUMBER`	First additional parameter
`P2TEXT`	`VARCHAR2(64)`	Text of second additional parameter
`P2`	`NUMBER`	Second additional parameter
`P3TEXT`	`VARCHAR2(64)`	Text of third additional parameter
`P3`	`NUMBER`	Third additional parameter
`WAIT_CLASS`	`VARCHAR2(64)`	Wait class name of the event for which the session was waiting at the time of sampling. Interpretation is similar to that of the `EVENT` column. Maps to `V$SESSION.WAIT_CLASS`.
`WAIT_CLASS_ID`	`NUMBER`	Wait class identifier of the event for which the session was waiting at the time of sampling. Interpretation is similar to that of the `EVENT` column. Maps to `V$SESSION.WAIT_CLASS_ID`.
`WAIT_TIME`	`NUMBER`	Total wait time for the event for which the session last waited (`0` if currently waiting)
`TIME_WAITED`	`NUMBER`	Time that the current session actually spent waiting for the event. This column is set for waits that were in progress at the time the sample was taken.
`XID`	`RAW(8)`	Transaction ID that the session was working on at the time of sampling. `V$SESSION` does not contain this information.
`CURRENT_OBJ#`	`NUMBER`	Object ID of the object that the session is currently referencing. This information is only available if the session was waiting for Application, Cluster, Concurrency, and User I/O wait events. Maps to `V$SESSION.ROW_WAIT_OBJ#`.
`CURRENT_FILE#`	`NUMBER`	File number of the file containing the block that the session is currently referencing. This information is only available if the session was waiting for Cluster, Concurrency, and User I/O wait events. Maps to `V$SESSION.ROW_WAIT_FILE#`.
`CURRENT_BLOCK#`	`NUMBER`	ID of the block that the session is currently referencing
`PROGRAM`	`VARCHAR2(48)`	Name of the operating system program
`MODULE`	`VARCHAR2(48)`	Name of the currently executing module as set by the `DBMS_APPLICATION_INFO.SET_MODULE` procedure
`ACTION`	`VARCHAR2(32)`	Name of the currently executing action as set by the `DBMS_APPLICATION_INFO.SET_ACTION` procedure
`CLIENT_ID`	`VARCHAR2(64)`	Client identifier of the session