从Oracle10g开始引入了V$ACTIVE_SESSION_HISTORY视图,用于查询用户活动会话的历史信息,ASH组件 缺省每一秒收集一下活动会话的情况,间隔时间由_ash_sampling_interval 参数确 定.v$active_session_history包含了对于诊断故障非常有用的信息,这个视图也是生在ASH报表的来源.

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SQL> show parameter statistics;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
optimizer_use_pending_statistics boolean FALSE
statistics_level string TYPICAL
timed_os_statistics integer 0
timed_statistics boolean TRUE
SQL> desc v$active_session_history;
Name Null? Type
----------------------------------------- -------- ----------------------------
SAMPLE_ID NUMBER
SAMPLE_TIME TIMESTAMP(3)
SESSION_ID NUMBER
SESSION_SERIAL# NUMBER
SESSION_TYPE VARCHAR2(10)
FLAGS NUMBER
USER_ID NUMBER
SQL_ID VARCHAR2(13)
SQL_CHILD_NUMBER NUMBER
SQL_OPCODE NUMBER
FORCE_MATCHING_SIGNATURE NUMBER
TOP_LEVEL_SQL_ID VARCHAR2(13)
TOP_LEVEL_SQL_OPCODE NUMBER
SQL_PLAN_HASH_VALUE NUMBER
SQL_PLAN_LINE_ID NUMBER
SQL_PLAN_OPERATION VARCHAR2(30)
SQL_PLAN_OPTIONS VARCHAR2(30)
SQL_EXEC_ID NUMBER
SQL_EXEC_START DATE
PLSQL_ENTRY_OBJECT_ID NUMBER
PLSQL_ENTRY_SUBPROGRAM_ID NUMBER
PLSQL_OBJECT_ID NUMBER
PLSQL_SUBPROGRAM_ID NUMBER
QC_INSTANCE_ID NUMBER
QC_SESSION_ID NUMBER
QC_SESSION_SERIAL# NUMBER
EVENT VARCHAR2(64)
EVENT_ID NUMBER
EVENT# NUMBER
SEQ# NUMBER
P1TEXT VARCHAR2(64)
P1 NUMBER
P2TEXT VARCHAR2(64)
P2 NUMBER
P3TEXT VARCHAR2(64)
P3 NUMBER
WAIT_CLASS VARCHAR2(64)
WAIT_CLASS_ID NUMBER
WAIT_TIME NUMBER
SESSION_STATE VARCHAR2(7)
TIME_WAITED NUMBER
BLOCKING_SESSION_STATUS VARCHAR2(11)
BLOCKING_SESSION NUMBER
BLOCKING_SESSION_SERIAL# NUMBER
CURRENT_OBJ# NUMBER
CURRENT_FILE# NUMBER
CURRENT_BLOCK# NUMBER
CURRENT_ROW# NUMBER
CONSUMER_GROUP_ID NUMBER
XID RAW(8)
REMOTE_INSTANCE# NUMBER
IN_CONNECTION_MGMT VARCHAR2(1)
IN_PARSE VARCHAR2(1)
IN_HARD_PARSE VARCHAR2(1)
IN_SQL_EXECUTION VARCHAR2(1)
IN_PLSQL_EXECUTION VARCHAR2(1)
IN_PLSQL_RPC VARCHAR2(1)
IN_PLSQL_COMPILATION VARCHAR2(1)
IN_JAVA_EXECUTION VARCHAR2(1)
IN_BIND VARCHAR2(1)
IN_CURSOR_CLOSE VARCHAR2(1)
SERVICE_HASH NUMBER
PROGRAM VARCHAR2(48)
MODULE VARCHAR2(48)
ACTION VARCHAR2(32)
CLIENT_ID VARCHAR2(64)