V$SESSION
This view lists session information for each current session.
| Column | Datatype | Description |
|---|---|---|
SADDR |
RAW(4 | 8) |
Session address |
SID |
NUMBER |
Session identifier |
SERIAL# |
NUMBER |
Session serial number. Used to uniquely identify a session's objects. Guarantees that session-level commands are applied to the correct session objects if the session ends and another session begins with the same session ID. |
AUDSID |
NUMBER |
Auditing session ID |
PADDR |
RAW(4 | 8) |
Address of the process that owns the session |
USER# |
NUMBER |
Oracle user identifier |
USERNAME |
VARCHAR2(30) |
Oracle username |
COMMAND |
NUMBER |
Command in progress (last statement parsed); for a list of values, see Table 7-5. These values also appear in the AUDIT_ACTIONS table. |
OWNERID |
NUMBER |
The column contents are invalid if the value is 2147483644. Otherwise, this column contains the identifier of the user who owns the migratable session. For operations using Parallel Slaves, interpret this value as a 4-byte value. The low-order 2 bytes of which represent the session number, and the high-order bytes the instance ID of the query coordinator. |
TADDR |
VARCHAR2(8) |
Address of transaction state object |
LOCKWAIT |
VARCHAR2(8) |
Address of lock waiting for; null if none |
STATUS |
VARCHAR2(8) |
Status of the session:
|
SERVER |
VARCHAR2(9) |
Server type (DEDICATED| SHARED| PSEUDO| NONE) |
SCHEMA# |
NUMBER |
Schema user identifier |
SCHEMANAME |
VARCHAR2(30) |
Schema user name |
OSUSER |
VARCHAR2(30) |
Operating system client user name |
PROCESS |
VARCHAR2(12) |
Operating system client process ID |
MACHINE |
VARCHAR2(64) |
Operating system machine name |
TERMINAL |
VARCHAR2(30) |
Operating system terminal name |
PROGRAM |
VARCHAR2(48) |
Operating system program name |
TYPE |
VARCHAR2(10) |
Session type |
SQL_ADDRESS |
RAW(4 | 8) |
Used with SQL_HASH_VALUE to identify the SQL statement that is currently being executed |
SQL_HASH_VALUE |
NUMBER |
Used with SQL_ADDRESS to identify the SQL statement that is currently being executed |
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 |
PREV_SQL_ADDR |
RAW(4 | 8) |
Used with PREV_HASH_VALUE to identify the last SQL statement executed |
PREV_HASH_VALUE |
NUMBER |
Used with SQL_HASH_VALUE to identify the last SQL statement executed |
PREV_SQL_ID |
VARCHAR2(13) |
SQL identifier of the last SQL statement executed |
PREV_CHILD_NUMBER |
NUMBER |
Child number of the last SQL statement executed |
MODULE |
VARCHAR2(48) |
Name of the currently executing module as set by calling theDBMS_APPLICATION_INFO.SET_MODULE procedure |
MODULE_HASH |
NUMBER |
Hash value of the above MODULE |
ACTION |
VARCHAR2(32) |
Name of the currently executing action as set by calling theDBMS_APPLICATION_INFO.SET_ACTION procedure |
ACTION_HASH |
NUMBER |
Hash value of the above action name |
CLIENT_INFO |
VARCHAR2(64) |
Information set by the DBMS_APPLICATION_INFO.SET_CLIENT_INFO procedure |
FIXED_TABLE_SEQUENCE |
NUMBER |
This contains a number that increases every time the session completes a call to the database and there has been an intervening select from a dynamic performance table. This column can be used by performance monitors to monitor statistics in the database. Each time the performance monitor looks at the database, it only needs to look at sessions that are currently active or have a higher value in this column than the highest value that the performance monitor saw the last time. All the other sessions have been idle since the last time the performance monitor looked at the database. |
ROW_WAIT_OBJ# |
NUMBER |
Object ID for the table containing the row specified in ROW_WAIT_ROW# |
ROW_WAIT_FILE# |
NUMBER |
Identifier for the datafile containing the row specified in ROW_WAIT_ROW#. This column is valid only if the session is currently waiting for another transaction to commit and the value ofROW_WAIT_OBJ# is not -1. |
ROW_WAIT_BLOCK# |
NUMBER |
Identifier for the block containing the row specified in ROW_WAIT_ROW#. This column is valid only if the session is currently waiting for another transaction to commit and the value ofROW_WAIT_OBJ# is not -1. |
ROW_WAIT_ROW# |
NUMBER |
Current row being locked. This column is valid only if the session is currently waiting for another transaction to commit and the value of ROW_WAIT_OBJ# is not -1. |
LOGON_TIME |
DATE |
Time of logon |
LAST_CALL_ET |
NUMBER |
If the session STATUS is currently ACTIVE, then the value represents the elapsed time in seconds since the session has become active. If the session |
PDML_ENABLED |
VARCHAR2(3) |
This column has been replaced by column PDML_STATUS |
FAILOVER_TYPE |
VARCHAR2(13) |
Indicates whether and to what extent transparent application failover (TAF) is enabled for the session:
See Also:
|
FAILOVER_METHOD |
VARCHAR2(10) |
Indicates the transparent application failover method for the session:
|
FAILED_OVER |
VARCHAR2(3) |
Indicates whether the session is running in failover mode and failover has occurred (YES) or not (NO) |
RESOURCE_CONSUMER_GROUP |
VARCHAR2(32) |
Name of the session's current resource consumer group |
PDML_STATUS |
VARCHAR2(8) |
If ENABLED, the session is in a PARALLEL DML enabled mode. If DISABLED, PARALLEL DML enabled mode is not supported for the session. If FORCED, the session has been altered to force PARALLEL DML. |
PDDL_STATUS |
VARCHAR2(8) |
If ENABLED, the session is in a PARALLEL DDL enabled mode. If DISABLED, PARALLEL DDL enabled mode is not supported for the session. If FORCED, the session has been altered to force PARALLEL DDL. |
PQ_STATUS |
VARCHAR2(8) |
If ENABLED, the session is in a PARALLEL QUERY enabled mode. If DISABLED, PARALLEL QUERY enabled mode is not supported for the session. If FORCED, the session has been altered to force PARALLEL QUERY. |
CURRENT_QUEUE_DURATION |
NUMBER |
If queued (1), the current amount of time the session has been queued. If not currently queued, the value is 0. |
CLIENT_IDENTIFIER |
VARCHAR2(64) |
Client identifier of the session |
BLOCKING_SESSION_STATUS |
VARCHAR2(11) |
Blocking session status:
|
BLOCKING_INSTANCE |
NUMBER |
Instance identifier of blocking session |
BLOCKING_SESSION |
NUMBER |
Session identifier of blocking session |
SEQ# |
NUMBER |
Sequence number that uniquely identifies the wait. Incremented for each wait. |
EVENT# |
NUMBER |
Event number |
EVENT |
VARCHAR2(64) |
Resource or event for which the session is waiting See Also: Appendix C, "Oracle Wait Events" |
P1TEXT |
VARCHAR2(64) |
Description of the first additional parameter |
P1 |
NUMBER |
First additional parameter |
P1RAW |
RAW(4) |
First additional parameter |
P2TEXT |
VARCHAR2(64) |
Description of the second additional parameter |
P2 |
NUMBER |
Second additional parameter |
P2RAW |
RAW(4) |
Second additional parameter |
P3TEXT |
VARCHAR2(64) |
Description of the third additional parameter |
P3 |
NUMBER |
Third additional parameter |
P3RAW |
RAW(4) |
Third additional parameter |
WAIT_CLASS_ID |
NUMBER |
Identifier of the wait class |
WAIT_CLASS# |
NUMBER |
Number of the wait class |
WAIT_CLASS |
VARCHAR2(64) |
Name of the wait class |
WAIT_TIME |
NUMBER |
A nonzero value is the session's last wait time. A zero value means the session is currently waiting. |
SECONDS_IN_WAIT |
NUMBER |
If WAIT_TIME = 0, then SECONDS_IN_WAIT is the seconds spent in the current wait condition. IfWAIT_TIME > 0, then SECONDS_IN_WAIT is the seconds since the start of the last wait, andSECONDS_IN_WAIT - WAIT_TIME / 100 is the active seconds since the last wait ended. |
STATE |
VARCHAR2(19) |
Wait state:
|
SERVICE_NAME |
VARCHAR2(64) |
Service name of the session |
SQL_TRACE |
VARCHAR2(8) |
Indicates whether SQL tracing is enabled (ENABLED) or disabled (DISABLED) |
SQL_TRACE_WAITS |
VARCHAR2(5) |
Indicates whether wait tracing is enabled (TRUE) or not (FALSE) |
SQL_TRACE_BINDS |
VARCHAR2(5) |
Indicates whether bind tracing is enabled (
|
V$PROCESS
This view contains information about the currently active processes. While the LATCHWAIT column indicates what latch a process is waiting for, the LATCHSPINcolumn indicates what latch a process is spinning on. On multi-processor machines, Oracle processes will spin on a latch before waiting on it.
| Column | Datatype | Description |
|---|---|---|
ADDR |
RAW(4 | 8) |
Address of process state object |
PID |
NUMBER |
Oracle process identifier |
SPID |
VARCHAR2(12) |
Operating system process identifier |
USERNAME |
VARCHAR2(15) |
Operating system process username. Any two-task user coming across the network has "-T" appended to the username. |
SERIAL# |
NUMBER |
Process serial number |
TERMINAL |
VARCHAR2(30) |
Operating system terminal identifier |
PROGRAM |
VARCHAR2(48) |
Program in progress |
TRACEID |
VARCHAR2(255) |
Trace file identifier |
BACKGROUND |
VARCHAR2(1) |
1 for a background process; NULL for a normal process |
LATCHWAIT |
VARCHAR2(8) |
Address of latch the process is waiting for; NULL if none |
LATCHSPIN |
VARCHAR2(8) |
Address of the latch the process is spinning on; NULL if none |
PGA_USED_MEM |
NUMBER |
PGA memory currently used by the process |
PGA_ALLOC_MEM |
NUMBER |
PGA memory currently allocated by the process (including free PGA memory not yet released to the operating system by the server process) |
PGA_FREEABLE_MEM |
NUMBER |
Allocated PGA memory which can be freed |
PGA_MAX_MEM |
NUMBER |
Maximum PGA memory ever allocated by the process |
V$SESSION中的常用列
V$SESSION是基礎信息視圖，用於找尋用戶SID或SADDR。不過，它也有一些列會動態的變化，可用於檢查用戶。如例：
SQL_HASH_VALUE，SQL_ADDRESS：這兩列用於鑒別默認被session執行的SQL語句。如果為null或0，那就說明這個session沒有執行任何SQL語句。PREV_HASH_VALUE和PREV_ADDRESS兩列用來鑒別被session執行的上一條語句。
注意：當使用SQL*Plus進行選擇時，確認你重定義的列寬不小於11以便看到完整的數值。
STATUS：這列用來判斷session狀態是：
Achtive：正執行SQL語句(waiting for/using a resource)
Inactive：等待操作(即等待需要執行的SQL語句)
Killed：被標注為刪除
下列各列提供session的信息，可被用於當一個或多個combination未知時找到session。
Session信息
SID：SESSION標識，常用於連接其它列
SERIAL#：如果某個SID又被其它的session使用的話則此數值自增加(當一個 SESSION結束，另一個SESSION開始並使用了同一個SID)。
AUDSID：審查session ID唯一性，確認它通常也用於當尋找並行查詢模式
USERNAME：當前session在oracle中的用戶名。
Client信息
數據庫session被一個運行在數據庫服務器上或從中間服務器甚至桌面通過SQL*Net連接到數據庫的客戶端進程啟動，下列各列提供這個客戶端的信息
OSUSER：客戶端操作系統用戶名
MACHINE：客戶端執行的機器
TERMINAL：客戶端運行的終端
PROCESS：客戶端進程的ID
PROGRAM：客戶端執行的客戶端程序
要顯示用戶所連接PC的 TERMINAL、OSUSER，需在該PC的ORACLE.INI或Windows中設置關鍵字TERMINAL，USERNAME。
Application信息
調用DBMS_APPLICATION_INFO包以設置一些信息區分用戶。這將顯示下列各列。
CLIENT_INFO：DBMS_APPLICATION_INFO中設置
ACTION：DBMS_APPLICATION_INFO中設置
MODULE：DBMS_APPLICATION_INFO中設置
下列V$SESSION列同樣可能會被用到：
ROW_WAIT_OBJ#
ROW_WAIT_FILE#
ROW_WAIT_BLOCK#
ROW_WAIT_ROW#
V$SESSION中的連接列
Column View Joined Column(s)
SID V$SESSION_WAIT,,V$SESSTAT,,V$LOCK,V$SESSION_EVENT,V$OPEN_CURSOR SID
(SQL_HASH_VALUE, SQL_ADDRESS) V$SQLTEXT, V$SQLAREA, V$SQL (HASH_VALUE, ADDRESS)
(PREV_HASH_VALUE, PREV_SQL_ADDRESS) V$SQLTEXT, V$SQLAREA, V$SQL (HASH_VALUE, ADDRESS)
TADDR V$TRANSACTION ADDR
PADDR V$PROCESS ADDR
示例：
1.查找你的session信息
SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS
FROM V$SESSION WHERE audsid = userenv('SESSIONID');
2.當machine已知的情況下查找session
SELECT SID, OSUSER, USERNAME, MACHINE, TERMINAL
FROM V$SESSION
WHERE terminal = 'pts/tl' AND machine = 'rgmdbs1';
查找當前被某個指定session正在運行的sql語句。假設sessionID為100
select b.sql_text
from v$session a,v$sqlarea b
where a.sql_hash_value=b.hash_value and a.sid=100
尋找被指定session執行的SQL語句是一個公共需求，如果session是瓶頸的主要原因，那根據其當前在執行的語句可以查看session在做些什么。
.如果數據庫瓶頸是系統資源(如：cpu,內存)，並且占用資源最多的用戶總是停留在某幾個服務進程，那么進行如下諸項：
1>.找出資源進程
2>.找出它們的session,你必須將進程與會話聯系起來。
3>.找出為什么session占用了如此多的資源
2.SQL跟蹤文件名是基於服務進程的操作系統進程ID。要找出session的跟蹤文件，你必須將session與服務進程聯系起來。
3.某些事件，如rdbms ipc reply，鑒別session進程的Oracle進程ID在等什么。要發現這些進程在做什么，你必須找出它們的session。
4.你所看到的服務器上的后台進程(DBWR,LGWR,PMON等)都是服務進程。要想知道他們在做什么，你必須找到他們的session。
V$PROCESS中的常用列
ADDR：進程對象地址
PID：oracle進程ID
SPID：操作系統進程ID
V$PROCESS中的連接列
Column View Joined Column(s)
ADDR V$SESSION PADDR
示例：
1.查找指定系統用戶在oracle中的session信息及進程id，假設操作系統用戶為：junsansi
select s.sid,s.SERIAL#, s.username,p.spid
from v$session s, v$process p
where s.osuser = 'junsansi'
and s.PADDR = p.ADDR
2.查看鎖和等待
SELECT /*+ rule */
lpad(' ', decode(l.xidusn, 0, 3, 0)) || l.oracle_username User_name,
o.owner,o.object_name,o.object_type,s.sid,s.serial#,p.spid
FROM v$locked_object l, dba_objects o, v$session s, v$process p
WHERE l.object_id = o.object_id
AND l.session_id = s.sid and s.paddr = p.addr
ORDER BY o.object_id, xidusn DESC
附注：
在linux環境可以通過ps查看進程信息包括pid,windows中任務管理器的PID與v$process中pid不能一一對應，這塊在oracleDocument中也沒有找到介紹，后來google了一下，有資料介紹說是由於windows是多線程服務器,每個進程包含一系列線程。這點於unix等不同，Unix每個Oralce進程獨立存在，在Nt上所有線程由Oralce進程衍生。
要在windows中顯示oracle相關進程pid，我們可以通過一個簡單的sql語句來實現。
SELECT s.SID, p.pid, p.spid signaled, s.osuser, s.program
FROM v$process p, v$session s
WHERE p.addr = s.paddr;
SID PID SIGNALED OSUSER PROGRAM
1 2 2452 SYSTEM ORACLE.EXE
2 3 2460 SYSTEM ORACLE.EXE
3 4 2472 SYSTEM ORACLE.EXE
4 5 2492 SYSTEM ORACLE.EXE
5 6 2496 SYSTEM ORACLE.EXE
6 7 2508 SYSTEM ORACLE.EXE
7 8 2520 SYSTEM ORACLE.EXE
8 9 2524 SYSTEM ORACLE.EXE
10 12 1316 JSSjunsansi PlSqlDev.exe
9 13 3420 JSSjunsansi PlSqlDev.exe
13 14 660 JSSjunsansi PlSqlDev.exe
還可以通過和 v$bgprocess 連接查詢到后台進程的名字：
SELECT s.SID SID, p.spid threadid, p.program processname, bg.NAME NAME
FROM v$process p, v$session s, v$bgprocess bg
WHERE p.addr = s.paddr
AND p.addr = bg.paddr
AND bg.paddr <> '00';
SID THREADID PROCESSNAME NAME
1 2452 ORACLE.EXE PMON
2 2460 ORACLE.EXE DBW0
3 2472 ORACLE.EXE LGWR
4 2492 ORACLE.EXE CKPT
5 2496 ORACLE.EXE SMON
6 2508 ORACLE.EXE RECO
7 2520 ORACLE.EXE CJQ0
8 2524 ORACLE.EXE QMN0
Eygle大師寫了一段sql腳本getsql.sql，用來獲取指定pid正在執行的sql語句，在此也附注上來。
REM getsql.sql
REM author eygle
REM 在windows上,已知進程ID,得到當前正在執行的語句
REM 在windows上,進程ID為16進制,需要轉換,在UNIX直接為10進制
SELECT /*+ ORDERED */
sql_text
FROM v$sqltext a
WHERE (a.hash_value, a.address) IN (
SELECT DECODE (sql_hash_value,
0, prev_hash_value,
sql_hash_value
),
DECODE (sql_hash_value, 0, prev_sql_addr, sql_address)
FROM v$session b
WHERE b.paddr = (SELECT addr
FROM v$process c
WHERE c.spid = TO_NUMBER ('&pid', 'xxxx')))
ORDER BY piece ASC
http://docs.oracle.com/cd/B19306_01/server.102/b14237/dynviews_2088.htm
http://junsansi.itpub.net/post/29894/292372