ORACLE快速?gòu)氐譑ill掉的會(huì)話,防止鎖表

2020-05-30

編程之家收集整理的這篇文章主要介紹了ORACLE快速?gòu)氐譑ill掉的會(huì)話,防止鎖表，編程之家小編覺得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。

萬(wàn)能是sql重啟服務(wù)，不然，以下之：

在ORACLE數(shù)據(jù)庫(kù)當(dāng)中，有時(shí)候會(huì)使用ALTER SYSTEM KILL SESSION 'sid,serial#'殺掉一個(gè)會(huì)話進(jìn)程，但是使用這個(gè)sql語(yǔ)句殺掉會(huì)話后，數(shù)據(jù)庫(kù)并不會(huì)立即釋放掉相關(guān)的資源，有時(shí)候你會(huì)發(fā)現(xiàn)鎖定的資源很長(zhǎng)時(shí)間也不會(huì)釋放，即使會(huì)話狀態(tài)為“KILLED”，依然會(huì)阻塞其它會(huì)話。

下面根據(jù)Eygel的"Oracle中Kill session的研究"，構(gòu)造一個(gè)案例看看kill session到底做了什么。如下所示

會(huì)話1：

Connected.

sql> update test set status='invalid';

55944 rows updated.

sql> update test2 set dropped='Y';

3090 rows updated.

會(huì)話2：

user

USER is "SYS"

update etl.test2 3090 會(huì)話3

select saddr,sid,serial#,paddr,username,status from v$session where username =upper('etl') or username ='sys');

SADDR SID SERIAL# PADDR USERNAME STATUS

---------------- ---------- ---------- ---------------- ------------------------------ --------

000000025C233B00 27 33353 000000025F1D1FC8 ETL INACTIVE

000000025C23A608 37 11448 000000025F1D27B0 SYS ACTIVE

000000025C24BC50 63 54311 000000025F1D5F08 SYS ACTIVE

alter system kill '27,33353';

System altered.

SADDR SID SERIAL# PADDR USERNAME STATUS

--------------000000025C233B00 27 33353 000000025C21A0B0 ETL KILLED

000000025C23A608 37 11448 000000025F1D27B0 SYS ACTIVE

000000025C24BC50 63 54311 000000025F1D5F08 SYS INACTIVE

如下所示，我殺掉了其中兩個(gè)會(huì)話后，這兩個(gè)會(huì)話的地址都變?yōu)?00000025C21A0B0了(請(qǐng)見PADDR列)。當(dāng)在Oracle中kill session以后,Oracle只是簡(jiǎn)單的把相關(guān)session的paddr 指向同一個(gè)虛擬地址.此時(shí)v$process和v$session失去關(guān)聯(lián),進(jìn)程就此中斷。然后Oracle就等待PMON去清除這些Session.所以通常等待一個(gè)被標(biāo)記為Killed的Session退出需要花費(fèi)很長(zhǎng)的時(shí)間.如果此時(shí)被Kill的process，重新嘗試執(zhí)行任務(wù)，那么馬上會(huì)收到進(jìn)程中斷的提示，process退出，此時(shí)Oracle會(huì)立即啟動(dòng)PMON來(lái)清除該session.這被作為一次異常中斷處理.

'63,54311';

000000025C233B00 27 33353 000000025C21A0B0 ETL KILLED

000000025C24BC50 63 54311 000000025C21A0B0 SYS KILLED

我們根據(jù)下面sql找到進(jìn)程的地址，然后在v$process里面找到對(duì)應(yīng)的spid,然后從操作系統(tǒng)中殺掉該進(jìn)程。

select p.addr from v$process p where pid <> 1

2 minus

3 select s.paddr session s;

ADDR

--

000000025F1D1FC8

000000025F1D5F08

session

000000025C24BC50 63 54311 000000025C21A0B0 SYS KILLED

select addr,pid,spid,username from v$process where addr in ('000000025F1D1FC8','000000025F1D5F08');

ADDR PID SPID USERNAME

-- ---------- ------------ ---------------

000000025F1D1FC8 22 12959 oracle

000000025F1D5F08 38 12971 oracle

sql> ! kill -9 12959

kill -9 12971

000000025C23A608 37 11448 000000025F1D27B0 SYS ACTIVE

在ORACLE數(shù)據(jù)庫(kù)殺掉會(huì)話進(jìn)程有三種方式：

1： ALTER SYSTEM KILL SESSION

關(guān)于KILL SESSION Clause ，如下官方文檔描述所示，alter system kill session實(shí)際上不是真正的殺死會(huì)話，它只是將會(huì)話標(biāo)記為終止。等待PMON進(jìn)程來(lái)清除會(huì)話。

The KILL SESSION clause lets you mark a session as terminated,roll back ongoing transactions,release all session locks,and partially recover session resources. To use this clause,your instance must have the database open. Your session and the session to be terminated must be on the same instance unless you specify integer3.You must identify the session with the following values from the V$SESSION view:

For integer1,specify the value of the SID column.

For integer2,specify the value of the SERIAL# column.

For the optional integer3,specify the ID of the instance where the target session to be killed exists. You can find the instance ID by querying the GV$ tables.

If the session is performing some activity that must be completed,such as waiting for a reply from a remote database or rolling back a transaction,255)">then Oracle Database waits for this activity to complete,marks the session as terminated,and then returns control to you. If the waiting lasts a minute,255)">then Oracle Database marks the session to be terminated and returns control to you with a message that the session is marked to be terminated. The PMON background process then marks the session as terminated when the activity is complete.

Whether or not the session has an ongoing transaction,Oracle Database does not recover the entire session state until the session user issues a request to the session and receives a message that the session has been terminated.

可以使用ALTER SYSTEM KILL SESSION 'sid,serial#' IMMEDIATE 來(lái)快速回滾事物、釋放會(huì)話的相關(guān)鎖、立即返回當(dāng)前會(huì)話的控制權(quán)。

Specify IMMEDIATE to instruct Oracle Database to roll back ongoing transactions,recover the entire session state,and return control to you immediately.

2： ALTER SYSTEM DISCONNECT SESSION

ALTER SYSTEM DISCONNECT SESSION 殺掉專用服務(wù)器(DEDICATED SERVER)或共享服務(wù)器的連接會(huì)話，它等價(jià)于從操作系統(tǒng)殺掉進(jìn)程。它有兩個(gè)選項(xiàng)POST_TRANSACTION和IMMEDIATE， 其中POST_TRANSACTION表示等待事務(wù)完成后斷開會(huì)話，IMMEDIATE表示中斷會(huì)話，立即回滾事務(wù)。

sql> ALTER SYSTEM DISCONNECT SESSION 'sid,serial#' POST_TRANSACTION;

3： KILL -9 SPID (Linux) 或 orakill ORACLE_SID spid　(Windows)

可以使用下面sql語(yǔ)句找到對(duì)應(yīng)的操作系統(tǒng)進(jìn)程SPID，然后殺掉。當(dāng)然殺掉操作系統(tǒng)進(jìn)程是一件危險(xiǎn)的事情，尤其不要誤殺。所以在執(zhí)行前，一定要謹(jǐn)慎確認(rèn)。

SET LINESIZE 100

COLUMN spid FORMAT A10

COLUMN username FORMAT A10

COLUMN program FORMAT A45

SELECT s.inst_id,

s.sid,244)"> s.serial#,monospace; width:878.046875px; padding:0px; direction:ltr; line-height:12pt; background-color:white"> p.spid,244)"> s.username,monospace; width:878.046875px; padding:0px; direction:ltr; line-height:12pt; background-color:white"> s.program

FROM gv$session s

JOIN gv$process p ON p.addr = s.paddr AND p.inst_id = s.inst_id

WHERE s.type != 'BACKGROUND';

總結(jié)

以上是生活随笔為你收集整理的oracle锁表会话超时时间,ORACLE快速彻底Kill掉的会话,防止锁表的全部?jī)?nèi)容，希望文章能夠幫你解決所遇到的問(wèn)題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯(cuò)，歡迎將生活随笔推薦給好友。