出現Lock-Wait鎖等待，怎麼解決
阿新 • • 發佈：2018-12-31
C:\>db2 update monitor switches using lock on
C:\>db2 get snapshot for locks on datcmg | more
Locks:
Address TranHdl Lockname Type Mode Sts Owner Dur HoldCount Att ReleaseFlg
0x070000002F7B6B40 43 0002010C0000000077A3000252 Row .NS G 43 1 0 0x00 0x00000001
0x07000000302241C0 23 0002010C0000000077A3000252 Row ..X W 43 1 0 0x00 0x40000000
//事物23被事物43鎖了
Transactions:
Address AppHandl [nod-index] TranHdl Locks State Tflag Tflag2 Firstlsn Lastlsn LogSpace SpaceReserved TID AxRegCnt GXID ClientUserID ClientWrkstnName ClientApplName ClientAccntng
0x0700000020326500 22334 [000-22334] 23 4 READ 0x00000000 0x00000000 0x000000000000 0x000000000000 0 0 0x000000A1B3E7 1 0 n/a JYKL0 n/a n/a
0x0700000020339B00 22322 [000-22322] 43 29 READ 0x00000000 0x00000000 0x000000000000 0x000000000000 0 0 0x000000A1AFE5 1 0 n/a JYKL0 n/a n/a
//事物23關聯應用22334，事物43關聯應用22322
Applications:
Address AppHandl [nod-index] NumAgents CoorEDUID Status C-AnchID C-StmtUID L-AnchID L-StmtUID Appid
0x0780000001070080 22334 [000-22334] 1 26791 Lock-wait 53 5393 243 7524 182.100.100.50.51075.1002010812
0x0780000001203260 22322 [000-22322] 1 6427 UOW-Waiting 0 0 188 7426 182.100.100.50.51023.1002010812
//通過sql座標可以定位鎖sql和被鎖sql
Dynamic SQL Statements:
Address AnchID StmtUID NumEnv NumVar NumRef NumExe Text
0x070000002F019680 53 5393 1 1 13 13 DELETE FROM LJSGetDraw WHERE
GetNoticeNo = ? AND PolNo = ? AND DutyCode = ? AND GetDutyKind = ? AND GetDutyCode = ? AND Currency = ?
0x070000003A28CBE0 188 7426 1 1 1 1 SELECT * FROM LJSGetDraw a
WHERE not exists(select 'X' from LJAGetDraw where PolNo=a.PolNo and DutyCode=a.DutyCode and GetDutyCode=a.GetDutyCode and
GetDutyKind=a.GetDutyKind and GetNoticeNo=a.GetNoticeNo) and GetDate<=date('2010-01-29') and nvl(ComeFlag,'x')<>'1' and
RReportFlag='0' and (not exists(select 1 from lccontstate where PolNo=a.PolNo and statetype='Available' and state='1' and
enddate is null) and not exists(select 'X' from lcconthangupstate where contno =a.contno and hanguptype='2' ) and
exists(select 'X' from LCPol where PolNo=a.PolNo and AppFlag='1' ) or exists (select 'x' from LMDutyGetAlive where
MAXGETCOUNTTYPE='0' and GETDUTYCODE=a.GETDUTYCODE))
//WebSphere的jndi連線池自動設定高級別的db2隔離級別
不同一個數據庫連線的事物會有隔離級別的控制，在本地連線db2級別低，但是WebSphere的jndi連線池自動設定高級別的db2隔離級別，
所以在長時間使用sql語句的時候，需要手工設定隔離級別為最低ur，來避免鎖。
具體修改是在需要進行操作的sql語句後面加上事物的級別
eg:db2 select * from User with ur，對於不是使用sql語句的寫法可以改成JDBC操作。
所有sql都手工設定隔離級別ur
死鎖監控器：
9.建立一個針對死鎖的event monitor
db2 "create event monitor dlmon for deadlocks with details write to file '/home/db2inst1/evmon'";
db2 set event monitor dlmon state 1;啟用
db2evmon -db datcmg -evm dlmon >/home/db2inst1/檔名
sql語句效能建議：
(請注意用相應db2使用者telnet)
db2adivs -d dbname -i 1.sql>/home/db2inst1/檔名
抓快照：
db2 get snapshot for db on datcmg > /home/db2inst1/檔名
sql語句慢的快照：
db2 get snapshot for dynamic sql on sample
查詢執行慢的sql：
select * from sysibmadm.top_dynamic_sql order by average_execution_time_s desc
C:\>db2 get snapshot for locks on datcmg | more
Locks:
Address TranHdl Lockname Type Mode Sts Owner Dur HoldCount Att ReleaseFlg
0x070000002F7B6B40 43 0002010C0000000077A3000252 Row .NS G 43 1 0 0x00 0x00000001
0x07000000302241C0 23 0002010C0000000077A3000252 Row ..X W 43 1 0 0x00 0x40000000
//事物23被事物43鎖了
Transactions:
Address AppHandl [nod-index] TranHdl Locks State Tflag Tflag2 Firstlsn Lastlsn LogSpace SpaceReserved TID AxRegCnt GXID ClientUserID ClientWrkstnName ClientApplName ClientAccntng
0x0700000020326500 22334 [000-22334] 23 4 READ 0x00000000 0x00000000 0x000000000000 0x000000000000 0 0 0x000000A1B3E7 1 0 n/a JYKL0 n/a n/a
0x0700000020339B00 22322 [000-22322] 43 29 READ 0x00000000 0x00000000 0x000000000000 0x000000000000 0 0 0x000000A1AFE5 1 0 n/a JYKL0 n/a n/a
//事物23關聯應用22334，事物43關聯應用22322
Applications:
Address AppHandl [nod-index] NumAgents CoorEDUID Status C-AnchID C-StmtUID L-AnchID L-StmtUID Appid
0x0780000001070080 22334 [000-22334] 1 26791 Lock-wait 53 5393 243 7524 182.100.100.50.51075.1002010812
0x0780000001203260 22322 [000-22322] 1 6427 UOW-Waiting 0 0 188 7426 182.100.100.50.51023.1002010812
//通過sql座標可以定位鎖sql和被鎖sql
Dynamic SQL Statements:
Address AnchID StmtUID NumEnv NumVar NumRef NumExe Text
0x070000002F019680 53 5393 1 1 13 13 DELETE FROM LJSGetDraw WHERE
GetNoticeNo = ? AND PolNo = ? AND DutyCode = ? AND GetDutyKind = ? AND GetDutyCode = ? AND Currency = ?
0x070000003A28CBE0 188 7426 1 1 1 1 SELECT * FROM LJSGetDraw a
WHERE not exists(select 'X' from LJAGetDraw where PolNo=a.PolNo and DutyCode=a.DutyCode and GetDutyCode=a.GetDutyCode and
GetDutyKind=a.GetDutyKind and GetNoticeNo=a.GetNoticeNo) and GetDate<=date('2010-01-29') and nvl(ComeFlag,'x')<>'1' and
RReportFlag='0' and (not exists(select 1 from lccontstate where PolNo=a.PolNo and statetype='Available' and state='1' and
enddate is null) and not exists(select 'X' from lcconthangupstate where contno =a.contno and hanguptype='2' ) and
exists(select 'X' from LCPol where PolNo=a.PolNo and AppFlag='1' ) or exists (select 'x' from LMDutyGetAlive where
MAXGETCOUNTTYPE='0' and GETDUTYCODE=a.GETDUTYCODE))
//WebSphere的jndi連線池自動設定高級別的db2隔離級別
不同一個數據庫連線的事物會有隔離級別的控制，在本地連線db2級別低，但是WebSphere的jndi連線池自動設定高級別的db2隔離級別，
所以在長時間使用sql語句的時候，需要手工設定隔離級別為最低ur，來避免鎖。
具體修改是在需要進行操作的sql語句後面加上事物的級別
eg:db2 select * from User with ur，對於不是使用sql語句的寫法可以改成JDBC操作。
所有sql都手工設定隔離級別ur
死鎖監控器：
9.建立一個針對死鎖的event monitor
db2 "create event monitor dlmon for deadlocks with details write to file '/home/db2inst1/evmon'";
db2 set event monitor dlmon state 1;啟用
db2evmon -db datcmg -evm dlmon >/home/db2inst1/檔名
sql語句效能建議：
(請注意用相應db2使用者telnet)
db2adivs -d dbname -i 1.sql>/home/db2inst1/檔名
抓快照：
db2 get snapshot for db on datcmg > /home/db2inst1/檔名
sql語句慢的快照：
db2 get snapshot for dynamic sql on sample
查詢執行慢的sql：
select * from sysibmadm.top_dynamic_sql order by average_execution_time_s desc