Oracle 10g對DBWR的SCAN間隔進行了調整
2024-08-29 13:49:58
供稿：網友
了避免DBWR不必要的喚醒及過于活躍,從Oracle10g開始,Oracle對DBWR的SCAN間隔進行了調整.
在內部由一個隱含參數:_dbwr_scan_interval 控制.Oracle9i中這個參數缺省值為10 s: SQL> select * from v$version 2 /
BANNER----------------------------------------------------------------Oracle9i EnterPRise Edition Release 9.2.0.4.0 - 64bit ProdUCtionPL/SQL Release 9.2.0.4.0 - ProductionCORE 9.2.0.3.0 ProductionTNS for Solaris: Version 9.2.0.4.0 - ProductionNLSRTL Version 9.2.0.4.0 - Production
SQL> col ksppinm for a20SQL> col ksppdesc for a40SQL> col ksppstvl for a10SQL> select 2 ksppinm,ksppdesc,ksppstvl 3 from 4 sys.x$ksppi x, 5 sys.x$ksppcv y 6 where 7 x.inst_id = userenv('Instance') and 8 y.inst_id = userenv('Instance') and 9 x.indx = y.indx and 10 x.ksppinm like '%_dbwr_scan%' 11 /
KSPPINM KSPPDESC KSPPSTVL-------------------- ---------------------------------------- ----------_dbwr_scan_interval dbwriter scan interval 10
從Oracle10g開始,此缺省值被調這個為300 s:SQL> select * from v$version 2 /
BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.1.0.3.0 - 64bipL/SQL Release 10.1.0.3.0 - ProductionCORE 10.1.0.3.0 ProductionTNS for Solaris: Version 10.1.0.3.0 - ProductionNLSRTL Version 10.1.0.3.0 - Production
SQL> col ksppinm for a20SQL> col ksppdesc for a40SQL> col ksppstvl for a10SQL> select 2 ksppinm,ksppdesc,ksppstvl 3 from 4 sys.x$ksppi x, 5 sys.x$ksppcv y 6 where 7 x.inst_id = userenv('Instance') and 8 y.inst_id = userenv('Instance') and 9 x.indx = y.indx and 10 x.ksppinm like '%_dbwr_scan%' 11 /
KSPPINM KSPPDESC KSPPSTVL-------------------- ---------------------------------------- ----------_dbwr_scan_interval dbwriter scan interval 300
在Oracle10gR2中,這個參數未作進一步調整,缺省值仍然為300:SQL> select * from v$version 2 /
BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - ProdPL/SQL Release 10.2.0.1.0 - ProductionCORE 10.2.0.1.0 ProductionTNS for linux: Version 10.2.0.1.0 - ProductionNLSRTL Version 10.2.0.1.0 - Production
SQL> col ksppinm for a20SQL> col ksppdesc for a40SQL> col ksppstvl for a10SQL> select 2 ksppinm,ksppdesc,ksppstvl 3 from 4 sys.x$ksppi x, 5 sys.x$ksppcv y 6 where 7 x.inst_id = userenv('Instance') and 8 y.inst_id = userenv('Instance') and 9 x.indx = y.indx and 10 x.ksppinm like '%_dbwr_scan%' 11 /
KSPPINM KSPPDESC KSPPSTVL-------------------- ---------------------------------------- ----------_dbwr_scan_interval dbwriter scan interval 300
以上內容,僅供參考.
