随着資料量的增加,Oracle資料庫分頁存儲過程(使用rownum分頁)查詢性能越來越差,查詢時間也越來越長,于是優化勢在必行,結合使用者一般使用特點(一般看前幾頁的較多),于是以此為切入點優化原先的存儲過程,在WHERE條件中增加rownum<=pageindex*pageSize,減少首次過濾的資料量,調整後的存儲過程如下:
CREATE OR REPLACE PACKAGE DotNet is
TYPE type_cur IS REF CURSOR; --定義遊标變量用于傳回記錄集
PROCEDURE DotNetPagination(Pindex in number, --分頁索引
Psql in varchar2, --産生dataset的sql語句
Psize in number, --頁面大小
v_cur out type_cur --傳回目前頁資料記錄
);
procedure DotNetPageRecordsCount(Psqlcount in varchar2, --産生dataset的sql語句
Prcount out number --傳回記錄總數
);
end DotNet;
CREATE OR REPLACE PACKAGE BODY DotNet is
PROCEDURE DotNetPagination(Pindex in number,
Psql in varchar2,
Psize in number,
v_cur out type_cur) AS
v_sql VARCHAR2(4000);
v_count number;
v_Plow number;
v_Phei number;
v_Appsql varchar2(1000);
Begin
v_Phei := Pindex * Psize + Psize;
v_Plow := v_Phei - Psize + 1;
--優化的地方--------------
v_Appsql := '';
if (Pindex < 1000) then
v_Appsql := ' and rownum <= ' || v_Phei;
end if;
v_sql := 'select * from (' || Psql || v_Appsql ||
') where rn between ' || v_Plow || ' and ' || v_Phei;
----------------------------
--原方法v_sql := 'select * from (' || Psql || ') where rn between ' || v_Plow || ' and ' || v_Phei;
open v_cur for v_sql;
End DotNetPagination;
procedure DotNetPageRecordsCount(Psqlcount in varchar2,
Prcount out number) as
v_sql varchar2(4000);
v_prcount number;
begin
v_sql := 'select count(*) from (' || Psqlcount || ')';
execute immediate v_sql
into v_prcount;
Prcount := v_prcount;
end DotNetPageRecordsCount;
end DotNet;
經測試,性能增加幾十倍以上
如SQL語句: select * from tb where date between to_date('2011-7-1','yyyy-mm-dd') and to_date('2011-8-1','yyyy-mm-dd') 查詢結果有100W記錄,原分頁存儲過程取某一頁的資料用時100秒以上,優化後的存儲過程時間可以縮小到零點幾秒