sql優化實戰:從6秒+到2秒(使用索引)
阿新 • • 發佈:2019-01-07
今天客服反饋 客戶在前兩天查詢一個移動端報表時報錯了。
我看了一下報錯資訊,大致是timeout,這種錯誤基本可以確定是由於查詢時間超過閥值(一般為3秒)。
sql程式碼如下:
執行時間:大概是6秒。SELECT hh.EMP_ID , hh.STORE_ID , hh.pn1 , SUM(hh.numb) numb , SUM(hh.SJ) sj , NULL zb FROM ( SELECT po.EMP_ID , v.STORE_ID , v.UPLOAD_DATE , i.PN1 , CAST(iv.ITEM1 AS NUMERIC) numb , CAST(iv.ITEM1 AS NUMERIC) * CAST(p.PRICE AS NUMERIC(10, 2)) SJ FROM TB_DR v WITH ( NOLOCK ) INNER HASH JOIN TB_DR_ITEM iv WITH ( NOLOCK ) ON iv.MAIN_ID = v.ID INNER JOIN tb_org o WITH ( NOLOCK ) ON v.emp_id = o.emp_id INNER JOIN tb_org po WITH ( NOLOCK ) ON po.org_ID = o.PARENT_ORG_ID INNER JOIN tb_PROD p WITH ( NOLOCK ) ON p.PROD_ID = iv.PROD_ID INNER JOIN tb_DI i WITH ( NOLOCK ) ON i.DICT_ITEM_ID = p.BRAND_ID WHERE LEFT(v.bdate, 7) = CONVERT(VARCHAR(7), GETDATE(), 120) AND v.CODE IN ( 'SB001', 'SB002','SB003') AND po.emp_id = 12345 ) hh GROUP BY hh.EMP_ID , hh.STORE_ID , hh.pn1
表資訊:tb_dr大概是500w條,tb_dr_item大概是2800w條資料,其他的表基本上都是幾千條。
結果集:大致返回50條。
優化:由於tb_dr已有bdate欄位的索引,沒有看執行計劃,但是由於 left 函式作用在bdate,導致這個索引用不上,同時考慮到tb_dr和tb_dr_item表主表-子表,子表通過main_id和主表的id關聯,所以在join時不應該用hash,就算要用也應該是loop,所以改為:
SELECT hh.EMP_ID , hh.STORE_ID , hh.pn1 , SUM(hh.numb) numb , SUM(hh.SJ) sj , NULL zb FROM ( SELECT po.EMP_ID , v.STORE_ID , v.UPLOAD_DATE , i.PN1 , CAST(iv.ITEM1 AS NUMERIC) numb , CAST(iv.ITEM1 AS NUMERIC) * CAST(p.PROD_PRICE AS NUMERIC(10, 2)) SJ FROM TB_R v WITH ( NOLOCK ) INNER HASH JOIN TB_DR_ITEM iv WITH ( NOLOCK ) ON iv.MAIN_ID = v.ID INNER JOIN tb_org o WITH ( NOLOCK ) ON v.emp_id = o.emp_id INNER JOIN tb_org po WITH ( NOLOCK ) ON po.org_ID = o.PARENT_ORG_ID INNER JOIN tb_PROD p WITH ( NOLOCK ) ON p.PROD_ID = iv.PROD_ID INNER JOIN tb_DI i WITH ( NOLOCK ) ON i.DICT_ITEM_ID = p.BRAND_ID WHERE v.bdate like CONVERT(VARCHAR(7), GETDATE(), 120) +'%' AND v.FUNC_CODE IN ( 'TB_006', 'TB_006_AT05', 'TB_006_AT06', 'TB_006_AT07', 'TB_006_AT08', 'TB_005_AT02', 'TB_005_AT03', 'TB_005_AT04', 'TB_005_AT05', 'TB_005_AT06', 'TB_005_AT07', 'TB_005_AT08', 'TB_005_AT09' ) AND po.emp_id = 12345 ) hh GROUP BY hh.EMP_ID , hh.STORE_ID , hh.pn1
其中最主要的是把LEFT(v.bdate, 7) = CONVERT(VARCHAR(7), GETDATE(), 120) 改為 v.biz_date like CONVERT(VARCHAR(7), GETDATE(), 120) +'%',這樣索引就能用上了。
查詢速度從6秒降為2秒。