問題描述
以下問題的答案是 C 使用 FORCESEEK 提示.但是，要使用提示，我們必須先查看執行計劃，對嗎?這個問題沒有提到任何關于執行計劃的內容.問題似乎是讀者阻止作家".那么，在這種情況下，快照隔離不會有幫助嗎?
The said answer for the following question is C to use FORCESEEK hint. But, to use hint, we have to review the execution plan first, right? The question doesn't mention anything about execution plan. The problem seems to be "Readers block Writers". So, won't SNAPSHOT ISOLATION help in this kind of situation?
問題:由于對具有聚集索引的頻繁更新表進行查詢，數據庫應用程序運行緩慢.該查詢返回四列:包含在非聚集索引中的 where 子句中的三列和一個附加列.優化語句
Question: A database application runs slowly because of a query against a frequently updated table that has a clustered index. The query returns four columns: three columns in its where clause contained in a non-clustered index and one additional column. To optimize the statement
- A.向查詢添加 HASH 提示
- B.向查詢添加 LOOP 提示
- C.向查詢添加 FORCESEEK 提示
- D.向索引添加 INCLUDE 子句
- E.向附加查詢添加 FORCESCAN 提示
- F.添加列存儲索引以覆蓋查詢
- G.啟用優化臨時工作負載選項.
- H.將唯一聚集索引與列存儲索引轉換.
- 我.在運行查詢之前包含 SET FORCEPLAN ON 語句
- J.在運行查詢之前包含 SET STATISTICS PROFILE ON 語句
- K.在運行查詢之前包含 SET STATISTICS SHOWPLAN_XML ON 語句
- L.在運行查詢之前包含 SET TRANSACTION ISOLATION LEVEL REPEATABLE READ 語句
- M.在運行查詢之前包含 SET TRANSADCTION ISOLATION LEVEL SNAPSHOT 語句
- N.在運行查詢之前包含 SET TRANSACTION ISOLATION LEVEL SERIALIZABLE 語句
推薦答案
我會選擇選項 D.因為它涵蓋了表中缺失的非聚集索引.
I will go for option D. because it covers the missing non-Clusterd Index on the table.
這篇關于這些事實是否真的暗示要使用 FORCESEEK?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！