How to remove Hash Join
> When I create Index, should I create index on Indivisual FK Column as below?Yes individual indexes because that is how they are used in JOIN ON clauses.Covering index is mostly good for the target...
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@Kalman,Thanks for your answer. I wanted to ask you how to choose Indexes on Foreign Keys? Quesiton #1Let's say There is dbo.Mytable with 30 column and 4 of them are foreign keys. When I create Index,...
View ArticleHow to remove Hash Join
Hash joins are best for joins, if you really want to remove hash join create index on the joining column and it will be index join and performance will be bad. Refer below link for more on hash join...
View ArticleHow to remove Hash Join
If you are running a fully optimized system, you never have to look at hash joins.Do you have indexes on all FOREIGN KEYs and WHERE condition columns?Are indexes rebuilt (REBUILD) every weekend?Are...
View ArticleHow to remove Hash Join
This is what I am looking for. How do you know you have to create these indexes and what are the columns to be included in the index?The critical columns in the index keys are those specified in the...
View ArticleHow to remove Hash Join
Normally you start from creating indexes on the column that is used in the JOIN condition. If you include columns which are used in the SELECT clause, you'll create covering index (as in this case).For...
View ArticleHow to remove Hash Join
@Naomi,Thanks for your response. I am looking to create indexes/anythign else such a way that query execution plan would show me merger/Loop join instead of hash join. Could you please guide me?
View ArticleHow to remove Hash Join
@Dan,Thanks for answering my question. This is what I am looking for. How do you know you have to create these indexes and what are the columns to be included in the index?After creating these indexes,...
View ArticleHow to remove Hash Join
Try creating indexes on OrderID:CREATE UNIQUE NONCLUSTERED INDEX idx_MyOrders ON dbo.MyOrders(OrderID) INCLUDE (OrderDate); CREATE NONCLUSTERED INDEX idx_MyOrderDetails ON dbo.MyOrderDetails(OrderID)...
View ArticleHow to remove Hash Join
This will force a merge join:--Hash Join SELECT O.OrderID, O.OrderDate, OD.ProductID, OD.Quantity FROM dbo.MyOrders AS O INNER MERGE JOIN dbo.MyOrderDetails AS OD ON O.OrderID = OD.OrderID"Premature...
View ArticleHow to remove Hash Join
Check Use an OUTER LOOP JOIN for faster performance when one of the tables is much smallerFor every expert, there is an equal and opposite expert. - Becker's LawMy blog
View ArticleHow to remove Hash Join
Hi there,I want to know the technique / basic strategy to replace Hash join by Merge/Loop join. Could you please tell me how to remove following Hash join? How would I approach the problem?Use...
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