Data Mismatch on WHERE Clause might Cause Serious Performance Problems

Like Applying Function on WHERE clause problem, any datatype mismatch on WHERE clause might cause serious performance problems. Predicates on both sides of comparisons (for example on WHERE clause) always must match datatypes. It means that if the left side of predicate is integer than the right side needs to be integer. If the datatypes…

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Indexes Overhead on DML (Insert-Update-Delete) Operations

Indices dramatically affect query performance. A report which can take several hours can be completed in just a few seconds with a proper index. On the other hand every index might affect DML (Insert-Update-Delete) operations, because every DML operation touches clustered index and every related nonclustered index. To be able to see this effect I…

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