Cost Estimation

Simple Cost Model

Materialized relation $R$ with an attribute $A$

• $|R|$ - Cardinality of $R$
• $b(R)$ - Blocking factor for index $R$
• min($R,A$) - Minimum value for $A$ in $R$
• max($R,A$) - Maximum value for $A$ in $R$
• distinct($R,A$) - Number of distinct values of $A$

Cost of Retrieval

Cost of Relational Operations

Size Estimation

Always Good Transformations

Join Order Selection