Databases 11

Cost of the query

• (A, B, C)
• (D, F, E)
• (G, H)

Calculate output size of

• Output size of is
• Output size of is

Let the previous output be of size Both joins are hash joins, calculate cost of the query

• Cost of join on is
• Cost of selection is , it is pipelined
• Cost of join on is

Total cost is

Sorted clustered index on , first join is a nested join loop, second join is a sort merge join

• Cost of join on is
• Cost of selection is again 0
• Cost of join on is

Total cost is

Sorted clustered index on and on , both joins are sort-merge joins

• Cost of join on is
• Cost of selection is again 0
• Cost of join on is

Total cost is

---

• (A, B, C)
• (D, E)

Calculate output size of

• Output size of is
• Output size of is

Let the previous output be of size Calculate cost of the query given both joins are nested loop joins

• Cost of selection is
• Cost of join on is
• Cost of join on is

Total cost is

Sorted clustered index on , both joins are hash joins

• Cost of selection is
• Cost of join on is
• Cost of join on is

Total cost is