For each fragment of CUSTOMER (e.g., C_NYC = σ_city='NYC'(CUSTOMER) ), ORDER_NYC = ORDER ⋉ C_NYC (semijoin on cust_id).
Derived fragmentation: fragment ORDER based on the fragmentation of CUSTOMER . For each fragment of CUSTOMER (e
| Time | TX | TY | |------|----|----| | t1 | Lock stock at R1, R2 (write quorum) | | | t2 | Read stock: 100, 100 | | | t3 | Write stock: 90, 90 | | | t4 | Release locks | | | t5 | | Lock price at R2, R3 (write quorum) | | t6 | | Read price: $10, $10 | | t7 | | Write price: $10.50, $10.50 | | t8 | | Release locks | For each fragment of CUSTOMER (e.g.