Pipelined XPath Query Based on Cost Optimization

Table 1

Relation index.

Node	Index entry
A1	<1, CH>, <3, DS>, <4, DS>, <5, DS>, <6, CH>, <7, DS>, <9, DS>, <10, DS>, <11, DS>, <12, DS>, <13, DS>
B1	<2, AT>, <3, CH>, <4, DS>, <5, CH>
C1	<4, CH>
A2	<7, CH>, <9, DS>, <10, DS>, <11, DS>, <12, CH>, <13, CH>
B2	<8, AT>, <9, CH>, <10, DS>, <11, CH>
A3	<10, CH>