
208 Large Scale and Big Data
for example, marking the bits corresponding to the property vendor and price in
Figure 6.10c. After processing all triples in a group, if the local BitSet (locBitSet)
does not match the global BitSet (ECBitSet), the structure is incomplete and
the group of triples is eliminated (line 4). Figure 6.10d shows that locBitSet of
triplegroup tg
3
is not matched with any global bit patterns representing the two
star patterns; therefore, tg
3
is discarded.
Algorithm 6.2: POTGJoinAnnotator
Map (key:null, val: RDFMap rMap) ;
1i
f join on Sub then
joinKey rMap.Sub ;
else if join on Obj then
joinKey extract joinKey from rMap.pr