private PlanNode planTableScan(TableScanNode node, Expression predicate, Context context) {
DomainTranslator.ExtractionResult decomposedPredicate =
DomainTranslator.fromPredicate(metadata, session, predicate, symbolAllocator.getTypes());
TupleDomain<ColumnHandle> simplifiedConstraint =
decomposedPredicate
.getTupleDomain()
.transform(node.getAssignments()::get)
.intersect(node.getCurrentConstraint());
checkState(node.getOutputSymbols().containsAll(context.getLookupSymbols()));
Set<ColumnHandle> lookupColumns =
context
.getLookupSymbols()
.stream()
.map(node.getAssignments()::get)
.collect(toImmutableSet());
Set<ColumnHandle> outputColumns =
node.getOutputSymbols()
.stream()
.map(node.getAssignments()::get)
.collect(toImmutableSet());
Optional<ResolvedIndex> optionalResolvedIndex =
metadata.resolveIndex(
session, node.getTable(), lookupColumns, outputColumns, simplifiedConstraint);
if (!optionalResolvedIndex.isPresent()) {
// No index available, so give up by returning something
return node;
}
ResolvedIndex resolvedIndex = optionalResolvedIndex.get();
Map<ColumnHandle, Symbol> inverseAssignments =
ImmutableBiMap.copyOf(node.getAssignments()).inverse();
PlanNode source =
new IndexSourceNode(
idAllocator.getNextId(),
resolvedIndex.getIndexHandle(),
node.getTable(),
node.getLayout(),
context.getLookupSymbols(),
node.getOutputSymbols(),
node.getAssignments(),
simplifiedConstraint);
Expression resultingPredicate =
combineConjuncts(
DomainTranslator.toPredicate(
resolvedIndex.getUnresolvedTupleDomain().transform(inverseAssignments::get)),
decomposedPredicate.getRemainingExpression());
if (!resultingPredicate.equals(TRUE_LITERAL)) {
// todo it is likely we end up with redundant filters here because the predicate push down
// has already been run... the fix is to run predicate push down again
source = new FilterNode(idAllocator.getNextId(), source, resultingPredicate);
}
context.markSuccess();
return source;
}
