TableLayoutResult.java
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.metadata;
import com.facebook.presto.common.predicate.Domain;
import com.facebook.presto.common.predicate.TupleDomain;
import com.facebook.presto.spi.ColumnHandle;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import static com.google.common.base.Preconditions.checkArgument;
import static java.util.Objects.requireNonNull;
public class TableLayoutResult
{
private final TableLayout layout;
private final TupleDomain<ColumnHandle> unenforcedConstraint;
public TableLayoutResult(TableLayout layout, TupleDomain<ColumnHandle> unenforcedConstraint)
{
this.layout = requireNonNull(layout, "layout is null");
this.unenforcedConstraint = requireNonNull(unenforcedConstraint, "unenforcedConstraint is null");
}
public TableLayout getLayout()
{
return layout;
}
public TupleDomain<ColumnHandle> getUnenforcedConstraint()
{
return unenforcedConstraint;
}
public static TupleDomain<ColumnHandle> computeEnforced(TupleDomain<ColumnHandle> predicate, TupleDomain<ColumnHandle> unenforced)
{
if (predicate.isNone()) {
// If the engine requests that the connector provides a layout with a domain of "none". The connector can have two possible reactions, either:
// 1. The connector can provide an empty table layout.
// * There would be no unenforced predicate, i.e., unenforced predicate is TupleDomain.all().
// * The predicate was successfully enforced. Enforced predicate would be same as predicate: TupleDomain.none().
// 2. The connector can't/won't.
// * The connector would tell the engine to put a filter on top of the scan, i.e., unenforced predicate is TupleDomain.none().
// * The connector didn't successfully enforce anything. Therefore, enforced predicate would be TupleDomain.all().
if (unenforced.isNone()) {
return TupleDomain.all();
}
if (unenforced.isAll()) {
return TupleDomain.none();
}
throw new IllegalArgumentException();
}
// The engine requested the connector provides a layout with a non-none TupleDomain.
// A TupleDomain is effectively a list of column-Domain pairs.
// The connector is expected enforce the respective domain entirely on none, some, or all of the columns.
// 1. When the connector could enforce none of the domains, the unenforced would be equal to predicate;
// 2. When the connector could enforce some of the domains, the unenforced would contain a subset of the column-Domain pairs;
// 3. When the connector could enforce all of the domains, the unenforced would be TupleDomain.all().
// In all 3 cases shown above, the unenforced is not TupleDomain.none().
checkArgument(!unenforced.isNone());
Map<ColumnHandle, Domain> predicateDomains = predicate.getDomains().get();
Map<ColumnHandle, Domain> unenforcedDomains = unenforced.getDomains().get();
ImmutableMap.Builder<ColumnHandle, Domain> enforcedDomainsBuilder = ImmutableMap.builder();
for (Map.Entry<ColumnHandle, Domain> entry : predicateDomains.entrySet()) {
ColumnHandle predicateColumnHandle = entry.getKey();
if (unenforcedDomains.containsKey(predicateColumnHandle)) {
checkArgument(
entry.getValue().equals(unenforcedDomains.get(predicateColumnHandle)),
"Enforced tuple domain cannot be determined. The connector is expected to enforce the respective domain entirely on none, some, or all of the column.");
}
else {
enforcedDomainsBuilder.put(predicateColumnHandle, entry.getValue());
}
}
Map<ColumnHandle, Domain> enforcedDomains = enforcedDomainsBuilder.build();
checkArgument(
enforcedDomains.size() + unenforcedDomains.size() == predicateDomains.size(),
"Enforced tuple domain cannot be determined. Connector returned an unenforced TupleDomain that contains columns not in predicate.");
return TupleDomain.withColumnDomains(enforcedDomains);
}
}