io.trino.cost.CachingTableStatsProvider Maven / Gradle / Ivy
/*
* 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 io.trino.cost;
import com.google.common.collect.ImmutableMap;
import io.trino.Session;
import io.trino.metadata.Metadata;
import io.trino.metadata.TableHandle;
import io.trino.spi.statistics.TableStatistics;
import java.util.Map;
import java.util.WeakHashMap;
import static java.util.Objects.requireNonNull;
public class CachingTableStatsProvider
implements TableStatsProvider
{
private final Metadata metadata;
private final Session session;
private final Map cache = new WeakHashMap<>();
public CachingTableStatsProvider(Metadata metadata, Session session)
{
this.metadata = requireNonNull(metadata, "metadata is null");
this.session = requireNonNull(session, "session is null");
}
@Override
public TableStatistics getTableStatistics(TableHandle tableHandle)
{
TableStatistics stats = cache.get(tableHandle);
if (stats == null) {
stats = metadata.getTableStatistics(session, tableHandle);
cache.put(tableHandle, stats);
}
return stats;
}
public Map getCachedTableStatistics()
{
return ImmutableMap.copyOf(cache);
}
}