| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.cassandra.io.sstable; |
| |
| import org.apache.cassandra.io.sstable.format.SSTableReader; |
| import org.apache.cassandra.tracing.Tracing; |
| |
| /** |
| * Listener for receiving notifications associated with reading SSTables. |
| */ |
| public interface SSTableReadsListener |
| { |
| /** |
| * The reasons for skipping an SSTable |
| */ |
| enum SkippingReason |
| { |
| BLOOM_FILTER("Bloom filter allows skipping sstable {}"), |
| MIN_MAX_KEYS("Check against min and max keys allows skipping sstable {}"), |
| PARTITION_INDEX_LOOKUP("Partition index lookup allows skipping sstable {}"), |
| INDEX_ENTRY_NOT_FOUND("Partition index lookup complete (bloom filter false positive) for sstable {}"); |
| |
| private final String message; |
| |
| SkippingReason(String message) |
| { |
| this.message = message; |
| } |
| |
| public void trace(Descriptor descriptor) |
| { |
| Tracing.trace(message, descriptor.id); |
| } |
| } |
| |
| /** |
| * The reasons for selecting an SSTable |
| */ |
| enum SelectionReason |
| { |
| KEY_CACHE_HIT("Key cache hit for sstable {}, size = {}"), |
| INDEX_ENTRY_FOUND("Partition index found for sstable {}, size = {}"); |
| |
| private final String message; |
| |
| SelectionReason(String message) |
| { |
| this.message = message; |
| } |
| |
| public void trace(Descriptor descriptor, AbstractRowIndexEntry entry) |
| { |
| Tracing.trace(message, descriptor.id, entry.blockCount()); |
| } |
| } |
| |
| /** |
| * Listener that does nothing. |
| */ |
| static final SSTableReadsListener NOOP_LISTENER = new SSTableReadsListener() {}; |
| |
| /** |
| * Handles notification that the specified SSTable has been skipped during a single partition query. |
| * |
| * @param sstable the SSTable reader |
| * @param reason the reason for which the SSTable has been skipped |
| */ |
| default void onSSTableSkipped(SSTableReader sstable, SkippingReason reason) |
| { |
| } |
| |
| /** |
| * Handles notification that the specified SSTable has been selected during a single partition query. |
| * |
| * @param sstable the SSTable reader |
| * @param indexEntry the index entry |
| * @param reason the reason for which the SSTable has been selected |
| */ |
| default void onSSTableSelected(SSTableReader sstable, SelectionReason reason) |
| { |
| } |
| |
| /** |
| * Handles notification that the specified SSTable is being scanned during a partition range query. |
| * |
| * @param sstable the SSTable reader of the SSTable being scanned. |
| */ |
| default void onScanningStarted(SSTableReader sstable) |
| { |
| } |
| } |