michaeljmarshall commented on code in PR #4353: URL: https://github.com/apache/cassandra/pull/4353#discussion_r2683599555
########## src/java/org/apache/cassandra/index/sai/disk/EmptyIndex.java: ########## @@ -0,0 +1,121 @@ +/* + * 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.index.sai.disk; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.List; + +import org.apache.cassandra.db.PartitionPosition; +import org.apache.cassandra.db.virtual.SimpleDataSet; +import org.apache.cassandra.dht.AbstractBounds; +import org.apache.cassandra.index.sai.QueryContext; +import org.apache.cassandra.index.sai.SSTableContext; +import org.apache.cassandra.index.sai.StorageAttachedIndex; +import org.apache.cassandra.index.sai.disk.v1.vector.PrimaryKeyWithScore; +import org.apache.cassandra.index.sai.iterators.KeyRangeIterator; +import org.apache.cassandra.index.sai.plan.Expression; +import org.apache.cassandra.index.sai.utils.PrimaryKey; +import org.apache.cassandra.utils.CloseableIterator; + +/** + * A placeholder index for when there is no on-disk index. + * + * Currenly only used by vector indexes becasue ANN queries require a complete view of the table's sstables, even if + * the associated sstable does not have any data indexed for the column. + */ +public class EmptyIndex extends SSTableIndex +{ + public EmptyIndex(SSTableContext sstableContext, StorageAttachedIndex index) + { + super(sstableContext, index); + } + + @Override + public long indexFileCacheSize() + { + return 0; + } + + @Override + public long getRowCount() + { + return 0; + } + + @Override + public long minSSTableRowId() + { + return -1; + } + + @Override + public long maxSSTableRowId() + { + return -1; + } + + @Override + public ByteBuffer minTerm() + { + return null; + } + + @Override + public ByteBuffer maxTerm() + { + return null; Review Comment: Here are the current precedents. When flushing vector indexes from the memtable, we create the `SegmentMetadata` with `ByteBufferUtil.bytes(0)` for the min and max terms. When building via the `SegmentBuilder` with compaction, we don't special case vector and therefore write the actual min or max vector according to the byte comparable representation. When we have an empty index, we don't write the `SegmentMetadata`. I agree we cannot add these `EmptyIndex` objects to the `RangeTermTree`, but I tend to prefer `null` over the exceptional case because we already have some handling showing some assumption that the `minTerm()` and `maxTerm()` methods could return `null`. I don't feel too strongly though. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
