| /* |
| * 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.transactions; |
| |
| import org.apache.cassandra.db.DeletionTime; |
| import org.apache.cassandra.db.RangeTombstone; |
| import org.apache.cassandra.db.rows.Row; |
| |
| /** |
| * Handling of index updates on the write path. |
| * |
| * Instances of an UpdateTransaction are scoped to a single partition update |
| * A new instance is used for every write, obtained from the |
| * newUpdateTransaction(PartitionUpdate) method. Likewise, a single |
| * CleanupTransaction instance is used for each partition processed during a |
| * compaction or cleanup. |
| * |
| * We make certain guarantees about the lifecycle of each UpdateTransaction |
| * instance. Namely that start() will be called before any other method, and |
| * commit() will be called at the end of the update. |
| * Each instance is initialized with 1..many Index.Indexer instances, one per |
| * registered Index. As with the transaction itself, these are scoped to a |
| * specific partition update, so implementations can be assured that all indexing |
| * events they receive relate to the same logical operation. |
| * |
| * onPartitionDelete(), onRangeTombstone(), onInserted() and onUpdated() |
| * calls may arrive in any order, but this should have no impact for the |
| * Indexers being notified as any events delivered to a single instance |
| * necessarily relate to a single partition. |
| * |
| * The typical sequence of events during a Memtable update would be: |
| * start() -- no-op, used to notify Indexers of the start of the transaction |
| * onPartitionDeletion(dt) -- if the PartitionUpdate implies one |
| * onRangeTombstone(rt)* -- for each in the PartitionUpdate, if any |
| * |
| * then: |
| * onInserted(row)* -- called for each Row not already present in the Memtable |
| * onUpdated(existing, updated)* -- called for any Row in the update for where a version was already present |
| * in the Memtable. It's important to note here that existing is the previous |
| * row from the Memtable & updated is the final version replacing it. It is |
| * *not* the incoming row, but the result of merging the incoming and existing |
| * rows. |
| * commit() -- finally, finish is called when the new Partition is swapped into the Memtable |
| */ |
| public interface UpdateTransaction extends IndexTransaction |
| { |
| void onPartitionDeletion(DeletionTime deletionTime); |
| void onRangeTombstone(RangeTombstone rangeTombstone); |
| void onInserted(Row row); |
| void onUpdated(Row existing, Row updated); |
| |
| UpdateTransaction NO_OP = new UpdateTransaction() |
| { |
| public void start(){} |
| public void onPartitionDeletion(DeletionTime deletionTime){} |
| public void onRangeTombstone(RangeTombstone rangeTombstone){} |
| public void onInserted(Row row){} |
| public void onUpdated(Row existing, Row updated){} |
| public void commit(){} |
| }; |
| } |