| /* |
| * 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.db.memtable; |
| |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.cassandra.db.commitlog.CommitLogPosition; |
| import org.apache.cassandra.schema.TableMetadataRef; |
| import org.apache.cassandra.utils.FBUtilities; |
| import org.apache.cassandra.utils.MBeanWrapper; |
| import org.github.jamm.Unmetered; |
| |
| import static org.apache.cassandra.config.CassandraRelevantProperties.MEMTABLE_SHARD_COUNT; |
| |
| public abstract class AbstractShardedMemtable extends AbstractAllocatorMemtable |
| { |
| private static final Logger logger = LoggerFactory.getLogger(AbstractShardedMemtable.class); |
| |
| public static final String SHARDS_OPTION = "shards"; |
| public static final String SHARDED_MEMTABLE_CONFIG_OBJECT_NAME = "org.apache.cassandra.db:type=ShardedMemtableConfig"; |
| static |
| { |
| MBeanWrapper.instance.registerMBean(new ShardedMemtableConfig(), SHARDED_MEMTABLE_CONFIG_OBJECT_NAME, MBeanWrapper.OnException.LOG); |
| } |
| |
| // default shard count, used when a specific number of shards is not specified in the options |
| private static volatile int defaultShardCount = MEMTABLE_SHARD_COUNT.getInt(FBUtilities.getAvailableProcessors()); |
| |
| // The boundaries for the keyspace as they were calculated when the memtable is created. |
| // The boundaries will be NONE for system keyspaces or if StorageService is not yet initialized. |
| // The fact this is fixed for the duration of the memtable lifetime, guarantees we'll always pick the same shard |
| // for a given key, even if we race with the StorageService initialization or with topology changes. |
| @Unmetered |
| protected final ShardBoundaries boundaries; |
| |
| AbstractShardedMemtable(AtomicReference<CommitLogPosition> commitLogLowerBound, |
| TableMetadataRef metadataRef, |
| Owner owner, |
| Integer shardCountOption) |
| { |
| super(commitLogLowerBound, metadataRef, owner); |
| int shardCount = shardCountOption != null ? shardCountOption : defaultShardCount; |
| this.boundaries = owner.localRangeSplits(shardCount); |
| } |
| |
| private static class ShardedMemtableConfig implements ShardedMemtableConfigMXBean |
| { |
| @Override |
| public void setDefaultShardCount(String shardCount) |
| { |
| if ("auto".equalsIgnoreCase(shardCount)) |
| { |
| defaultShardCount = FBUtilities.getAvailableProcessors(); |
| } |
| else |
| { |
| try |
| { |
| defaultShardCount = Integer.parseInt(shardCount); |
| } |
| catch (NumberFormatException ex) |
| { |
| logger.warn("Unable to parse {} as valid value for shard count", shardCount); |
| return; |
| } |
| } |
| logger.info("Requested setting shard count to {}; set to: {}", shardCount, defaultShardCount); |
| } |
| |
| @Override |
| public String getDefaultShardCount() |
| { |
| return Integer.toString(defaultShardCount); |
| } |
| } |
| |
| public static int getDefaultShardCount() |
| { |
| return defaultShardCount; |
| } |
| } |