Maxwell-Guo commented on code in PR #2287: URL: https://github.com/apache/cassandra/pull/2287#discussion_r1267570131
########## conf/cassandra.yaml: ########## @@ -1002,6 +1002,19 @@ snapshot_links_per_second: 0 # Min unit: KiB column_index_cache_size: 2KiB +# Default compaction strategy, applied when a table's parameters do not +# specify compaction. +# The default is to use SizeTieredCompactionStrategy, with its default +# threshold of 4 sstables. +# The selected compaction strategy will also apply to system tables. +# +# default_compaction: Review Comment: As this is a newly introduced configuration, so I think we should give a more detailed description abouth the usage, like : class_name should be the different compaction strategy name , parameters sholud be the maps of differen parameters that different compaction strategy used. Then the next is an example ########## conf/cassandra.yaml: ########## @@ -1002,6 +1002,19 @@ snapshot_links_per_second: 0 # Min unit: KiB column_index_cache_size: 2KiB +# Default compaction strategy, applied when a table's parameters do not +# specify compaction. +# The default is to use SizeTieredCompactionStrategy, with its default +# threshold of 4 sstables. Review Comment: The default strategy of STCS here should not only include the lower limit of 4, but also the upper limit of 32, so what about just modify the description to : “The default is to use SizeTieredCompactionStrategy with its defaut compaction params.” It feels more ordinary ########## src/java/org/apache/cassandra/db/compaction/UnifiedCompactionStrategy.md: ########## @@ -0,0 +1,375 @@ +<!-- +# +# Copyright DataStax, Inc. Review Comment: I have missed this before ~~~ line 1 to line 3 I think we should modify these lines. ########## src/java/org/apache/cassandra/db/compaction/unified/ShardedMultiWriter.java: ########## @@ -0,0 +1,254 @@ +/* + * 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.compaction.unified; + +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.db.ColumnFamilyStore; +import org.apache.cassandra.db.DecoratedKey; +import org.apache.cassandra.db.SerializationHeader; +import org.apache.cassandra.db.commitlog.CommitLogPosition; +import org.apache.cassandra.db.commitlog.IntervalSet; +import org.apache.cassandra.db.compaction.ShardTracker; +import org.apache.cassandra.db.lifecycle.LifecycleNewTracker; +import org.apache.cassandra.db.rows.UnfilteredRowIterator; +import org.apache.cassandra.index.Index; +import org.apache.cassandra.io.sstable.Descriptor; +import org.apache.cassandra.io.sstable.SSTableMultiWriter; +import org.apache.cassandra.io.sstable.format.SSTableReader; +import org.apache.cassandra.io.sstable.format.SSTableWriter; +import org.apache.cassandra.io.sstable.metadata.MetadataCollector; +import org.apache.cassandra.schema.TableId; +import org.apache.cassandra.utils.FBUtilities; +import org.apache.cassandra.utils.TimeUUID; + +/** + * A {@link SSTableMultiWriter} that splits the output sstable at the partition boundaries of the compaction + * shards used by {@link org.apache.cassandra.db.compaction.UnifiedCompactionStrategy}. + * <p/> + * This is class is similar to {@link ShardedCompactionWriter} but for flushing. Unfortunately + * we currently have 2 separate writers hierarchy that are not compatible and so we must + * duplicate the functionality. + */ +public class ShardedMultiWriter implements SSTableMultiWriter +{ + protected final static Logger logger = LoggerFactory.getLogger(ShardedMultiWriter.class); + + private final ColumnFamilyStore cfs; + private final Descriptor descriptor; + private final long keyCount; + private final long repairedAt; + private final TimeUUID pendingRepair; + private final boolean isTransient; + private final IntervalSet<CommitLogPosition> commitLogPositions; + private final SerializationHeader header; + private final Collection<Index> indexes; + private final LifecycleNewTracker lifecycleNewTracker; + private final ShardTracker boundaries; + private final SSTableWriter[] writers; + private int currentWriter; + + public ShardedMultiWriter(ColumnFamilyStore cfs, + Descriptor descriptor, + long keyCount, + long repairedAt, + TimeUUID pendingRepair, + boolean isTransient, + IntervalSet<CommitLogPosition> commitLogPositions, + SerializationHeader header, + Collection<Index> indexes, + LifecycleNewTracker lifecycleNewTracker, + ShardTracker boundaries) + { + this.cfs = cfs; + this.descriptor = descriptor; + this.keyCount = keyCount; + this.repairedAt = repairedAt; + this.pendingRepair = pendingRepair; + this.isTransient = isTransient; + this.commitLogPositions = commitLogPositions; + this.header = header; + this.indexes = indexes; + this.lifecycleNewTracker = lifecycleNewTracker; + this.boundaries = boundaries; + this.writers = new SSTableWriter[this.boundaries.count()]; // at least one + + this.currentWriter = 0; + this.writers[currentWriter] = createWriter(descriptor); + } + + private SSTableWriter createWriter() + { + Descriptor newDesc = cfs.newSSTableDescriptor(descriptor.directory); + return createWriter(newDesc); + } + + private SSTableWriter createWriter(Descriptor descriptor) + { + MetadataCollector metadataCollector = new MetadataCollector(cfs.metadata().comparator) + .commitLogIntervals(commitLogPositions != null ? commitLogPositions : IntervalSet.empty()); + return descriptor.getFormat().getWriterFactory().builder(descriptor) + .setKeyCount(forSplittingKeysBy(boundaries.count())) + .setRepairedAt(repairedAt) + .setPendingRepair(pendingRepair) + .setTransientSSTable(isTransient) + .setTableMetadataRef(cfs.metadata) + .setMetadataCollector(metadataCollector) + .setSerializationHeader(header) + .addDefaultComponents() + .addFlushObserversForSecondaryIndexes(indexes, lifecycleNewTracker.opType()) + .build(lifecycleNewTracker, cfs); + } + + private long forSplittingKeysBy(long splits) { + return splits <= 1 ? keyCount : keyCount / splits; + } + + @Override + public void append(UnfilteredRowIterator partition) + { + DecoratedKey key = partition.partitionKey(); + + // If we have written anything and cross a shard boundary, switch to a new writer. + final long currentUncompressedSize = writers[currentWriter].getFilePointer(); + if (boundaries.advanceTo(key.getToken()) && currentUncompressedSize > 0) + { + logger.debug("Switching writer at boundary {}/{} index {}, with uncompressed size {} for {}.{}", + key.getToken(), boundaries.shardStart(), currentWriter, + FBUtilities.prettyPrintMemory(currentUncompressedSize), + cfs.getKeyspaceName(), cfs.getTableName()); + + writers[++currentWriter] = createWriter(); + } + + writers[currentWriter].append(partition); + } + + @Override + public Collection<SSTableReader> finish(boolean openResult) + { + List<SSTableReader> sstables = new ArrayList<>(writers.length); + for (SSTableWriter writer : writers) + if (writer != null) + { + boundaries.applyTokenSpaceCoverage(writer); + sstables.add(writer.finish(openResult)); + } + return sstables; + } + + @Override + public Collection<SSTableReader> finished() + { + List<SSTableReader> sstables = new ArrayList<>(writers.length); + for (SSTableWriter writer : writers) + if (writer != null) + sstables.add(writer.finished()); + return sstables; + } + + @Override + public SSTableMultiWriter setOpenResult(boolean openResult) + { + for (SSTableWriter writer : writers) + if (writer != null) + writer.setOpenResult(openResult); + return this; + } + + @Override + public String getFilename() + { + for (SSTableWriter writer : writers) + if (writer != null) + return writer.getFilename(); + return ""; Review Comment: should file name be "" if all writer is null ? ########## conf/cassandra.yaml: ########## @@ -1002,6 +1002,19 @@ snapshot_links_per_second: 0 # Min unit: KiB column_index_cache_size: 2KiB +# Default compaction strategy, applied when a table's parameters do not +# specify compaction. +# The default is to use SizeTieredCompactionStrategy, with its default +# threshold of 4 sstables. Review Comment: The default strategy of STCS here should not only include the lower limit of 4, but also the upper limit of 32, so what about just modify the description to : “The default is to use SizeTieredCompactionStrategy with its defaut compaction params.” It feels more ordinary -- 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]
