michaelsembwever commented on code in PR #236: URL: https://github.com/apache/cassandra-analytics/pull/236#discussion_r3992715325
########## cassandra-six-zero-bridge/src/main/java/org/apache/cassandra/spark/reader/SSTableReader.java: ########## @@ -0,0 +1,987 @@ +/* + * 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.spark.reader; + +import java.io.DataInputStream; +import java.io.EOFException; +import java.io.IOError; +import java.io.IOException; +import java.math.BigInteger; +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.Optional; +import java.util.Set; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.atomic.AtomicReference; +import java.util.function.Function; +import java.util.function.Supplier; +import java.util.stream.Collectors; + +import com.google.common.base.Preconditions; +import com.google.common.base.Suppliers; +import com.google.common.collect.ImmutableList; +import com.google.common.collect.Streams; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.bridge.TokenRange; +import org.apache.cassandra.config.DatabaseDescriptor; +import org.apache.cassandra.cql3.ColumnIdentifier; +import org.apache.cassandra.db.DecoratedKey; +import org.apache.cassandra.db.DeletionTime; +import org.apache.cassandra.db.RegularAndStaticColumns; +import org.apache.cassandra.db.SerializationHeader; +import org.apache.cassandra.db.UnfilteredDeserializer; +import org.apache.cassandra.db.compression.CompressionDictionary; +import org.apache.cassandra.db.filter.ColumnFilter; +import org.apache.cassandra.db.marshal.AbstractType; +import org.apache.cassandra.db.marshal.UTF8Type; +import org.apache.cassandra.db.rows.DeserializationHelper; +import org.apache.cassandra.db.rows.EncodingStats; +import org.apache.cassandra.db.rows.Row; +import org.apache.cassandra.db.rows.Unfiltered; +import org.apache.cassandra.db.rows.UnfilteredRowIterator; +import org.apache.cassandra.io.sstable.Descriptor; +import org.apache.cassandra.io.sstable.ISSTableScanner; +import org.apache.cassandra.io.sstable.SSTableSimpleIterator; +import org.apache.cassandra.io.sstable.format.SSTableFormat; +import org.apache.cassandra.io.sstable.format.Version; +import org.apache.cassandra.io.sstable.format.bti.BtiReaderUtils; +import org.apache.cassandra.io.sstable.indexsummary.IndexSummary; +import org.apache.cassandra.io.sstable.metadata.MetadataComponent; +import org.apache.cassandra.io.sstable.metadata.MetadataType; +import org.apache.cassandra.io.sstable.metadata.StatsMetadata; +import org.apache.cassandra.io.sstable.metadata.ValidationMetadata; +import org.apache.cassandra.io.util.DataInputPlus; +import org.apache.cassandra.io.util.DataInputStreamPlus; +import org.apache.cassandra.schema.ColumnMetadata; +import org.apache.cassandra.schema.DroppedColumn; +import org.apache.cassandra.schema.TableMetadata; +import org.apache.cassandra.service.ActiveRepairService; +import org.apache.cassandra.spark.data.SSTable; +import org.apache.cassandra.analytics.reader.common.RawInputStream; +import org.apache.cassandra.spark.reader.common.SSTableStreamException; +import org.apache.cassandra.spark.sparksql.filters.PartitionKeyFilter; +import org.apache.cassandra.spark.sparksql.filters.PruneColumnFilter; +import org.apache.cassandra.spark.sparksql.filters.SparkRangeFilter; +import org.apache.cassandra.analytics.stats.Stats; +import org.apache.cassandra.spark.sparksql.filters.SSTableTimeRangeFilter; +import org.apache.cassandra.spark.utils.ByteBufferUtils; +import org.apache.cassandra.spark.utils.Pair; +import org.apache.cassandra.spark.utils.ThrowableUtils; +import org.apache.cassandra.utils.ByteBufferUtil; +import org.apache.cassandra.utils.concurrent.Ref; +import org.jetbrains.annotations.NotNull; +import org.jetbrains.annotations.Nullable; + +@SuppressWarnings("unused") +public class SSTableReader implements SparkSSTableReader, Scannable +{ + private static final Logger LOGGER = LoggerFactory.getLogger(SSTableReader.class); + + private final TableMetadata metadata; + @NotNull + private final SSTable ssTable; + private final StatsMetadata statsMetadata; + @NotNull + private final Version version; + @NotNull + private final DecoratedKey first; + @NotNull + private final DecoratedKey last; + @NotNull + private final BigInteger firstToken; + @NotNull + private final BigInteger lastToken; + private final SerializationHeader header; + private final DeserializationHelper helper; + @NotNull + private final AtomicReference<SSTableStreamReader> reader = new AtomicReference<>(null); + @Nullable + private final SparkRangeFilter sparkRangeFilter; + @NotNull + private final List<PartitionKeyFilter> partitionKeyFilters; + @NotNull + private final SSTableTimeRangeFilter sstableTimeRangeFilter; + @NotNull + private final Stats stats; + @Nullable + private Long startOffset = null; + private Long openedNanos = null; + @NotNull + private final Function<StatsMetadata, Boolean> isRepaired; + + public static class Builder + { + @NotNull + final TableMetadata metadata; + @NotNull + final SSTable ssTable; + @Nullable + PruneColumnFilter columnFilter = null; + boolean readIndexOffset = true; + @NotNull + Stats stats = Stats.DoNothingStats.INSTANCE; + boolean useIncrementalRepair = true; + boolean isRepairPrimary = false; + Function<StatsMetadata, Boolean> isRepaired = stats -> stats.repairedAt != ActiveRepairService.UNREPAIRED_SSTABLE; + @Nullable + SparkRangeFilter sparkRangeFilter = null; + @NotNull + final List<PartitionKeyFilter> partitionKeyFilters = new ArrayList<>(); + @NotNull + SSTableTimeRangeFilter sstableTimeRangeFilter = SSTableTimeRangeFilter.ALL; + + Builder(@NotNull TableMetadata metadata, @NotNull SSTable ssTable) + { + this.metadata = metadata; + this.ssTable = ssTable; + } + + public Builder withSparkRangeFilter(@Nullable SparkRangeFilter sparkRangeFilter) + { + this.sparkRangeFilter = sparkRangeFilter; + return this; + } + + public Builder withPartitionKeyFilters(@Nullable Collection<PartitionKeyFilter> partitionKeyFilters) + { + if (partitionKeyFilters != null) + { + this.partitionKeyFilters.addAll(partitionKeyFilters); + } + return this; + } + + public Builder withPartitionKeyFilter(@NotNull PartitionKeyFilter partitionKeyFilter) + { + partitionKeyFilters.add(partitionKeyFilter); + return this; + } + + public Builder withTimeRangeFilter(@Nullable SSTableTimeRangeFilter sstableTimeRangeFilter) + { + if (sstableTimeRangeFilter != null) + { + this.sstableTimeRangeFilter = sstableTimeRangeFilter; + } + return this; + } + + public Builder withColumnFilter(@Nullable PruneColumnFilter columnFilter) + { + this.columnFilter = columnFilter; + return this; + } + + public Builder withReadIndexOffset(boolean readIndexOffset) + { + this.readIndexOffset = readIndexOffset; + return this; + } + + public Builder withStats(@NotNull Stats stats) + { + this.stats = stats; + return this; + } + + public Builder useIncrementalRepair(boolean useIncrementalRepair) + { + this.useIncrementalRepair = useIncrementalRepair; + return this; + } + + public Builder isRepairPrimary(boolean isRepairPrimary) + { + this.isRepairPrimary = isRepairPrimary; + return this; + } + + public Builder withIsRepairedFunction(Function<StatsMetadata, Boolean> isRepaired) + { + this.isRepaired = isRepaired; + return this; + } + + public SSTableReader build() throws IOException + { + return new SSTableReader(metadata, + ssTable, + sparkRangeFilter, + partitionKeyFilters, + sstableTimeRangeFilter, + columnFilter, + readIndexOffset, + stats, + useIncrementalRepair, + isRepairPrimary, + isRepaired); + } + } + + public static Builder builder(@NotNull TableMetadata metadata, @NotNull SSTable ssTable) + { + return new Builder(metadata, ssTable); + } + + // CHECKSTYLE IGNORE: Constructor with many parameters + public SSTableReader(@NotNull TableMetadata metadata, + @NotNull SSTable ssTable, + @Nullable SparkRangeFilter sparkRangeFilter, + @NotNull List<PartitionKeyFilter> partitionKeyFilters, + @NotNull SSTableTimeRangeFilter sstableTimeRangeFilter, + @Nullable PruneColumnFilter columnFilter, + boolean readIndexOffset, + @NotNull Stats stats, + boolean useIncrementalRepair, + boolean isRepairPrimary, + @NotNull Function<StatsMetadata, Boolean> isRepaired) throws IOException + { + long startTimeNanos = System.nanoTime(); + long now; + this.ssTable = ssTable; + this.stats = stats; + this.isRepaired = isRepaired; + this.sparkRangeFilter = sparkRangeFilter; + + Descriptor descriptor = ReaderUtils.constructDescriptor(metadata.keyspace, metadata.name, ssTable); + this.version = descriptor.version; + + SummaryDbUtils.Summary summary = null; + Pair<DecoratedKey, DecoratedKey> keys = null; + try + { + now = System.nanoTime(); + if (ssTable.isBigFormat()) + { + summary = SSTableCache.INSTANCE.keysFromSummary(metadata, ssTable); + stats.readSummaryDb(ssTable, System.nanoTime() - now); + keys = Pair.of(summary.first(), summary.last()); + } + } + catch (IOException exception) + { + LOGGER.warn("Failed to read Summary.db file ssTable='{}'", ssTable, exception); + } + + if (keys == null) + { + if (ssTable.isBigFormat()) + { + LOGGER.warn("Could not load first and last key from Summary.db file, so attempting Index.db fileName={}", + ssTable.getDataFileName()); + } + now = System.nanoTime(); + keys = SSTableCache.INSTANCE.keysFromIndex(metadata, ssTable); + stats.readIndexDb(ssTable, System.nanoTime() - now); + } + + if (keys == null) + { + throw new IOException("Could not load SSTable first or last tokens"); + } + + this.first = keys.left; + this.last = keys.right; + this.firstToken = ReaderUtils.tokenToBigInteger(first.getToken()); + this.lastToken = ReaderUtils.tokenToBigInteger(last.getToken()); + TokenRange readerRange = range(); + + List<PartitionKeyFilter> matchingKeyFilters = partitionKeyFilters.stream() + .filter(filter -> readerRange.contains(filter.token())) + .collect(Collectors.toList()); + boolean overlapsSparkRange = sparkRangeFilter == null || SparkSSTableReader.overlaps(this, sparkRangeFilter.tokenRange()); + if (!overlapsSparkRange // SSTable doesn't overlap with Spark worker token range + || (matchingKeyFilters.isEmpty() && !partitionKeyFilters.isEmpty())) // No matching partition key filters overlap with SSTable + { + this.partitionKeyFilters = Collections.emptyList(); + stats.skippedSSTable(sparkRangeFilter, partitionKeyFilters, firstToken, lastToken); + LOGGER.info("Ignoring SSTableReader with firstToken={} lastToken={}, does not overlap with any filter", + firstToken, lastToken); + statsMetadata = null; + header = null; + helper = null; + this.metadata = null; + this.sstableTimeRangeFilter = SSTableTimeRangeFilter.ALL; + return; + } + + if (!matchingKeyFilters.isEmpty()) + { + List<PartitionKeyFilter> matchInBloomFilter = + ReaderUtils.filterKeyInBloomFilter(ssTable, metadata.partitioner, descriptor, matchingKeyFilters); + this.partitionKeyFilters = ImmutableList.copyOf(matchInBloomFilter); + + // Check if required keys are actually present + if (matchInBloomFilter.isEmpty() || !ReaderUtils.anyFilterKeyInIndex(ssTable, metadata, descriptor, matchInBloomFilter)) + { + if (matchInBloomFilter.isEmpty()) + { + stats.missingInBloomFilter(); + } + else + { + stats.missingInIndex(); + } + LOGGER.info("Ignoring SSTable {}, no match found in index file for key filters", + this.ssTable.getDataFileName()); + statsMetadata = null; + header = null; + helper = null; + this.metadata = null; + this.sstableTimeRangeFilter = SSTableTimeRangeFilter.ALL; + return; + } + } + else + { + this.partitionKeyFilters = ImmutableList.copyOf(partitionKeyFilters); + } + + Map<MetadataType, MetadataComponent> componentMap = SSTableCache.INSTANCE.componentMapFromStats(ssTable, descriptor); + + ValidationMetadata validation = (ValidationMetadata) componentMap.get(MetadataType.VALIDATION); + if (validation != null && !validation.partitioner.equals(metadata.partitioner.getClass().getName())) + { + throw new IllegalStateException("Partitioner in ValidationMetadata does not match TableMetaData: " + + validation.partitioner + " vs. " + metadata.partitioner.getClass().getName()); + } + + this.statsMetadata = (StatsMetadata) componentMap.get(MetadataType.STATS); + if (!sstableTimeRangeFilter.overlaps(statsMetadata.minTimestamp, statsMetadata.maxTimestamp)) + { + LOGGER.info("Ignoring SSTableReader with minTimestamp={} maxTimestamp={}, does not overlap with filter {}", + this.statsMetadata.minTimestamp, this.statsMetadata.maxTimestamp, sstableTimeRangeFilter); + header = null; + helper = null; + this.metadata = null; + this.sstableTimeRangeFilter = SSTableTimeRangeFilter.ALL; + return; + } + else + { + this.sstableTimeRangeFilter = sstableTimeRangeFilter; + } + + SerializationHeader.Component headerComp = (SerializationHeader.Component) componentMap.get(MetadataType.HEADER); + if (headerComp == null) + { + throw new IOException("Cannot read SSTable if cannot deserialize stats header info"); + } + + if (useIncrementalRepair && !isRepairPrimary && isRepaired()) + { + stats.skippedRepairedSSTable(ssTable, statsMetadata.repairedAt); + LOGGER.info("Ignoring repaired SSTable on non-primary repair replica ssTable='{}' repairedAt={}", + ssTable, statsMetadata.repairedAt); + header = null; + helper = null; + this.metadata = null; + return; + } + + Set<String> columnNames = Streams.concat(metadata.columns().stream(), + metadata.staticColumns().stream()) + .map(column -> column.name.toString()) + .collect(Collectors.toSet()); + // Cassandra 6.0 gives every column a uniqueId, and TableMetadata.Builder assigns one only when no column + // already has one, so a dropped column added here must carry an explicit id. Seed the map with the + // table's own dropped columns, so that the ids they hold stay accounted for. + Map<ByteBuffer, DroppedColumn> droppedColumns = new HashMap<>(metadata.droppedColumns); + int knownDroppedColumns = droppedColumns.size(); + // Almost every SSTable adds no dropped column, so pay for the id scan only when one does + TableMetadata schemaMetadata = metadata; + Supplier<AtomicInteger> nextUniqueId = Suppliers.memoize(() -> new AtomicInteger(nextUniqueId(schemaMetadata))); + addDroppedColumns(droppedColumns, + nextUniqueId, + metadata.keyspace, + metadata.name, + ssTable, + headerComp.getRegularColumns(), + columnNames, + ColumnMetadata.Kind.REGULAR); + addDroppedColumns(droppedColumns, + nextUniqueId, + metadata.keyspace, + metadata.name, + ssTable, + headerComp.getStaticColumns(), + columnNames, + ColumnMetadata.Kind.STATIC); + if (droppedColumns.size() > knownDroppedColumns) + { + LOGGER.info("Rebuilding table metadata with dropped columns numDroppedColumns={} ssTable='{}'", + droppedColumns.size(), ssTable); + metadata = metadata.unbuild().droppedColumns(droppedColumns).build(); + } + + this.header = headerComp.toHeader(metadata); + this.helper = new DeserializationHelper(metadata, + getSSTableVersion(ssTable).correspondingMessagingVersion(), + DeserializationHelper.Flag.FROM_REMOTE, + buildColumnFilter(metadata, columnFilter)); + this.metadata = metadata; + + if (readIndexOffset) + { + if (summary != null) + { + // BIG format + SummaryDbUtils.Summary finalSummary = summary; + extractRange(sparkRangeFilter, partitionKeyFilters) + .ifPresent(range -> readOffsets(finalSummary.summary(), range)); + } + else + { + // BTI format + extractRange(sparkRangeFilter, partitionKeyFilters) + .ifPresent(range -> { + startOffset = BtiReaderUtils.startOffsetInDataFile(ssTable, + this.metadata, + descriptor, + range); + }); + } + } + else + { + LOGGER.warn("Reading SSTable without looking up start/end offset, performance will potentially be degraded"); + } + + // Open SSTableStreamReader so opened in parallel inside thread pool + // and buffered + ready to go when CompactionIterator starts reading + reader.set(new SSTableStreamReader()); + stats.openedSSTable(ssTable, System.nanoTime() - startTimeNanos); + this.openedNanos = System.nanoTime(); + } + + /** + * Return the first column uniqueId that no column of the table uses, continuing the single sequence that + * Cassandra 6.0 numbers the live and the dropped columns in + */ + private static int nextUniqueId(TableMetadata metadata) + { + int highest = ColumnMetadata.NO_UNIQUE_ID; + // columns() covers the partition key, clustering, regular and static columns + for (ColumnMetadata column : metadata.columns()) + { + highest = Math.max(highest, column.uniqueId); + } + for (DroppedColumn dropped : metadata.droppedColumns.values()) + { + highest = Math.max(highest, dropped.column.uniqueId); + } + int nextId = Math.max(0, highest + 1); + // TableMetadata sizes its by-id column array at one slot per addressable column and indexes it by + // uniqueId, so the ids must run 0..size-1 for each id assigned from here to land inside the array + int addressableColumns = metadata.regularAndStaticAndDroppedColumns().size() + + metadata.partitionKeyColumns().size() + + metadata.clusteringColumns().size(); + Preconditions.checkState(nextId <= addressableColumns, + "Column uniqueIds of %s.%s exceed the by-id array: nextId=%s columns=%s", + metadata.keyspace, metadata.name, nextId, addressableColumns); + return nextId; + } + + /** + * Add one dropped column for every column of the SSTable that the table schema does not hold, taking each + * uniqueId from {@code nextUniqueId} + */ + private static void addDroppedColumns(Map<ByteBuffer, DroppedColumn> droppedColumns, + Supplier<AtomicInteger> nextUniqueId, + String keyspace, + String table, + SSTable ssTable, + Map<ByteBuffer, AbstractType<?>> columns, + Set<String> columnNames, + ColumnMetadata.Kind kind) + { + for (Map.Entry<ByteBuffer, AbstractType<?>> entry : columns.entrySet()) + { + String colName = UTF8Type.instance.getString((entry.getKey())); + if (!columnNames.contains(colName) && !droppedColumns.containsKey(entry.getKey())) + { + AbstractType<?> type = entry.getValue(); + LOGGER.warn("Dropped column found colName={} sstable='{}'", colName, ssTable); + ColumnMetadata column = new ColumnMetadata(keyspace, + table, + ColumnIdentifier.getInterned(colName, true), + type, + nextUniqueId.get().getAndIncrement(), + ColumnMetadata.NO_POSITION, + kind, + null); // TODO: Honor server-side column masking. + long droppedTime = TimeUnit.MILLISECONDS.toMicros(System.currentTimeMillis()) + - TimeUnit.MINUTES.toMicros(60); + droppedColumns.put(entry.getKey(), new DroppedColumn(column, droppedTime)); + } + } + } + + /** + * Merge all the partition key filters to give the token range we care about. + * If no partition key filters, then use the Spark worker token range. + * + * @param sparkRangeFilter optional spark range filter + * @param partitionKeyFilters list of partition key filters + * @return the token range we care about for this Spark worker + */ + public static Optional<TokenRange> extractRange(@Nullable SparkRangeFilter sparkRangeFilter, + @NotNull List<PartitionKeyFilter> partitionKeyFilters) + { + Optional<TokenRange> partitionKeyRange = partitionKeyFilters.stream() + .map(PartitionKeyFilter::tokenRange) + .reduce(TokenRange::merge); + return partitionKeyRange.isPresent() + ? partitionKeyRange + : Optional.ofNullable(sparkRangeFilter != null ? sparkRangeFilter.tokenRange() : null); + } + + /** + * Read Data.db offsets by binary searching Summary.db into Index.db, then reading offsets in Index.db + * + * @param indexSummary Summary.db index summary + * @param range token range we care about for this Spark worker + */ + private void readOffsets(IndexSummary indexSummary, TokenRange range) + { + try + { + // If start is null we failed to find an overlapping token in the Index.db file, + // this is unlikely as we already pre-filter the SSTable based on the start-end token range. + // But in this situation we read the entire Data.db file to be safe, even if it hits performance. + startOffset = IndexDbUtils.findDataDbOffset(indexSummary, range, metadata.partitioner, ssTable, stats); + if (startOffset == null) + { + LOGGER.error("Failed to find Data.db start offset, performance will be degraded sstable='{}'", ssTable); + } + } + catch (IOException exception) + { + LOGGER.warn("IOException finding SSTable offsets, cannot skip directly to start offset in Data.db. " + + "Performance will be degraded.", exception); + } + } + + /** + * Build a ColumnFilter if we need to prune any columns for more efficient deserialization of the SSTable + * + * @param metadata TableMetadata object + * @param columnFilter prune column filter + * @return ColumnFilter if and only if we can prune any columns when deserializing the SSTable, + * otherwise return null + */ + @Nullable + private static ColumnFilter buildColumnFilter(TableMetadata metadata, @Nullable PruneColumnFilter columnFilter) + { + if (columnFilter == null) + { + return null; + } + List<ColumnMetadata> include = metadata.columns().stream() + .filter(column -> columnFilter.includeColumn(column.name.toString())) + .collect(Collectors.toList()); + if (include.size() == metadata.columns().size()) + { + return null; // No columns pruned + } + return ColumnFilter.allRegularColumnsBuilder(metadata, false) + .addAll(include) + .build(); + } + + public SSTable sstable() + { + return ssTable; + } + + public boolean ignore() + { + return reader.get() == null; + } + + @Override + public int hashCode() + { + return Objects.hash(metadata.keyspace, metadata.name, ssTable); + } + + @Override + public boolean equals(Object other) + { + return other instanceof SSTableReader + && this.metadata.keyspace.equals(((SSTableReader) other).metadata.keyspace) + && this.metadata.name.equals(((SSTableReader) other).metadata.name) + && this.ssTable.equals(((SSTableReader) other).ssTable); + } + + public boolean isRepaired() + { + return isRepaired.apply(statsMetadata); + } + + public DecoratedKey first() + { + return first; + } + + public DecoratedKey last() + { + return last; + } + + public long getMinTimestamp() + { + return statsMetadata.minTimestamp; + } + + public long getMaxTimestamp() + { + return statsMetadata.maxTimestamp; + } + + public StatsMetadata getSSTableMetadata() + { + return statsMetadata; + } + + @Override + public ISSTableScanner scanner() + { + ISSTableScanner result = reader.getAndSet(null); + if (result == null) + { + throw new IllegalStateException("SSTableStreamReader cannot be re-used"); + } + return result; + } + + @Override + @NotNull + public BigInteger firstToken() + { + return firstToken; + } + + @Override + @NotNull + public BigInteger lastToken() + { + return lastToken; + } + + public class SSTableStreamReader implements ISSTableScanner + { + private final DataInputStream dis; + private final DataInputPlus in; + final RawInputStream dataStream; + private DecoratedKey key; + private DeletionTime partitionLevelDeletion; + private SSTableSimpleIterator iterator; + private Row staticRow; + @Nullable + private final BigInteger lastToken; + // Cassandra 6.0 decompresses through native zstd tables that a compression dictionary owns. Hold a + // reference for the life of this scanner, so a removal from SSTableCache cannot free them mid-read + @Nullable + private final Ref<? extends CompressionDictionary> dictionaryRef; + private long lastTimeNanos = System.nanoTime(); + + SSTableStreamReader() throws IOException + { + lastToken = sparkRangeFilter != null ? sparkRangeFilter.tokenRange().upperEndpoint() : null; + @Nullable CompressionMetadata compressionMetadata = SSTableCache.INSTANCE.compressionMetadata(ssTable, + version.hasMaxCompressedLength(), + metadata.params.crcCheckChance); + dictionaryRef = compressionMetadata != null ? compressionMetadata.acquireDictionaryRef() : null; Review Comment: The dictionary itself is used twice before the constructor returns: CompressedRawInputStream.from(...) allocates through CompressionMetadata.compressor(), and skipFully(...) decompresses every chunk it skips. see https://github.com/apache/cassandra-analytics/pull/236/changes/16d6c8fceb6fb3e535a66857e2a10f12175da2c9 -- This is an automated message from the Apache Git Service. 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