nastra commented on code in PR #5268: URL: https://github.com/apache/iceberg/pull/5268#discussion_r926541887
########## api/src/main/java/org/apache/iceberg/metrics/ScanReport.java: ########## @@ -0,0 +1,251 @@ +/* + * 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.iceberg.metrics; + +import java.io.Serializable; +import java.time.Duration; +import java.util.concurrent.TimeUnit; +import org.apache.iceberg.Schema; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.metrics.MetricsContext.Counter; +import org.apache.iceberg.relocated.com.google.common.base.MoreObjects; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; + +/** + * A Table Scan report that contains all relevant information from a Table Scan. + */ +public class ScanReport implements Serializable { + + private final String tableName; + private final long snapshotId; + private final Expression filter; + private final Schema projection; + private final int matchingDataFiles; + private final int matchingDataManifests; + private final int totalDataManifestsRead; + private final int addedDataFiles; + private final int deletedDataFiles; + private final Duration totalPlanningDuration; + private final long totalFileSizeBytes; + + private ScanReport( + String tableName, long snapshotId, Expression filter, Schema projection, + int matchingDataFiles, int matchingDataManifests, int totalDataManifestsRead, + int addedDataFiles, int deletedDataFiles, Duration totalPlanningDuration, + long totalFileSizeBytes) { + this.tableName = tableName; + this.snapshotId = snapshotId; + this.filter = filter; + this.projection = projection; + this.matchingDataFiles = matchingDataFiles; + this.matchingDataManifests = matchingDataManifests; + this.totalDataManifestsRead = totalDataManifestsRead; + this.addedDataFiles = addedDataFiles; + this.deletedDataFiles = deletedDataFiles; + this.totalPlanningDuration = totalPlanningDuration; + this.totalFileSizeBytes = totalFileSizeBytes; + } + + public String tableName() { + return tableName; + } + + public long snapshotId() { + return snapshotId; + } + + public Expression filter() { + return filter; + } + + public Schema projection() { + return projection; + } + + public int matchingDataFiles() { + return matchingDataFiles; + } + + public int matchingDataManifests() { + return matchingDataManifests; + } + + public int totalDataManifestsRead() { + return totalDataManifestsRead; + } + + public int addedDataFiles() { + return addedDataFiles; + } + + public int deletedDataFiles() { + return deletedDataFiles; + } + + public Duration totalPlanningDuration() { + return totalPlanningDuration; + } + + public long totalFileSizeBytes() { + return totalFileSizeBytes; + } + + public static Builder builder() { + return new Builder(); + } + + @Override + public String toString() { + return MoreObjects.toStringHelper(this) + .add("tableName", tableName) + .add("snapshotId", snapshotId) + .add("filter", filter) + .add("projection", projection) + .add("matchingDataFiles", matchingDataFiles) + .add("matchingDataManifests", matchingDataManifests) + .add("totalDataManifestsRead", totalDataManifestsRead) + .add("addedDataFiles", addedDataFiles) + .add("deletedDataFiles", deletedDataFiles) + .add("totalScanDuration", totalPlanningDuration) + .add("totalFileSizeBytes", totalFileSizeBytes) + .toString(); + } + + @SuppressWarnings("HiddenField") + public static class Builder { + private String tableName; + private long snapshotId = -1L; + private Expression filter; + private Schema projection; + private ScanMetrics scanMetrics; + + private Builder() { + } + + public Builder withTableName(String tableName) { + this.tableName = tableName; + return this; + } + + public Builder withSnapshotId(long snapshotId) { + this.snapshotId = snapshotId; + return this; + } + + public Builder withFilter(Expression filter) { + this.filter = filter; + return this; + } + + public Builder withProjection(Schema projection) { + this.projection = projection; + return this; + } + + public Builder fromScanMetrics(ScanMetrics scanMetrics) { + this.scanMetrics = scanMetrics; + return this; + } + + public ScanReport build() { + Preconditions.checkArgument(null != tableName, "TableName must be non-null"); + Preconditions.checkArgument(null != filter, "Expression filter must be non-null"); + Preconditions.checkArgument(null != projection, "Schema projection must be non-null"); + Preconditions.checkArgument(null != scanMetrics, "ScanMetrics must be non-null"); + return new ScanReport(tableName, snapshotId, filter, projection, + scanMetrics.matchingDataFiles().count().orElse(-1), Review Comment: one of the reasons I added this distinction between `ScanMetrics` and the final `ScanReport` is so that we wouldn't need to serialize Counters/Timers. Additionally, it seemed cleaner to me to have metrics that are being updated wrapped in one class, where we would derive a final `ScanReport` from that is immutable (well kind-of). The `ScanReport` is just a Data holder that is serializable, but it doesn't carry the baggage of whatever a particular `Counter`/`Timer` implementation would have. I understand the reasoning behind making `Counter#count()` return an `Optional` but I was actually wondering whether it wouldn't be better to make this return an actual value. It seems overly restrictive to have this be an `Optional` for a special case, such as Hadoop. Also you generally don't see such a restriction in the Counter API of Micrometer. Maybe in such a case the `Counters` that are being produced by `HadoopMetricsContext` would just return -1 for `count()` if they can't fetch whatever they are counting from `FileSystem.Statistics`. @danielcweeks thoughts on this? -- This is an automated message from the Apache Git Service. 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