amogh-jahagirdar commented on code in PR #13400: URL: https://github.com/apache/iceberg/pull/13400#discussion_r2395865049
########## core/src/main/java/org/apache/iceberg/RESTTableScan.java: ########## @@ -0,0 +1,312 @@ +/* + * 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; + +import java.util.List; +import java.util.Locale; +import java.util.Map; +import java.util.function.Supplier; +import java.util.stream.Collectors; +import org.apache.iceberg.catalog.TableIdentifier; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.relocated.com.google.common.annotations.VisibleForTesting; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.rest.ErrorHandlers; +import org.apache.iceberg.rest.ParserContext; +import org.apache.iceberg.rest.PlanStatus; +import org.apache.iceberg.rest.RESTClient; +import org.apache.iceberg.rest.ResourcePaths; +import org.apache.iceberg.rest.requests.PlanTableScanRequest; +import org.apache.iceberg.rest.responses.FetchPlanningResultResponse; +import org.apache.iceberg.rest.responses.PlanTableScanResponse; +import org.apache.iceberg.types.Types; +import org.apache.iceberg.util.ParallelIterable; + +public class RESTTableScan extends DataTableScan { + private final RESTClient client; + private final String path; + private final Supplier<Map<String, String>> headers; + private final TableOperations operations; + private final Table table; + private final ResourcePaths resourcePaths; + private final TableIdentifier tableIdentifier; + private final ParserContext parserContext; + + // Track the current plan ID for cancellation + private volatile String currentPlanId = null; + + // TODO revisit if this property should be configurable + // Sleep duration between polling attempts for plan completion + private static final int FETCH_PLANNING_SLEEP_DURATION_MS = 1000; + // Maximum time to wait for scan planning to complete (5 minutes) + // This prevents indefinite blocking on server-side planning issues + private static final long MAX_WAIT_TIME_MS = 5 * 60 * 1000L; + + RESTTableScan( + Table table, + Schema schema, + TableScanContext context, + RESTClient client, + String path, + Supplier<Map<String, String>> headers, + TableOperations operations, + TableIdentifier tableIdentifier, + ResourcePaths resourcePaths) { + super(table, schema, context); + this.table = table; + this.client = client; + this.headers = headers; + this.path = path; + this.operations = operations; + this.tableIdentifier = tableIdentifier; + this.resourcePaths = resourcePaths; + this.parserContext = + ParserContext.builder() + .add("specsById", table.specs()) + .add("caseSensitive", context().caseSensitive()) + .build(); + } + + @Override + protected TableScan newRefinedScan( + Table refinedTable, Schema refinedSchema, TableScanContext refinedContext) { + return new RESTTableScan( + refinedTable, + refinedSchema, + refinedContext, + client, + path, + headers, + operations, + tableIdentifier, + resourcePaths); + } + + @Override + public CloseableIterable<FileScanTask> planFiles() { + Long startSnapshotId = context().fromSnapshotId(); + Long endSnapshotId = context().toSnapshotId(); + Long snapshotId = snapshotId(); + List<String> selectedColumns = + schema().columns().stream().map(Types.NestedField::name).collect(Collectors.toList()); + + List<String> statsFields = null; + if (columnsToKeepStats() != null) { + statsFields = + columnsToKeepStats().stream() + .map(columnId -> schema().findColumnName(columnId)) + .collect(Collectors.toList()); + } + + PlanTableScanRequest.Builder planTableScanRequestBuilder = + new PlanTableScanRequest.Builder() + .withSelect(selectedColumns) + .withFilter(filter()) + .withCaseSensitive(isCaseSensitive()) + .withStatsFields(statsFields); + + if (startSnapshotId != null && endSnapshotId != null) { + planTableScanRequestBuilder + .withStartSnapshotId(startSnapshotId) + .withEndSnapshotId(endSnapshotId) + .withUseSnapshotSchema(true); + + } else if (snapshotId != null) { + boolean useSnapShotSchema = snapshotId != table.currentSnapshot().snapshotId(); + planTableScanRequestBuilder + .withSnapshotId(snapshotId) + .withUseSnapshotSchema(useSnapShotSchema); + + } else { + planTableScanRequestBuilder.withSnapshotId(table().currentSnapshot().snapshotId()); + } + + return planTableScan(planTableScanRequestBuilder.build()); + } + + private CloseableIterable<FileScanTask> planTableScan(PlanTableScanRequest planTableScanRequest) { + + PlanTableScanResponse response = + client.post( + resourcePaths.planTableScan(tableIdentifier), + planTableScanRequest, + PlanTableScanResponse.class, + headers.get(), + ErrorHandlers.defaultErrorHandler(), + stringStringMap -> {}, + parserContext); + + PlanStatus planStatus = response.planStatus(); + switch (planStatus) { + case COMPLETED: + return getScanTasksIterable(response.planTasks(), response.fileScanTasks()); + case SUBMITTED: + return fetchPlanningResult(response.planId()); + case FAILED: + throw new IllegalStateException( + "Received \"failed\" status from service when planning a table scan"); + case CANCELLED: + throw new IllegalStateException( + "Received \"cancelled\" status from service when planning a table scan"); + default: + throw new RuntimeException( + String.format("Invalid planStatus during planTableScan: %s", planStatus)); + } + } + + private CloseableIterable<FileScanTask> fetchPlanningResult(String planId) { + // Set the current plan ID for potential cancellation + currentPlanId = planId; + + try { + long startTime = System.currentTimeMillis(); + while (System.currentTimeMillis() - startTime <= MAX_WAIT_TIME_MS) { + FetchPlanningResultResponse response = + client.get( + resourcePaths.plan(tableIdentifier, planId), + Map.of(), + FetchPlanningResultResponse.class, + headers.get(), + ErrorHandlers.defaultErrorHandler(), + parserContext); + + PlanStatus planStatus = response.planStatus(); + switch (planStatus) { + case COMPLETED: + return getScanTasksIterable(response.planTasks(), response.fileScanTasks()); + case SUBMITTED: + try { + // TODO: if we want to add some jitter here to avoid thundering herd. + Thread.sleep(FETCH_PLANNING_SLEEP_DURATION_MS); + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + // Attempt to cancel the plan before exiting + cancelPlan(); + throw new RuntimeException("Interrupted while fetching plan status", e); + } + break; + case FAILED: + throw new IllegalStateException( + "Received \"failed\" status from service when fetching a table scan"); + case CANCELLED: + throw new IllegalStateException( + String.format( + Locale.ROOT, + "Received \"cancelled\" status from service when fetching a table scan, planId: %s is invalid", + planId)); + default: + throw new IllegalStateException( + String.format( + Locale.ROOT, "Invalid planStatus during fetchPlanningResult: %s", planStatus)); + } + } + // If we reach here, we've exceeded the max wait time + // Attempt to cancel the plan before timing out + cancelPlan(); + throw new IllegalStateException( + String.format( + Locale.ROOT, + "Exceeded max wait time of %d ms when fetching planning result for planId: %s", + MAX_WAIT_TIME_MS, + planId)); + } catch (Exception e) { + // Clear the plan ID on any exception (except successful completion) + // Also attempt to cancel the plan to clean up server resources + try { + cancelPlan(); + } catch (Exception cancelException) { + // Ignore cancellation failures during exception handling + // The original exception is more important + } + throw e; + } + } + + private CloseableIterable<FileScanTask> getScanTasksIterable( + List<String> planTasks, List<FileScanTask> fileScanTasks) { + List<ScanTasksIterable> iterableOfScanTaskIterables = Lists.newArrayList(); + if (fileScanTasks != null) { + // add this to the list for below if planTasks will also be present + ScanTasksIterable scanTasksIterable = + new ScanTasksIterable( + fileScanTasks, + client, + resourcePaths, + tableIdentifier, + headers, + planExecutor(), + table.specs(), + isCaseSensitive(), + this::cancelPlan); + iterableOfScanTaskIterables.add(scanTasksIterable); + } + if (planTasks != null) { + // Use parallel iterable since planTasks are present + for (String planTask : planTasks) { + ScanTasksIterable iterable = + new ScanTasksIterable( + planTask, + client, + resourcePaths, + tableIdentifier, + headers, + planExecutor(), + table.specs(), + isCaseSensitive(), + this::cancelPlan); + iterableOfScanTaskIterables.add(iterable); + } + return new ParallelIterable<>(iterableOfScanTaskIterables, planExecutor()); Review Comment: While I do like the simplicity of the current implementation, I feel like it's a bit over simplistic in that we're wrapping parallel iterables around parallel iterables which I feel is a bit problematic for bounding consumption and memory usage (each level in the pagination will multiply how much memory is allocated across all the queues). In practice I wouldn't expect such crazy depths, but it'd be better if we can make this function just like client side planning where memory is bounded to a single queue; right now it's 30k which at 128mb data files is all the tasks to facilitate ~3.8 TB scan. It would be ideal to also try and eliminate the head-of-line blocking that can happen in the implementation due to a plan task being fetched and blocking on that path, while leaf file scan tasks could still be possible to serve up to a consumer. I don't have a concrete alternative yet, I'm poking around locally but I do think a lot of this is just because of the constraints that a ParallelIterable takes in a defined Iterable of iterables. -- 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. 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