osscm commented on code in PR #9830: URL: https://github.com/apache/iceberg/pull/9830#discussion_r3525678324
########## spark/v3.5/spark-extensions/src/main/scala/org/apache/spark/sql/execution/datasources/v2/RefreshMaterializedViewExec.scala: ########## @@ -0,0 +1,148 @@ +/* + * 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.spark.sql.execution.datasources.v2 + +import org.apache.iceberg.catalog.Namespace +import org.apache.iceberg.catalog.TableIdentifier +import org.apache.iceberg.relocated.com.google.common.base.Preconditions +import org.apache.iceberg.spark.SparkCatalog +import org.apache.iceberg.view.RefreshState +import org.apache.iceberg.view.RefreshStateParser +import org.apache.iceberg.view.SourceTableState +import org.apache.iceberg.view.SQLViewRepresentation +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.analysis.NoSuchTableException +import org.apache.spark.sql.catalyst.expressions.Attribute +import org.apache.spark.sql.connector.catalog.Identifier +import org.apache.spark.sql.connector.catalog.ViewCatalog +import org.apache.spark.sql.functions +import scala.collection.JavaConverters._ + +case class RefreshMaterializedViewExec(catalog: ViewCatalog, ident: Identifier) + extends LeafV2CommandExec { + + override def output: Seq[Attribute] = Nil + + override protected def run(): Seq[InternalRow] = { + val sparkCatalog = catalog.asInstanceOf[SparkCatalog] + val icebergCatalog = sparkCatalog.icebergCatalog() + val icebergViewCatalog = + icebergCatalog.asInstanceOf[org.apache.iceberg.catalog.ViewCatalog] + val viewId = TableIdentifier.of(Namespace.of(ident.namespace(): _*), ident.name()) + val view = icebergViewCatalog.loadView(viewId) + + val storageTableId = view.currentVersion().storageTable() + Preconditions.checkState( + storageTableId != null, + "Cannot refresh %s: not a materialized view (no storage table)", + ident) + + // Extract the SQL query from the view's representations + val sparkSql = view + .currentVersion() + .representations() + .asScala + .collect { case sql: SQLViewRepresentation if sql.dialect() == "spark" => sql.sql() } + .headOption + .getOrElse(throw new IllegalStateException( + s"Cannot refresh $ident: no Spark SQL representation found")) + + val refreshStartTimestampMs = System.currentTimeMillis() + + // Execute the view's query to get the current result set + val queryResult = session.sql(sparkSql) + + // Discover source tables from the query's logical plan and capture their current state + val sourceStates = collectSourceTableStates(queryResult.queryExecution.analyzed) + + // Build refresh state + val refreshState = new RefreshState( + view.currentVersion().versionId(), + sourceStates.asJava, + refreshStartTimestampMs) + val refreshStateJson = RefreshStateParser.toJson(refreshState) + + // Write results to storage table, replacing existing data + val storageTableRef = String.format( + "%s.%s.%s", + sparkCatalog.name(), + storageTableId.namespace().toString, + storageTableId.name()) + try { + queryResult + .writeTo(storageTableRef) + .option("snapshot-property." + RefreshState.REFRESH_STATE_SUMMARY_KEY, refreshStateJson) + .overwrite(functions.lit(true)) + } catch { + case e: NoSuchTableException => + throw new IllegalStateException( + s"Storage table $storageTableRef not found during refresh", + e) + } + + Nil + } + + private def collectSourceTableStates( + plan: org.apache.spark.sql.catalyst.plans.logical.LogicalPlan) + : List[org.apache.iceberg.view.SourceState] = { + val sparkCatalog = catalog.asInstanceOf[SparkCatalog] + val icebergCatalog = + sparkCatalog.icebergCatalog().asInstanceOf[org.apache.iceberg.catalog.Catalog] + val tables = scala.collection.mutable.LinkedHashSet.empty[String] + val states = scala.collection.mutable.ListBuffer.empty[org.apache.iceberg.view.SourceState] + + plan.collectLeaves().foreach { + case r: org.apache.spark.sql.execution.datasources.v2.DataSourceV2Relation + if r.catalog.exists(_.name() == sparkCatalog.name()) => + val tableIdent = r.identifier.get + val key = tableIdent.toString + if (!tables.contains(key)) { + tables.add(key) + val icebergId = + TableIdentifier.of(Namespace.of(tableIdent.namespace(): _*), tableIdent.name()) + try { + val table = icebergCatalog.loadTable(icebergId) + val snapshotId = + if (table.currentSnapshot() != null) { + table.currentSnapshot().snapshotId() Review Comment: +1, and I think this is a real gap, not just hypothetical. seems to be a TOCTOU gap in refresh. `collectSourceTableStates()` captures each source table's snapshot ID via a separate, explicit `catalog.loadTable()` call, which happens before the actual write executes via ` .writeTo().overwrite()`. But Iceberg's Spark integration resolves/pins the scan's snapshot at physical-plan build time — which happens when the write action triggers execution, not when `session.sql()` analyzes the query or when `collectSourceTableStates` runs separately. So if a concurrent commit lands on a source table in that window, the recorded refresh-state snapshot ID won't match what was actually scanned and written. Might be worth capturing the snapshot ID from the actual resolved scan (e.g. pin it explicitly via VERSION AS OF/snapshot option when building the query, or read it back from the executed plan) rather than re-resolving it independently after the fact. -- 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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