[SPARK-37038][SQL][WIP] DSV2 Sample Push Down

docs/sql-data-sources-jdbc.md

@@ -246,6 +246,14 @@ logging into the data sources.
     <td>read</td>
   </tr>
 
+  <tr>
+    <td><code>pushDownTableSample</code></td>
+    <td><code>false</code></td>
+    <td>
+     The option to enable or disable TABLESAMPLE push-down into the JDBC data source. The default value is false, in which case Spark does not push down TABLESAMPLE to the JDBC data source. Otherwise, if value sets to true, TABLESAMPLE is pushed down to the JDBC data source.
+    </td>
+    <td>read</td>
+  </tr>
   <tr>
     <td><code>keytab</code></td>
     <td>(none)</td>

docs/sql-ref-ansi-compliance.md

@@ -491,6 +491,7 @@ Below is a list of all the keywords in Spark SQL.
 |REGEXP|non-reserved|non-reserved|not a keyword|
 |RENAME|non-reserved|non-reserved|non-reserved|
 |REPAIR|non-reserved|non-reserved|non-reserved|
+|REPEATABLE|non-reserved|non-reserved|non-reserved|
 |REPLACE|non-reserved|non-reserved|non-reserved|
 |RESET|non-reserved|non-reserved|non-reserved|
 |RESPECT|non-reserved|non-reserved|non-reserved|

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/v2/PostgresIntegrationSuite.scala

@@ -49,6 +49,8 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite with V2JDBCTes
   override def sparkConf: SparkConf = super.sparkConf
     .set("spark.sql.catalog.postgresql", classOf[JDBCTableCatalog].getName)
     .set("spark.sql.catalog.postgresql.url", db.getJdbcUrl(dockerIp, externalPort))
+    .set("spark.sql.catalog.postgresql.pushDownTableSample", "true")
+
   override def dataPreparation(conn: Connection): Unit = {}
 
   override def testUpdateColumnType(tbl: String): Unit = {
@@ -75,4 +77,6 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite with V2JDBCTes
     val expectedSchema = new StructType().add("ID", IntegerType, true, defaultMetadata)
     assert(t.schema === expectedSchema)
   }
+
+  override def supportsTableSample: Boolean = true
 }

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/v2/V2JDBCTest.scala

@@ -23,6 +23,7 @@ import org.apache.log4j.Level
 
 import org.apache.spark.sql.AnalysisException
 import org.apache.spark.sql.catalyst.analysis.{IndexAlreadyExistsException, NoSuchIndexException}
+import org.apache.spark.sql.catalyst.plans.logical.Sample
 import org.apache.spark.sql.connector.catalog.{Catalogs, Identifier, TableCatalog}
 import org.apache.spark.sql.connector.catalog.index.SupportsIndex
 import org.apache.spark.sql.connector.expressions.{FieldReference, NamedReference}
@@ -284,4 +285,32 @@ private[v2] trait V2JDBCTest extends SharedSparkSession with DockerIntegrationFu
       testIndexUsingSQL(s"$catalogName.new_table")
     }
   }
+
+  def supportsTableSample: Boolean = false
+
+  test("Test TABLESAMPLE") {
+    withTable(s"$catalogName.new_table") {
+      sql(s"CREATE TABLE $catalogName.new_table (col1 INT, col2 INT)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (1, 2)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (3, 4)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (5, 6)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (7, 8)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (9, 10)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (11, 12)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (13, 14)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (15, 16)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (17, 18)")
+      sql(s"INSERT INTO TABLE $catalogName.new_table values (19, 20)")
+      if (supportsTableSample) {
+        val df = sql(s"SELECT * FROM $catalogName.new_table TABLESAMPLE (BUCKET 6 OUT OF 10)" +
+          s" REPEATABLE (12345)")
+        df.explain(true)
+        val sample = df.queryExecution.optimizedPlan.collect {
+          case s: Sample => s
+        }
+        assert(sample.isEmpty)
+        assert(df.collect().length <= 7)
+      }
+    }
+  }
 }

sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4

@@ -674,7 +674,7 @@ joinCriteria
     ;
 
 sample
-    : TABLESAMPLE '(' sampleMethod? ')'
+    : TABLESAMPLE '(' sampleMethod? ')' (REPEATABLE '('seed=INTEGER_VALUE')')?
     ;
 
 sampleMethod
@@ -1194,6 +1194,7 @@ ansiNonReserved
     | REFRESH
     | RENAME
     | REPAIR
+    | REPEATABLE
     | REPLACE
     | RESET
     | RESPECT
@@ -1460,6 +1461,7 @@ nonReserved
     | REFRESH
     | RENAME
     | REPAIR
+    | REPEATABLE
     | REPLACE
     | RESET
     | RESPECT
@@ -1726,6 +1728,7 @@ REFERENCES: 'REFERENCES';
 REFRESH: 'REFRESH';
 RENAME: 'RENAME';
 REPAIR: 'REPAIR';
+REPEATABLE: 'REPEATABLE';
 REPLACE: 'REPLACE';
 RESET: 'RESET';
 RESPECT: 'RESPECT';

sql/catalyst/src/main/java/org/apache/spark/sql/connector/expressions/Expressions.java

@@ -190,4 +190,26 @@ public static SortOrder sort(Expression expr, SortDirection direction, NullOrder
   public static SortOrder sort(Expression expr, SortDirection direction) {
     return LogicalExpressions.sort(expr, direction, direction.defaultNullOrdering());
   }
+
+  /**
+   * Create a tableSample expression.
+   *
+   * @param methodName the sample method name
+   * @param lowerBound the lower-bound of the sampling probability (usually 0.0)
+   * @param upperBound the upper-bound of the sampling probability
+   * @param withReplacement whether to sample with replacement
+   * @param seed the random seed
+   * @return a TableSample
+   *
+   * @since 3.3.0
+   */
+  public static TableSample tableSample(
+      String methodName,
+      double lowerBound,
+      double upperBound,
+      boolean withReplacement,
+      long seed)  {
+    return LogicalExpressions.tableSample(
+      methodName, lowerBound, upperBound, withReplacement, seed);
+  }
 }

sql/catalyst/src/main/java/org/apache/spark/sql/connector/expressions/TableSample.java

@@ -0,0 +1,55 @@
+/*
+ * 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.connector.expressions;
+
+import org.apache.spark.annotation.Experimental;
+
+/**
+ * Represents a TableSample in the public expression API.
+ *
+ * @since 3.3.0
+ */
+@Experimental
+public interface TableSample extends Expression {
+
+  /**
+   * Returns the sample method name.
+   */
+  String methodName();
+
+  /**
+   * Returns the lower-bound of the sampling probability (usually 0.0).
+   */
+  double lowerBound();
+
+  /**
+   * Returns the upper-bound of the sampling probability. The expected fraction sampled
+   * will be ub - lb.
+   */
+  double upperBound();
+
+  /**
+   * Returns whether to sample with replacement.
+   */
+  boolean withReplacement();
+
+  /**
+   * Returns the random seed.
+   */
+  long seed();
+}

sql/catalyst/src/main/java/org/apache/spark/sql/connector/read/SupportsPushDownTableSample.java

@@ -0,0 +1,36 @@
+/*
+ * 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.connector.read;
+
+import org.apache.spark.annotation.Evolving;
+import org.apache.spark.sql.connector.expressions.TableSample;
+
+/**
+ * A mix-in interface for {@link Scan}. Data sources can implement this interface to
+ * push down SAMPLE.
+ *
+ * @since 3.3.0
+ */
+@Evolving
+public interface SupportsPushDownTableSample extends ScanBuilder {
+
+  /**
+   * Pushes down SAMPLE to the data source.
+   */
+  boolean pushTableSample(TableSample limit);
+}

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/parser/AstBuilder.scala

@@ -1180,29 +1180,35 @@ class AstBuilder extends SqlBaseBaseVisitor[AnyRef] with SQLConfHelper with Logg
    */
   private def withSample(ctx: SampleContext, query: LogicalPlan): LogicalPlan = withOrigin(ctx) {
     // Create a sampled plan if we need one.
-    def sample(fraction: Double): Sample = {
+    def sample(fraction: Double, seed: Long): Sample = {
       // The range of fraction accepted by Sample is [0, 1]. Because Hive's block sampling
       // function takes X PERCENT as the input and the range of X is [0, 100], we need to
       // adjust the fraction.
       val eps = RandomSampler.roundingEpsilon
       validate(fraction >= 0.0 - eps && fraction <= 1.0 + eps,
         s"Sampling fraction ($fraction) must be on interval [0, 1]",
         ctx)
-      Sample(0.0, fraction, withReplacement = false, (math.random * 1000).toInt, query)
+      Sample(0.0, fraction, withReplacement = false, seed, query)
     }
 
     if (ctx.sampleMethod() == null) {
       throw QueryParsingErrors.emptyInputForTableSampleError(ctx)
     }
 
+    val seed = if (ctx.seed != null) {
+      ctx.seed.getText.toLong
+    } else {
+      (math.random * 1000).toLong
+    }
+
     ctx.sampleMethod() match {
       case ctx: SampleByRowsContext =>
         Limit(expression(ctx.expression), query)
 
       case ctx: SampleByPercentileContext =>
         val fraction = ctx.percentage.getText.toDouble
         val sign = if (ctx.negativeSign == null) 1 else -1
-        sample(sign * fraction / 100.0d)
+        sample(sign * fraction / 100.0d, seed)
 
       case ctx: SampleByBytesContext =>
         val bytesStr = ctx.bytes.getText
@@ -1222,7 +1228,7 @@ class AstBuilder extends SqlBaseBaseVisitor[AnyRef] with SQLConfHelper with Logg
         }
 
       case ctx: SampleByBucketContext =>
-        sample(ctx.numerator.getText.toDouble / ctx.denominator.getText.toDouble)
+        sample(ctx.numerator.getText.toDouble / ctx.denominator.getText.toDouble, seed)
     }
   }
 

sql/catalyst/src/main/scala/org/apache/spark/sql/connector/expressions/expressions.scala

@@ -61,6 +61,15 @@ private[sql] object LogicalExpressions {
       nullOrdering: NullOrdering): SortOrder = {
     SortValue(reference, direction, nullOrdering)
   }
+
+  def tableSample(
+      methodName: String,
+      lowerBound: Double,
+      upperBound: Double,
+      withReplacement: Boolean,
+      seed: Long): TableSample = {
+    TableSampleValue(methodName: String, lowerBound, upperBound, withReplacement, seed)
+  }
 }
 
 /**
@@ -357,3 +366,14 @@ private[sql] object SortValue {
       None
   }
 }
+
+private[sql] final case class TableSampleValue(
+    methodName: String,
+    lowerBound: Double,
+    upperBound: Double,
+    withReplacement: Boolean,
+    seed: Long) extends TableSample {
+
+  override def describe(): String = s"$methodName $lowerBound $lowerBound $upperBound" +
+    s" $withReplacement $seed"
+}

sql/core/src/main/scala/org/apache/spark/sql/execution/DataSourceScanExec.scala

@@ -31,6 +31,7 @@ import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.plans.QueryPlan
 import org.apache.spark.sql.catalyst.plans.physical.{HashPartitioning, Partitioning, UnknownPartitioning}
 import org.apache.spark.sql.catalyst.util.truncatedString
+import org.apache.spark.sql.connector.expressions.TableSample
 import org.apache.spark.sql.connector.expressions.aggregate.Aggregation
 import org.apache.spark.sql.execution.datasources._
 import org.apache.spark.sql.execution.datasources.parquet.{ParquetFileFormat => ParquetSource}
@@ -104,6 +105,7 @@ case class RowDataSourceScanExec(
     filters: Set[Filter],
     handledFilters: Set[Filter],
     aggregation: Option[Aggregation],
+    sample: Option[TableSample],
     rdd: RDD[InternalRow],
     @transient relation: BaseRelation,
     tableIdentifier: Option[TableIdentifier])
@@ -153,7 +155,10 @@ case class RowDataSourceScanExec(
       "ReadSchema" -> requiredSchema.catalogString,
       "PushedFilters" -> seqToString(markedFilters.toSeq),
       "PushedAggregates" -> aggString,
-      "PushedGroupby" -> groupByString)
+      "PushedGroupby" -> groupByString) ++
+      sample.map(v => "PushedSample" ->
+        s"SAMPLE ${v.methodName} ${v.lowerBound} ${v.upperBound} ${v.withReplacement} ${v.seed}"
+      )
   }
 
   // Don't care about `rdd` and `tableIdentifier` when canonicalizing.

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala

@@ -336,6 +336,7 @@ object DataSourceStrategy
         Set.empty,
         Set.empty,
         None,
+        null,
         toCatalystRDD(l, baseRelation.buildScan()),
         baseRelation,
         None) :: Nil
@@ -410,6 +411,7 @@ object DataSourceStrategy
         pushedFilters.toSet,
         handledFilters,
         None,
+        null,
         scanBuilder(requestedColumns, candidatePredicates, pushedFilters),
         relation.relation,
         relation.catalogTable.map(_.identifier))
@@ -433,6 +435,7 @@ object DataSourceStrategy
         pushedFilters.toSet,
         handledFilters,
         None,
+        null,
         scanBuilder(requestedColumns, candidatePredicates, pushedFilters),
         relation.relation,
         relation.catalogTable.map(_.identifier))

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCOptions.scala

@@ -191,6 +191,9 @@ class JDBCOptions(
   // An option to allow/disallow pushing down aggregate into JDBC data source
   val pushDownAggregate = parameters.getOrElse(JDBC_PUSHDOWN_AGGREGATE, "false").toBoolean
 
+  // An option to allow/disallow pushing down TABLESAMPLE into JDBC data source
+  val pushDownTableSample = parameters.getOrElse(JDBC_PUSHDOWN_TABLESAMPLE, "false").toBoolean
+
   // The local path of user's keytab file, which is assumed to be pre-uploaded to all nodes either
   // by --files option of spark-submit or manually
   val keytab = {
@@ -266,6 +269,7 @@ object JDBCOptions {
   val JDBC_SESSION_INIT_STATEMENT = newOption("sessionInitStatement")
   val JDBC_PUSHDOWN_PREDICATE = newOption("pushDownPredicate")
   val JDBC_PUSHDOWN_AGGREGATE = newOption("pushDownAggregate")
+  val JDBC_PUSHDOWN_TABLESAMPLE = newOption("pushDownTableSample")
   val JDBC_KEYTAB = newOption("keytab")
   val JDBC_PRINCIPAL = newOption("principal")
   val JDBC_TABLE_COMMENT = newOption("tableComment")