RyanBerti commented on code in PR #40615: URL: https://github.com/apache/spark/pull/40615#discussion_r1181936057
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/datasketchesAggregates.scala: ########## @@ -0,0 +1,368 @@ +/* + * 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.catalyst.expressions.aggregate + +import org.apache.datasketches.SketchesArgumentException +import org.apache.datasketches.hll.{HllSketch, Union} +import org.apache.datasketches.memory.Memory + +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.expressions.{ExpectsInputTypes, Expression, ExpressionDescription, Literal} +import org.apache.spark.sql.catalyst.trees.BinaryLike +import org.apache.spark.sql.types.{AbstractDataType, BinaryType, BooleanType, DataType, IntegerType, LongType, StringType, TypeCollection} +import org.apache.spark.unsafe.types.UTF8String + + +/** + * The HllSketchAgg function utilizes a Datasketches HllSketch instance to + * probabilistically count the number of unique values in a given column, and + * outputs the binary representation of the HllSketch. + * + * See [[https://datasketches.apache.org/docs/HLL/HLL.html]] for more information + * + * @param child child expression against which unique counting will occur + * @param lgConfigK the log-base-2 of K, where K is the number of buckets or slots for the sketch + */ +// scalastyle:off line.size.limit +@ExpressionDescription( + usage = """ + _FUNC_(expr, lgConfigK) - Returns the HllSketch's updateable binary representation. + `lgConfigK` (optional) the log-base-2 of K, with K is the number of buckets or + slots for the HllSketch. """, + examples = """ + Examples: + > SELECT hll_sketch_estimate(_FUNC_(col, 12)) FROM VALUES (1), (1), (2), (2), (3) tab(col); + 3 + """, + group = "agg_funcs", + since = "3.5.0") +// scalastyle:on line.size.limit +case class HllSketchAgg( + child: Expression, + lgConfigKExpression: Expression, + mutableAggBufferOffset: Int = 0, + inputAggBufferOffset: Int = 0) + extends TypedImperativeAggregate[HllSketch] with BinaryLike[Expression] with ExpectsInputTypes { + + // Hllsketch config - mark as lazy so that they're not evaluated during tree transformation. + + lazy val lgConfigK: Int = { + val lgConfigK = lgConfigKExpression.eval().asInstanceOf[Int] + // can't use HllUtil.checkLgK so replicate the check + if (lgConfigK < 4 || lgConfigK > 21) { + throw new SketchesArgumentException("Invalid lgConfigK value") + } else { Review Comment: Removed in updated companion object implementation. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
