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MLnick
/ HyperLogLogStoreUDAF.scala
Last active
March 16, 2022 05:31
Experimenting with Spark SQL UDAF - HyperLogLog UDAF for distinct counts, that stores the actual HLL for each row to allow further aggregation
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| class HyperLogLogStoreUDAF extends UserDefinedAggregateFunction { | |
| override def inputSchema = new StructType() | |
| .add("stringInput", BinaryType) | |
| override def update(buffer: MutableAggregationBuffer, input: Row) = { | |
| // This input Row only has a single column storing the input value in String (or other Binary data). | |
| // We only update the buffer when the input value is not null. | |
| if (!input.isNullAt(0)) { | |
| if (buffer.isNullAt(0)) { |
tzachz
/ CombineMaps.scala
Last active
January 26, 2023 04:31
Apache Spark UserDefinedAggregateFunction combining maps
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| import org.apache.spark.SparkContext | |
| import org.apache.spark.sql.expressions.{MutableAggregationBuffer, UserDefinedAggregateFunction} | |
| import org.apache.spark.sql.types._ | |
| import org.apache.spark.sql.{Column, Row, SQLContext} | |
| /*** | |
| * UDAF combining maps, overriding any duplicate key with "latest" value | |
| * @param keyType DataType of Map key | |
| * @param valueType DataType of Value key | |
| * @param merge function to merge values of identical keys |