Hi
I am encountering a Singleton object not available error when trying to add
the parameter *spark.cassandra.sql.pushdown.additionalClasses* to push all
filters to Cassandra. Please find the code and error message below:
*Code:*
package com.common.reader
import org.apache.spark.sql.{DataFrame, SparkSession}
import com.datastax.spark.connector.cql.TableDef
import org.apache.spark.SparkConf
import org.apache.spark.sql.cassandra.{AnalyzedPredicates,
CassandraPredicateRules, CassandraSourceRelation}
class CassandraReader(spark: SparkSession) {
def read(table: String, keyspace: String, path: String, inc_field:
String): DataFrame =
{
var df = spark
.read
.format("org.apache.spark.sql.cassandra")
.option( "table",table)
.option( "keyspace",keyspace)
.option("spark.cassandra.sql.pushdown.additionalClasses","com.common.reader.PushdownEverything")
// .options(Map(
// "keyspace" -> keyspace,
// "table" -> table,
// "pushdown" -> "true",
// CassandraSourceRelation.AdditionalCassandraPushDownRulesParam.name
-> "com.common.reader.PushdownEverything"))
.load
if (inc_field.nonEmpty)
{
val max_inc_value= spark.sql(s"select max(${inc_field}) from
delta.`${path}`").first.get(0)
println(max_inc_value)
df = df.filter(s"${inc_field}>'${max_inc_value}'")
}
df
}
}
object PushdownEverything extends CassandraPredicateRules {
override def apply(
predicates: AnalyzedPredicates,
tableDef: TableDef,
sparkConf: SparkConf): AnalyzedPredicates = {
AnalyzedPredicates(predicates.handledByCassandra ++
predicates.handledBySpark, Set.empty)
}
}
*Error:*
IllegalArgumentException: Singleton object not available:
com.common.reader.PushdownEverything
Caused by: ClassNotFoundException: com.common.reader.PushdownEverything
at
com.datastax.spark.connector.util.ReflectionUtil$.findGlobalObject(ReflectionUtil.scala:54)
at
com.datastax.spark.connector.datasource.CassandraScanBuilder.$anonfun$additionalRules$1(CassandraScanBuilder.scala:102)
at
scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:286)
at
scala.collection.IndexedSeqOptimized.foreach(IndexedSeqOptimized.scala:36)
at
scala.collection.IndexedSeqOptimized.foreach$(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:198)
at scala.collection.TraversableLike.map(TraversableLike.scala:286)
at scala.collection.TraversableLike.map$(TraversableLike.scala:279)
at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:198)
at
com.datastax.spark.connector.datasource.CassandraScanBuilder.additionalRules(CassandraScanBuilder.scala:102)
at
com.datastax.spark.connector.datasource.CassandraScanBuilder.pushFilters(CassandraScanBuilder.scala:76)
at
org.apache.spark.sql.execution.datasources.v2.PushDownUtils$.pushFilters(PushDownUtils.scala:66)
at
org.apache.spark.sql.execution.datasources.v2.V2ScanRelationPushDown$$anonfun$pushDownFilters$1.applyOrElse(V2ScanRelationPushDown.scala:73)
at
org.apache.spark.sql.execution.datasources.v2.V2ScanRelationPushDown$$anonfun$pushDownFilters$1.applyOrElse(V2ScanRelationPushDown.scala:60)
at
org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$transformDownWithPruning$1(TreeNode.scala:465)
at
org.apache.spark.sql.catalyst.trees.CurrentOrigin$.withOrigin(origin.scala:69)
at
org.apache.spark.sql.catalyst.trees.TreeNode.transformDownWithPruning(TreeNode.scala:465)
at org.apache.spark.sql.catalyst.plans.logical.LogicalPlan.org
$apache$spark$sql$catalyst$plans$logical$AnalysisHelper$$super$transformDownWithPruning(LogicalPlan.scala:39)
at
org.apache.spark.sql.catalyst.plans.logical.AnalysisHelper.transformDownWithPruning(AnalysisHelper.scala:339)
at
org.apache.spark.sql.catalyst.plans.logical.AnalysisHelper.transformDownWithPruning$(AnalysisHelper.scala:335)
at
org.apache.spark.sql.catalyst.plans.logical.LogicalPlan.transformDownWithPruning(LogicalPlan.scala:39)
at
org.apache.spark.sql.catalyst.plans.logical.LogicalPlan.transformDownWithPruning(LogicalPlan.scala:39)
at
org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$transformDownWithPruning$3(TreeNode.scala:470)
at
org.apache.spark.sql.catalyst.trees.UnaryLike.mapChildren(TreeNode.scala:1267)
at
org.apache.spark.sql.catalyst.trees.UnaryLike.mapChildren$(TreeNode.scala:1266)
at
org.apache.spark.sql.execution.datasources.WriteFiles.mapChildren(WriteFiles.scala:58)
at
org.apache.spark.sql.catalyst.trees.TreeNode.transformDownWithPruning(TreeNode.scala:470)
at
org.apache.spark.sql.catalyst.plans.logical.LogicalPlan.org$apache$spark$sql$catalyst$plans$logical$AnalysisHelper$$super$transformDownWithPruning(LogicalPlan.scala:39)
....
