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Caution
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FIXME Review sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala. |
Catalyst is a framework for manipulating trees of relational operators and expressions. It contains logical query plans that it can translate to executable code (as Spark RDDs).
Catalyst is an extensible query plan optimizer with constant folding, predicate pushdown, nullability (NULL value) propagation, vectorized Parquet decoder and whole-stage code generation optimization techniques.
Catalyst supports both rule-based and cost-based optimization.
Among the rule-based optimizations is nullability (NULL value) propagation.
RowEncoder is a factory object that maps StructType to ExpressionEncoder[Row]
It belongs to org.apache.spark.sql.catalyst.encoders package.