common/thrift/Partitions.thrift

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namespace cpp impala
namespace java org.apache.impala.thrift

include "Exprs.thrift"

enum TPartitionType {
  UNPARTITIONED = 0

  // round-robin partition
  RANDOM = 1

  // unordered partition on a set of exprs
  // (partition bounds overlap)
  HASH_PARTITIONED = 2

  // ordered partition on a list of exprs
  // (partition bounds don't overlap)
  RANGE_PARTITIONED = 3

  // use the partitioning scheme of a Kudu table
  // TODO: this is a special case now because Kudu supports multilevel partition
  // schemes. We should add something like lists of TDataPartitions to reflect that
  // and then this can be removed. (IMPALA-5255)
  KUDU = 4
}

// Specification of how a single logical data stream is partitioned.
// This leaves out the parameters that determine the physical partition (for hash
// partitions, the number of partitions; for range partitions, the partitions'
// boundaries), which need to be specified by the enclosing structure/context.
struct TDataPartition {
  1: required TPartitionType type
  2: optional list<Exprs.TExpr> partition_exprs
}