DescribeDeltaHistoryCommand Leaf Logical Command¶

DescribeDeltaHistoryCommand is a leaf RunnableCommand (Spark SQL) that uses DeltaHistoryManager for the commit history of a delta table.

DescribeDeltaHistoryCommand is an executable variant of DescribeDeltaHistory unary logical operator.

Creating Instance¶

DescribeDeltaHistoryCommand takes the following to be created:

• DeltaTableV2
• History Limit
• Output Schema Attributes

DescribeDeltaHistoryCommand is created when:

• DescribeDeltaHistory is requested to convert itself into an executable DescribeDeltaHistoryCommand

Executing Command¶

run(
  sparkSession: SparkSession): Seq[Row]

run requests the DeltaTableV2 for the DeltaLog that is requested for the DeltaHistoryManager.

In the end, run requests the DeltaHistoryManager for the commit history (for the latest limit versions).