DescribeDeltaHistoryCommand¶

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

DescribeDeltaHistoryCommand is used for DESCRIBE HISTORY SQL command.

Creating Instance¶

DescribeDeltaHistoryCommand takes the following to be created:

• (optional) Directory
• (optional) TableIdentifier
• (optional) Number of commits to display
• Output Attributes (default: CommitInfo)

DescribeDeltaHistoryCommand is created for:

• DESCRIBE HISTORY SQL command (that uses DeltaSqlAstBuilder to parse DESCRIBE HISTORY SQL command)

Executing Command¶

run(
  sparkSession: SparkSession): Seq[Row]

run is part of the RunnableCommand (Spark SQL) abstraction.

run creates a Hadoop Path to (the location of) the delta table (based on DeltaTableIdentifier).

run creates a DeltaLog for the delta table.

run requests the DeltaLog for the DeltaHistoryManager that is requested for the commit history.