DESCRIBE HISTORY Command¶
Delta Lake can display the versions (history) of delta tables using the following high-level operators:
- DESCRIBE HISTORY SQL command
- DeltaTable.history
DESCRIBE HISTORY
(regardless of the variant: SQL or DeltaTable
API) is a mere wrapper around DeltaHistoryManager to access the history of a delta table.
Possible Cost Optimization on Microsoft Azure
When on Microsoft Azure, consider increasing spark.databricks.delta.history.maxKeysPerList configuration property to 5000
(which is the maximum number of blobs to return, including all BlobPrefix
elements, in a single List Blobs API call).
Metrics Reporting¶
Write metrics can be collected at transactional write based on history.metricsEnabled configuration property.