Definition
Action type for a timeline instantdef~timeline
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Key Instant action types performed include:COMMITS - `action type` which denotes an atomic write of a batch of records from an external source into a dataset def~table (see commit def~commit).CLEANS - `action type` which denotes a background activity that gets rid of older versions of files in the dataset def~table, that are no longer needed.DELTA_COMMIT - `action type` which denotes an atomic write of a batch of records into a Merge On Read def~merge-on-read (MOR)storage def~table-type of dataset def~table, where some/all of the data could be just written to delta logs (see commit def~commit).COMPACTION - `action type` which denotes a background activity to reconcile differential data structures within Hudi e.g: moving merging updates from row based delta log files to columnar onto def~base-files columnar file formats. Internally, compaction manifests as a special commit def~commit on the timeline (see timeline instantdef~timeline)ROLLBACK - `action type` denotes that a timeline instant def~timeline of `instant action type` commit/delta commit was unsuccessful & rolled back, removing any partial files produced during such a writeSAVEPOINT - `action type` marks certain file groups as “saved”, such that cleaner will not delete them. It helps restore the dataset def~table to a point on the timeline, in case of disaster/data recovery scenarios.
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Related concepts
- def~timeline
- instant state
- def~instant-time
- def~table
- def~commit
- dataset
- commit