SnapshotDescriptor¶

SnapshotDescriptor is an abstraction of descriptions of the versioned snapshots of a delta table.

Contract¶

DeltaLog¶

deltaLog: DeltaLog

DeltaLog

Used when:

• GeneratedColumn is requested to generatePartitionFilters (for reporting purposes only)

Metadata¶

metadata: Metadata

Metadata

Used when:

• GeneratedColumn is requested to generatePartitionFilters
• SnapshotDescriptor is requested for the table schema
• TahoeFileIndex is requested for the partition schema

Protocol¶

protocol: Protocol

Protocol

Used when:

• GeneratedColumn is requested to generatePartitionFilters

Version¶

version: Long

Used when:

• TahoeFileIndex is requested for the string representation

Implementations¶

• Snapshot
• TahoeFileIndex

Table Schema¶

schema: StructType

schema requests the Metadata for the table schema.

schema is used when:

• DeltaCatalog is requested to alterTable
• DeltaTableV2 is requested for the table schema
• ShowTableColumnsCommand is executed
• TahoeLogFileIndex is requested to getSnapshot
• DeltaDataSource is requested for the source schema and createSource
• DeltaSourceBase is requested for the table schema, checkColumnMappingSchemaChangesOnStreamStartOnce (for reporting purposes)

isCatalogOwned¶

isCatalogOwned: Boolean

isCatalogOwned is enabled (true) when all the following holds:

1. version is at least 0
2. CatalogOwnedTableFeature is among the reader and writer features (of this Protocol)

isCatalogOwned is used when:

• OptimisticTransactionImpl is requested to isUCManagedTable
• Snapshot is requested to ensureCommitFilesBackfilled
• SnapshotManagement is requested to getUpdatedSnapshot and populateCommitCoordinator
• CreateDeltaTableCommand is requested to replaceMetadataIfNecessary
• DeltaReorgTableCommand command is executed
• OptimizeTableCommand command is executed
• VacuumCommand command is executed
• CatalogOwnedTableUtils is requested to populateTableCommitCoordinatorFromCatalog, validatePropertiesForAlterTableSetPropertiesDeltaCommand, validatePropertiesForAlterTableUnsetPropertiesDeltaCommand and validatePropertiesForCreateDeltaTableCommand
• CoordinatedCommitsUtils is requested to backfillWhenCoordinatedCommitsDisabled and commitFilesIterator
• TransactionHelper is requested to createCoordinatedCommitsStats and readSnapshotTableCommitCoordinatorClientOpt