trait TableFeatureSupport extends AnyRef
Trait to be mixed into the Protocol case class to enable Table Features.
Protocol reader version 3 and writer version 7 start to support reader and writer table
features. Reader version 3 supports only reader-writer features in an explicit way,
by adding its name to readerFeatures. Similarly, writer version 7 supports only writer-only
or reader-writer features in an explicit way, by adding its name to writerFeatures.
When reading or writing a table, clients MUST respect all supported features.
See also the document of TableFeature for feature-specific terminologies.
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!=(arg0: Any): Boolean
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def
asInstanceOf[T0]: T0
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def
canDowngradeTo(to: Protocol, droppedFeatureName: String): Boolean
Determine whether this protocol can be safely downgraded to a new protocol
to.Determine whether this protocol can be safely downgraded to a new protocol
to. This includes the following:- The current protocol needs to support at least writer features. This is because protocol downgrade is only supported with table features.
- The protocol version can only be downgraded when there are no non-legacy table features.
- We can only remove one feature at a time.
- When downgrading protocol versions, the resulting versions must support exactly the same set of legacy features supported by the current protocol.
Note, this not an exhaustive list of downgrade rules. Rather, we check the most important downgrade invariants. We also perform checks during feature removal at AlterTableDropFeatureDeltaCommand.
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def
canTransitionTo(to: Protocol, op: Operation): Boolean
True if this protocol can be upgraded or downgraded to the 'to' protocol.
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def
canUpgradeTo(to: Protocol): Boolean
Determine whether this protocol can be safely upgraded to a new protocol
to.Determine whether this protocol can be safely upgraded to a new protocol
to. This means:- this protocol has reader protocol version less than or equals to
to. - this protocol has writer protocol version less than or equals to
to. - all features supported by this protocol are supported by
to.
Examples regarding feature status:
- from
[appendOnly]to[appendOnly]=> allowed - from
[appendOnly, changeDataFeed]to[appendOnly]=> not allowed - from
[appendOnly]to[appendOnly, changeDataFeed]=> allowed
- this protocol has reader protocol version less than or equals to
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def
clone(): AnyRef
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def
downgradeProtocolVersionsIfNeeded: Protocol
If the current protocol does not contain any non-legacy table features and the remaining set of legacy table features exactly matches a legacy protocol version, it downgrades the protocol to the minimum reader/writer versions required to support the protocol's legacy features.
If the current protocol does not contain any non-legacy table features and the remaining set of legacy table features exactly matches a legacy protocol version, it downgrades the protocol to the minimum reader/writer versions required to support the protocol's legacy features.
Note, when a table is initialized with table features (3, 7), by default there are no legacy features. After we remove the last native feature we downgrade the protocol to (1, 1).
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eq(arg0: AnyRef): Boolean
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lazy val
implicitlyAndExplicitlySupportedFeatures: Set[TableFeature]
Get all features that are supported by this protocol, implicitly and explicitly.
Get all features that are supported by this protocol, implicitly and explicitly. When the protocol supports table features, this method returns the same set of features as readerAndWriterFeatureNames; when the protocol does not support table features, this method becomes equivalent to implicitlySupportedFeatures.
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- @JsonIgnore()
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lazy val
implicitlySupportedFeatures: Set[TableFeature]
Get all features that are implicitly supported by this protocol, for example,
Protocol(1,2)implicitly supportsappendOnlyandinvariants.Get all features that are implicitly supported by this protocol, for example,
Protocol(1,2)implicitly supportsappendOnlyandinvariants. When this protocol is capable of requiring writer features, no feature can be implicitly supported.- Annotations
- @JsonIgnore()
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def
isFeatureSupported(feature: TableFeature): Boolean
Check if a
featureis supported by this protocol.Check if a
featureis supported by this protocol. This means either (a) the protocol does not support table features and implicitly supports the feature, or (b) the protocol supports table features and references the feature. -
final
def
isInstanceOf[T0]: Boolean
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def
merge(others: Protocol*): Protocol
Merge this protocol with multiple
protocolsto have the highest reader and writer versions plus all explicitly and implicitly supported features. -
final
def
ne(arg0: AnyRef): Boolean
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final
def
notify(): Unit
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final
def
notifyAll(): Unit
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lazy val
readerAndWriterFeatureNames: Set[String]
Get a set of all feature names in this protocol's
readerFeaturesandwriterFeaturesfield.Get a set of all feature names in this protocol's
readerFeaturesandwriterFeaturesfield. Returns an empty set when this protocol supports none of reader and writer features.- Annotations
- @JsonIgnore()
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lazy val
readerAndWriterFeatures: Seq[TableFeature]
Same as above but returns a sequence of TableFeature instead of a set of feature names.
Same as above but returns a sequence of TableFeature instead of a set of feature names.
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def
readerFeatureNames: Set[String]
Get all feature names in this protocol's
readerFeaturesfield.Get all feature names in this protocol's
readerFeaturesfield. Returns an empty set when this protocol does not support reader features. -
def
removeFeature(targetFeature: TableFeature): Protocol
Remove feature wrapper for removing either Reader/Writer or Writer features.
Remove feature wrapper for removing either Reader/Writer or Writer features. We assume the feature exists in the protocol. There is a relevant validation at AlterTableDropFeatureDeltaCommand. We also require targetFeature is removable.
When the feature to remove is the last explicit table feature of the table we also remove the TableFeatures feature and downgrade the protocol.
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def
supportsReaderFeatures: Boolean
Check if this protocol is capable of adding features into its
readerFeaturesfield. -
def
supportsWriterFeatures: Boolean
Check if this protocol is capable of adding features into its
writerFeaturesfield. -
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synchronized[T0](arg0: ⇒ T0): T0
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wait(): Unit
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def
wait(arg0: Long, arg1: Int): Unit
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def
wait(arg0: Long): Unit
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def
withFeature(feature: TableFeature): Protocol
Get a new Protocol object that has
featuresupported.Get a new Protocol object that has
featuresupported. Writer-only features will be added towriterFeaturesfield, and reader-writer features will be added toreaderFeaturesandwriterFeaturesfields.If
featureis already implicitly supported in the current protocol's legacy reader or writer protocol version, the new protocol will not modify the original protocol version, i.e., the feature will not be explicitly added to the protocol'sreaderFeaturesorwriterFeatures. This is to avoid unnecessary protocol upgrade for feature that it already supports. -
def
withFeatures(features: Iterable[TableFeature]): Protocol
Get a new Protocol object with multiple features supported.
Get a new Protocol object with multiple features supported.
See the documentation of withFeature for more information.
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def
writerFeatureNames: Set[String]
Get a set of all feature names in this protocol's
writerFeaturesfield.Get a set of all feature names in this protocol's
writerFeaturesfield. Returns an empty set when this protocol does not support writer features.