trait SupportsDelta extends RowLevelOperation
A mix-in interface for RowLevelOperation
. Data sources can implement this interface
to indicate they support handling deltas of rows.
- Annotations
- @Experimental()
- Source
- SupportsDelta.java
- Since
3.4.0
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- SupportsDelta
- RowLevelOperation
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Abstract Value Members
- abstract def command(): Command
Returns the SQL command that is being performed.
Returns the SQL command that is being performed.
- Definition Classes
- RowLevelOperation
- abstract def newScanBuilder(options: CaseInsensitiveStringMap): ScanBuilder
Returns a
ScanBuilder
to configure aScan
for this row-level operation.Returns a
ScanBuilder
to configure aScan
for this row-level operation.Data sources fall into two categories: those that can handle a delta of rows and those that need to replace groups (e.g. partitions, files). Data sources that handle deltas allow Spark to quickly discard unchanged rows and have no requirements for input scans. Data sources that replace groups of rows can discard deleted rows but need to keep unchanged rows to be passed back into the source. This means that scans for such data sources must produce all rows in a group if any are returned. Some data sources will avoid pushing filters into files (file granularity), while others will avoid pruning files within a partition (partition granularity).
For example, if a data source can only replace partitions, all rows from a partition must be returned by the scan, even if a filter can narrow the set of changes to a single file in the partition. Similarly, a data source that can swap individual files must produce all rows from files where at least one record must be changed, not just rows that must be changed.
Data sources that replace groups of data (e.g. files, partitions) may prune entire groups using provided data source filters when building a scan for this row-level operation. However, such data skipping is limited as not all expressions can be converted into data source filters and some can only be evaluated by Spark (e.g. subqueries). Since rewriting groups is expensive, Spark allows group-based data sources to filter groups at runtime. The runtime filtering enables data sources to narrow down the scope of rewriting to only groups that must be rewritten. If the row-level operation scan implements
SupportsRuntimeV2Filtering
, Spark will execute a query at runtime to find which records match the row-level condition. The runtime group filter subquery will leverage a regular batch scan, which isn't required to produce all rows in a group if any are returned. The information about matching records will be passed back into the row-level operation scan, allowing data sources to discard groups that don't have to be rewritten.- Definition Classes
- RowLevelOperation
- abstract def newWriteBuilder(info: LogicalWriteInfo): DeltaWriteBuilder
Returns a
WriteBuilder
to configure aWrite
for this row-level operation.Returns a
WriteBuilder
to configure aWrite
for this row-level operation.Note that Spark will first configure the scan and then the write, allowing data sources to pass information from the scan to the write. For example, the scan can report which condition was used to read the data that may be needed by the write under certain isolation levels. Implementations may capture the built scan or required scan information and then use it while building the write.
- Definition Classes
- SupportsDelta → RowLevelOperation
- Annotations
- @Override()
- abstract def rowId(): Array[NamedReference]
Returns the row ID column references that should be used for row equality.
Concrete Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- final def ##: Int
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- final def ==(arg0: Any): Boolean
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- final def asInstanceOf[T0]: T0
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- def clone(): AnyRef
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- protected[lang]
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- @throws(classOf[java.lang.CloneNotSupportedException]) @IntrinsicCandidate() @native()
- def description(): String
Returns the description associated with this row-level operation.
Returns the description associated with this row-level operation.
- Definition Classes
- RowLevelOperation
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
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- final def getClass(): Class[_ <: AnyRef]
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- @IntrinsicCandidate() @native()
- def hashCode(): Int
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- @IntrinsicCandidate() @native()
- final def isInstanceOf[T0]: Boolean
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- final def ne(arg0: AnyRef): Boolean
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- final def notify(): Unit
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- @IntrinsicCandidate() @native()
- final def notifyAll(): Unit
- Definition Classes
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- Annotations
- @IntrinsicCandidate() @native()
- def representUpdateAsDeleteAndInsert(): Boolean
Controls whether to represent updates as deletes and inserts.
Controls whether to represent updates as deletes and inserts.
Data sources may choose to split updates into deletes and inserts to either better cluster and order the incoming delta of rows or to simplify the write process.
- def requiredMetadataAttributes(): Array[NamedReference]
Returns metadata attributes that are required to perform this row-level operation.
Returns metadata attributes that are required to perform this row-level operation.
Data sources that can use this method to project metadata columns needed for writing the data back (e.g. metadata columns for grouping data).
- Definition Classes
- RowLevelOperation
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
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- def toString(): String
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- final def wait(arg0: Long, arg1: Int): Unit
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- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
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- final def wait(): Unit
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- @throws(classOf[java.lang.InterruptedException])
Deprecated Value Members
- def finalize(): Unit
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- protected[lang]
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- Annotations
- @throws(classOf[java.lang.Throwable]) @Deprecated
- Deprecated
(Since version 9)