org.apache.cassandra.index.transactions

## Interface UpdateTransaction

- All Superinterfaces:
    IndexTransaction

      public interface UpdateTransaction
      extends IndexTransaction

  Handling of index updates on the write path. Instances of an UpdateTransaction are scoped to a single partition update A new instance is used for every write, obtained from the newUpdateTransaction(PartitionUpdate) method. Likewise, a single CleanupTransaction instance is used for each partition processed during a compaction or cleanup. We make certain guarantees about the lifecycle of each UpdateTransaction instance. Namely that start() will be called before any other method, and commit() will be called at the end of the update. Each instance is initialized with 1..many Index.Indexer instances, one per registered Index. As with the transaction itself, these are scoped to a specific partition update, so implementations can be assured that all indexing events they receive relate to the same logical operation. onPartitionDelete(), onRangeTombstone(), onInserted() and onUpdated() calls may arrive in any order, but this should have no impact for the Indexers being notified as any events delivered to a single instance necessarily relate to a single partition. The typical sequence of events during a Memtable update would be: start() -- no-op, used to notify Indexers of the start of the transaction onPartitionDeletion(dt) -- if the PartitionUpdate implies one onRangeTombstone(rt)* -- for each in the PartitionUpdate, if any then: onInserted(row)* -- called for each Row not already present in the Memtable onUpdated(existing, updated)* -- called for any Row in the update for where a version was already present in the Memtable. It's important to note here that existing is the previous row from the Memtable and updated is the final version replacing it. It is *not* the incoming row, but the result of merging the incoming and existing rows. commit() -- finally, finish is called when the new Partition is swapped into the Memtable

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface org.apache.cassandra.index.transactions.IndexTransaction

      `IndexTransaction.Type`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static UpdateTransaction` | `NO_OP`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `onInserted(Row row)`
    `void` | `onPartitionDeletion(DeletionTime deletionTime)`
    `void` | `onRangeTombstone(RangeTombstone rangeTombstone)`
    `void` | `onUpdated(Row existing, Row updated)`

    - ### Methods inherited from interface org.apache.cassandra.index.transactions.IndexTransaction

      `commit, start`

- - ### Field Detail

    - #### NO_OP

          static final UpdateTransaction NO_OP

  - ### Method Detail

    - #### onPartitionDeletion

          void onPartitionDeletion(DeletionTime deletionTime)

    - #### onRangeTombstone

          void onRangeTombstone(RangeTombstone rangeTombstone)

    - #### onInserted

          void onInserted(Row row)

    - #### onUpdated

          void onUpdated(Row existing,
                         Row updated)

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