Package org.apache.cassandra.service.paxos.uncommitted

Class PaxosUncommittedIndex

java.lang.Object
org.apache.cassandra.service.paxos.uncommitted.PaxosUncommittedIndex
All Implemented Interfaces:
Index, PaxosUncommittedTracker.UpdateSupplier
public class PaxosUncommittedIndex extends Object implements Index, PaxosUncommittedTracker.UpdateSupplier
A 2i implementation made specifically for system.paxos that listens for changes to paxos state by interpreting mutations against system.paxos and updates the uncommitted tracker accordingly. No read expressions are supported by the index. This is implemented as a 2i so it can piggy back off the commit log and paxos table flushes, and avoid worrying about implementing a parallel log/flush system for the tracker and potential bugs there. It also means we don't have to worry about cases where the tracker can become out of sync with the paxos table due to failure/edge cases outside of the PaxosTableState class itself.

  • Field Details

  • Constructor Details

  • Method Details

    • indexMetadata

      public static IndexMetadata indexMetadata()

    • indexes

      public static Indexes indexes()

    • getInitializationTask

      public Callable<?> getInitializationTask()
      Description copied from interface: Index
      Return a task to perform any initialization work when a new index instance is created. This may involve costly operations such as (re)building the index, and is performed asynchronously by SecondaryIndexManager
      Specified by:
      getInitializationTask in interface Index
      Returns:
      a task to perform any necessary initialization work

    • getIndexMetadata

      public IndexMetadata getIndexMetadata()
      Description copied from interface: Index
      Returns the IndexMetadata which configures and defines the index instance. This should be the same object passed as the argument to setIndexMetadata.
      Specified by:
      getIndexMetadata in interface Index
      Returns:
      the index's metadata

    • getMetadataReloadTask

      public Callable<?> getMetadataReloadTask(IndexMetadata indexMetadata)
      Description copied from interface: Index
      Return a task to reload the internal metadata of an index. Called when the base table metadata is modified or when the configuration of the Index is updated Implementations should return a task which performs any necessary work to be done due to updating the configuration(s) such as (re)building etc. This task is performed asynchronously by SecondaryIndexManager
      Specified by:
      getMetadataReloadTask in interface Index
      Returns:
      task to be executed by the index manager during a reload

    • register

      public void register(IndexRegistry registry)
      Description copied from interface: Index
      An index must be registered in order to be able to either subscribe to update events on the base table and/or to provide Searcher functionality for reads. The double dispatch involved here, where the Index actually performs its own registration by calling back to the supplied IndexRegistry's own registerIndex method, is to make the decision as to whether or not to register an index belong to the implementation, not the manager.
      Specified by:
      register in interface Index
      Parameters:
      registry - the index registry to register the instance with

    • getBackingTable

      public Optional<ColumnFamilyStore> getBackingTable()
      Description copied from interface: Index
      If the index implementation uses a local table to store its index data, this method should return a handle to it. If not, an empty Optional should be returned. This exists to support legacy implementations, and should always be empty for indexes not belonging to a SingletonIndexGroup.
      Specified by:
      getBackingTable in interface Index
      Returns:
      an Optional referencing the Index's backing storage table if it has one, or Optional.empty() if not.

    • repairIterator

      public CloseableIterator<PaxosKeyState> repairIterator(TableId tableId, Collection<Range<Token>> ranges)
      Specified by:
      repairIterator in interface PaxosUncommittedTracker.UpdateSupplier

    • flushIterator

      public CloseableIterator<PaxosKeyState> flushIterator(Memtable flushing)
      Specified by:
      flushIterator in interface PaxosUncommittedTracker.UpdateSupplier

    • getBlockingFlushTask

      public Callable<?> getBlockingFlushTask()
      Description copied from interface: Index
      Return a task which performs a blocking flush of any in-memory index data to persistent storage, independent of any flush of the base table. Note that this method is only invoked outside of normal flushes: if there is no in-memory storage for this index, and it only extracts data on flush from the base table's Memtable, then it is safe to perform no work.
      Specified by:
      getBlockingFlushTask in interface Index
      Returns:
      task to be executed by the index manager to perform the flush.

    • getBlockingFlushTask

      public Callable<?> getBlockingFlushTask(Memtable paxos)
      Description copied from interface: Index
      Return a task which performs a blocking flush of the index's data corresponding to the provided base table's Memtable. This may extract any necessary data from the base table's Memtable as part of the flush. This version of the method is invoked whenever we flush the base table. If the index stores no in-memory data of its own, it is safe to only implement this method.
      Specified by:
      getBlockingFlushTask in interface Index
      Returns:
      task to be executed by the index manager to perform the flush.

    • getInvalidateTask

      public Callable<?> getInvalidateTask()
      Description copied from interface: Index
      Return a task which invalidates the index, indicating it should no longer be considered usable. This should include an clean up and releasing of resources required when dropping an index.
      Specified by:
      getInvalidateTask in interface Index
      Returns:
      task to be executed by the index manager to invalidate the index.

    • getTruncateTask

      public Callable<?> getTruncateTask(long truncatedAt)
      Description copied from interface: Index
      Return a task to truncate the index with the specified truncation timestamp. Called when the base table is truncated.
      Specified by:
      getTruncateTask in interface Index
      Parameters:
      truncatedAt - timestamp of the truncation operation. This will be the same timestamp used in the truncation of the base table.
      Returns:
      task to be executed by the index manager when the base table is truncated.

    • shouldBuildBlocking

      public boolean shouldBuildBlocking()
      Description copied from interface: Index
      Return true if this index can be built or rebuilt when the index manager determines it is necessary. Returning false enables the index implementation (or some other component) to control if and when SSTable data is incorporated into the index.

      This is called by SecondaryIndexManager in buildIndexBlocking, buildAllIndexesBlocking and rebuildIndexesBlocking where a return value of false causes the index to be exluded from the set of those which will process the SSTable data.

      Specified by:
      shouldBuildBlocking in interface Index
      Returns:
      if the index should be included in the set which processes SSTable data, false otherwise.

    • dependsOn

      public boolean dependsOn(ColumnMetadata column)
      Description copied from interface: Index
      Called to determine whether this index targets a specific column. Used during schema operations such as when dropping or renaming a column, to check if the index will be affected by the change. Typically, if an index answers that it does depend upon a column, then schema operations on that column are not permitted until the index is dropped or altered.
      Specified by:
      dependsOn in interface Index
      Parameters:
      column - the column definition to check
      Returns:
      true if the index depends on the supplied column being present; false if the column may be safely dropped or modified without adversely affecting the index

    • supportsExpression

      public boolean supportsExpression(ColumnMetadata column, Operator operator)
      Description copied from interface: Index
      Called to determine whether this index can provide a searcher to execute a query on the supplied column using the specified operator. This forms part of the query validation done before a CQL select statement is executed.
      Specified by:
      supportsExpression in interface Index
      Parameters:
      column - the target column of a search query predicate
      operator - the operator of a search query predicate
      Returns:
      true if this index is capable of supporting such expressions, false otherwise

    • customExpressionValueType

      public AbstractType<?> customExpressionValueType()
      Description copied from interface: Index
      If the index supports custom search expressions using the SELECT * FROM table WHERE expr(index_name, expression) syntax, this method should return the expected type of the expression argument. For example, if the index supports custom expressions as Strings, calls to this method should return UTF8Type.instance. If the index implementation does not support custom expressions, then it should return null.
      Specified by:
      customExpressionValueType in interface Index
      Returns:
      an the type of custom index expressions supported by this index, or an null if custom expressions are not supported.

    • getPostIndexQueryFilter

      public RowFilter getPostIndexQueryFilter(RowFilter filter)
      Description copied from interface: Index
      Transform an initial RowFilter into the filter that will still need to applied to a set of Rows after the index has performed it's initial scan. Used in ReadCommand#executeLocal to reduce the amount of filtering performed on the results of the index query.
      Specified by:
      getPostIndexQueryFilter in interface Index
      Parameters:
      filter - the intial filter belonging to a ReadCommand
      Returns:
      the (hopefully) reduced filter that would still need to be applied after the index was used to narrow the initial result set

    • getEstimatedResultRows

      public long getEstimatedResultRows()
      Description copied from interface: Index
      Return an estimate of the number of results this index is expected to return for any given query that it can be used to answer. Used in conjunction with indexes() and supportsExpression() to determine the most selective index for a given ReadCommand. Additionally, this is also used by StorageProxy.estimateResultsPerRange to calculate the initial concurrency factor for range requests
      Specified by:
      getEstimatedResultRows in interface Index
      Returns:
      the estimated average number of results a Searcher may return for any given query

    • validate

      public void validate(PartitionUpdate update, ClientState state) throws InvalidRequestException
      Description copied from interface: Index
      Called at write time to ensure that values present in the update are valid according to the rules of all registered indexes which will process it. The partition key as well as the clustering and cell values for each row in the update may be checked by index implementations
      Specified by:
      validate in interface Index
      Parameters:
      update - PartitionUpdate containing the values to be validated by registered Index implementations
      state - state related to the client connection
      Throws:
      InvalidRequestException

    • indexerFor

      public Index.Indexer indexerFor(DecoratedKey key, RegularAndStaticColumns columns, long nowInSec, WriteContext ctx, IndexTransaction.Type transactionType, Memtable memtable)
      Description copied from interface: Index
      Creates an new Indexer object for updates to a given partition.
      Specified by:
      indexerFor in interface Index
      Parameters:
      key - key of the partition being modified
      columns - the regular and static columns the created indexer will have to deal with. This can be empty as an update might only contain partition, range and row deletions, but the indexer is guaranteed to not get any cells for a column that is not part of columns.
      nowInSec - current time of the update operation
      ctx - WriteContext spanning the update operation
      transactionType - indicates what kind of update is being performed on the base data i.e. a write time insert/update/delete or the result of compaction
      memtable - current memtable that the write goes into. It's to make sure memtable and index memtable are in sync.
      Returns:
      the newly created indexer or null if the index is not interested by the update (this could be because the index doesn't care about that particular partition, doesn't care about that type of transaction, ...).

    • searcherFor

      public Index.Searcher searcherFor(ReadCommand command)
      Description copied from interface: Index
      Factory method for query time search helper.
      Specified by:
      searcherFor in interface Index
      Parameters:
      command - the read command being executed
      Returns:
      an Searcher with which to perform the supplied command