Package org.apache.derby.iapi.sql.dictionary

Class ConglomerateDescriptor

  • All Implemented Interfaces:
    Dependable, Provider
    public final class ConglomerateDescriptor
extends UniqueTupleDescriptor
implements Provider
    The ConglomerateDescriptor class is used to get information about conglomerates for the purpose of optimization. A ConglomerateDescriptor can map to a base table, an index or a index backing a constraint. Multiple ConglomerateDescriptors can map to a single underlying store conglomerate, such as when multiple index definitions share a physical file. NOTE: The language module does not have to know much about conglomerates with this architecture. To get the cost of using a conglomerate, all it has to do is pass the ConglomerateDescriptor to the access methods, along with the predicate. What the access methods need from a ConglomerateDescriptor remains to be seen.
    Version:
    0.1

    • Field Detail

      • conglomerateNumber

        private long conglomerateNumber

      • name

        private java.lang.String name

      • columnNames

        private transient java.lang.String[] columnNames

      • indexable

        private final boolean indexable

      • forConstraint

        private final boolean forConstraint

      • uuid

        private final UUID uuid

      • tableID

        private final UUID tableID

      • schemaID

        private final UUID schemaID

    • Constructor Detail

      • ConglomerateDescriptor

        ConglomerateDescriptor​(DataDictionary dataDictionary,
                       long conglomerateNumber,
                       java.lang.String name,
                       boolean indexable,
                       IndexRowGenerator indexRowGenerator,
                       boolean forConstraint,
                       UUID uuid,
                       UUID tableID,
                       UUID schemaID)
        Constructor for a conglomerate descriptor.
        Parameters:
        dataDictionary - The data dictionary that this descriptor lives in
        conglomerateNumber - The number for the conglomerate we're interested in
        name - The name of the conglomerate, if any
        indexable - TRUE means the conglomerate is indexable, FALSE means it isn't
        indexRowGenerator - The descriptor of the index if it's not a heap
        forConstraint - TRUE means the conglomerate is an index backing up a constraint, FALSE means it isn't
        uuid - UUID for this conglomerate
        tableID - UUID for the table that this conglomerate belongs to
        schemaID - UUID for the schema that this conglomerate belongs to

    • Method Detail

      • getConglomerateNumber

        public long getConglomerateNumber()
        Gets the number for the conglomerate.
        Returns:
        A long identifier for the conglomerate

      • setConglomerateNumber

        public void setConglomerateNumber​(long conglomerateNumber)
        Set the conglomerate number. This is useful when swapping conglomerates, like for bulkInsert.
        Parameters:
        conglomerateNumber - The new conglomerate number.

      • getUUID

        public UUID getUUID()
        Gets the UUID String for the conglomerate.
        Specified by:
        getUUID in class UniqueTupleDescriptor
        Returns:
        The UUID String for the conglomerate

      • getTableID

        public UUID getTableID()
        Gets the UUID for the table that the conglomerate belongs to.
        Returns:
        The UUID String for the conglomerate

      • getSchemaID

        public UUID getSchemaID()
        Gets the UUID for the schema that the conglomerate belongs to.
        Returns:
        The UUID String for the schema that the conglomerate belongs to

      • isIndex

        public boolean isIndex()
        Tells whether the conglomerate can be used as an index.
        Returns:
        TRUE if the conglomerate can be used as an index, FALSE if not

      • isConstraint

        public boolean isConstraint()
        Tells whether the conglomerate is an index backing up a constraint.
        Returns:
        TRUE if the conglomerate is an index backing up a constraint, FALSE if not

      • getConglomerateName

        public java.lang.String getConglomerateName()
        Gets the name of the conglomerate. For heaps, this is null. For indexes, it is the index name.
        Returns:
        The name of the conglomerate, null if it's the heap for a table.

      • setConglomerateName

        public void setConglomerateName​(java.lang.String newName)
        Set the name of the conglomerate. Used only by rename index.
        Parameters:
        newName - The new name of the conglomerate.

      • getIndexDescriptor

        public IndexRowGenerator getIndexDescriptor()
        Gets the index row generator for this conglomerate, null if the conglomerate is not an index.
        Returns:
        The index descriptor for this conglomerate, if any.

      • setColumnNames

        public void setColumnNames​(java.lang.String[] columnNames)
        Set the column names for this conglomerate descriptor. This is useful for tracing the optimizer.
        Parameters:
        columnNames - 0-based array of column names.

      • getColumnNames

        public java.lang.String[] getColumnNames()
        Get the column names for this conglomerate descriptor. This is useful for tracing the optimizer.
        Returns:
        the column names for the conglomerate descriptor.

      • getDependableFinder

        public DependableFinder getDependableFinder()
        Description copied from interface: Dependable
        Get an object which can be written to disk and which, when read from disk, will find or reconstruct this in-memory Dependable.
        Specified by:
        getDependableFinder in interface Dependable
        Returns:
        the stored form of this provider

      • getObjectName

        public java.lang.String getObjectName()
        Return the name of this Provider. (Useful for errors.)
        Specified by:
        getObjectName in interface Dependable
        Returns:
        String The name of this provider.

      • getObjectID

        public UUID getObjectID()
        Get the provider's UUID
        Specified by:
        getObjectID in interface Dependable
        Returns:
        The provider's UUID

      • getClassType

        public java.lang.String getClassType()
        Get the provider's type.
        Specified by:
        getClassType in interface Dependable
        Returns:
        char The provider's type.

      • toString

        public java.lang.String toString()
        Convert the conglomerate descriptor to a String
        Overrides:
        toString in class java.lang.Object
        Returns:
        The conglomerate descriptor as a String

      • drop

        public ConglomerateDescriptor drop​(LanguageConnectionContext lcc,
                                   TableDescriptor td)
                            throws StandardException
        Drop this ConglomerateDescriptor when it represents an index. If this is the last desciptor for a physical index then the physical index (conglomerate) and its descriptor will be dropped.
        Parameters:
        lcc - Connection context to use for dropping
        td - TableDescriptor for the table to which this conglomerate belongs
        Returns:
        If the conglomerate described by this descriptor is an index conglomerate that is shared by multiple constraints/indexes, then we may have to create a new conglomerate to satisfy the constraints/indexes which remain after we drop the existing conglomerate. If that's needed then we'll return a conglomerate descriptor which describes what the new conglomerate must look like. It is then up to the caller of this method to create a new corresponding conglomerate. We don't create the index here because depending on who called us, it might not make sense to create it--esp. if we get here because of a DROP TABLE.
        Throws:
        StandardException

      • describeSharedConglomerate

        public ConglomerateDescriptor describeSharedConglomerate​(ConglomerateDescriptor[] descriptors,
                                                         boolean ignoreThis)
                                                  throws StandardException
        This method searches the received array of conglom descriptors to find all descriptors that currently share a physical conglom with "this". The method then searches within those sharing descriptors to find one that fully describes what a physical conglom would have to look like in order to support _all_ of the sharing descriptors in the array--esp. one that correctly enforces the uniqueness requirements for those descriptors.
        Parameters:
        descriptors - Array of conglomerate descriptors in which to search; the array may include an entry for "this"; it should not be null.
        ignoreThis - If true then we will NOT consider "this" conglomerate descriptor in our search. That is, we will find a descriptor to describe what a physical conglomerate would have to look like in order to support all sharing descriptors OTHER THAN this one.
        Returns:
        A conglomerate descriptor, pulled from the received array, that describes what a physical conglomerate would have to look to like in order to support all sharing descriptors (minus "this" if ignoreThis is true).
        Throws:
        StandardException