Class OpenBTree

java.lang.Object
org.apache.derby.impl.store.access.btree.OpenBTree
Direct Known Subclasses:
BTreeController, BTreeCostController, BTreeScan

public class OpenBTree extends Object
An open b-tree contains fields and methods common to scans and controllers.

Concurrency Notes

An instance of an open b-tree is owned by a single context. The b-tree code assumes that the context ensures that only one thread at a time is using the open b-tree. The open b-tree itself does not enforce or check this.

  • Field Details

    • init_conglomerate

      private BTree init_conglomerate
      The following group of fields are all basic input parameters which are provided by the calling code when doing any sort of operation requiring an open conglomerate (openScan(), open(), openCostController(), ...). These are just saved values from what was initially input.
    • init_xact_manager

      private TransactionManager init_xact_manager
      The TransactionManager that open'd this btree. In the case of Internal transactions used by split this will be the internal transaction, and init_open_user_scans will be the user transaction that began the internal transaction.
    • init_rawtran

      private Transaction init_rawtran
    • init_openmode

      private int init_openmode
      The ContainerHandle mode the container is opened with. Remember this so that if the BTree needs to do SMO with another transaction, it would open the container with the same mode.
    • init_lock_level

      protected int init_lock_level
      Table or page locking?
    • init_hold

      private boolean init_hold
    • init_btree_locking_policy

      private BTreeLockingPolicy init_btree_locking_policy
      The Locking Policy to use for for access to this btree.
    • container

      protected ContainerHandle container
      The (open) container which contains the b-tree.
    • err_containerid

      protected long err_containerid
      The conglomerate containerid for error reporting.
    • init_open_user_scans

      protected TransactionManager init_open_user_scans
      The user transaction that opened this B-tree.
    • btree_undo

      protected LogicalUndo btree_undo
    • runtime_mem

      protected OpenConglomerateScratchSpace runtime_mem
      scratch space used for stuff like templates, export rows, ...
  • Constructor Details

    • OpenBTree

      public OpenBTree()
  • Method Details

    • getXactMgr

      public final TransactionManager getXactMgr()
      Public Accessors of This class:
    • getRawTran

      public final Transaction getRawTran()
    • getLockLevel

      public final int getLockLevel()
    • getContainer

      public final ContainerHandle getContainer()
    • getOpenMode

      public final int getOpenMode()
    • getConglomerate

      public final BTree getConglomerate()
    • getHold

      public final boolean getHold()
    • getLockingPolicy

      public final BTreeLockingPolicy getLockingPolicy()
    • setLockingPolicy

      public final void setLockingPolicy(BTreeLockingPolicy policy)
    • isClosed

      public final boolean isClosed()
    • getRuntimeMem

      public final OpenConglomerateScratchSpace getRuntimeMem()
    • getEstimatedRowCount

      public long getEstimatedRowCount() throws StandardException
      Get the total estimated number of rows in the container.

      The number is a rough estimate and may be grossly off. In general the server will cache the row count and then occasionally write the count unlogged to a backing store. If the system happens to shutdown before the store gets a chance to update the row count it may wander from reality.

      This call is currently only supported on Heap conglomerates, it will throw an exception if called on btree conglomerates.

      Returns:
      The total estimated number of rows in the conglomerate.
      Throws:
      StandardException - Standard exception policy.
    • setEstimatedRowCount

      public void setEstimatedRowCount(long count) throws StandardException
      Set the total estimated number of rows in the container.

      Often, after a scan, the client of RawStore has a much better estimate of the number of rows in the container than what store has. For instance if we implement some sort of update statistics command, or just after a create index a complete scan will have been done of the table. In this case this interface allows the client to set the estimated row count for the container, and store will use that number for all future references.

      This call is currently only supported on Heap conglomerates, it will throw an exception if called on btree conglomerates.

      Parameters:
      count - the estimated number of rows in the container.
      Throws:
      StandardException - Standard exception policy.
    • checkConsistency

      public void checkConsistency() throws StandardException
      Check consistency of a btree.

      Read in root and check consistency of entire tree. Currently raises sanity check errors.

      RESOLVE (mikem) if this is to be supported in non-sanity servers what should it do?

      Throws:
      StandardException - Standard exception policy.
    • isTableLocked

      public boolean isTableLocked()
      is the open btree table locked?
    • init

      public void init(TransactionManager open_user_scans, TransactionManager xact_manager, ContainerHandle input_container, Transaction rawtran, boolean hold, int open_mode, int lock_level, BTreeLockingPolicy btree_locking_policy, BTree conglomerate, LogicalUndo undo, DynamicCompiledOpenConglomInfo dynamic_info) throws StandardException
      Initialize the open conglomerate.

      If container is null, open the container, otherwise use the container passed in. The container is always opened with no locking, it is up to the caller to make the appropriate container locking call.

      Parameters:
      open_user_scans - The user transaction which opened this btree.
      xact_manager - The current transaction, usually the same as "open_user_scans", but in the case of split it is the internal xact nested below the user xact.
      input_container - The open container holding the index, if it is already open, else null which will mean this routine will open it.
      rawtran - The current raw store transaction.
      open_mode - The opening mode for the ContainerHandle.
      conglomerate - Readonly description of the conglomerate.
      undo - Logical undo object to associate with all updates done on this open btree.
      Throws:
      StandardException - Standard exception policy.
    • reopen

      public ContainerHandle reopen() throws StandardException
      Open the container after it has been closed previously.

      Open the container, obtaining necessary locks. Most work is actually done by RawStore.openContainer(). Will only reopen() if the container is not already open.

      Throws:
      StandardException - Standard exception policy.
    • close

      public void close() throws StandardException
      Close the open conglomerate.
      Throws:
      StandardException
    • isIndexableRowConsistent

      void isIndexableRowConsistent(DataValueDescriptor[] row) throws StandardException
      Check if all the columns are Indexable and Storable. Eventually this routine could check whether all the types were right also.
      Throws:
      StandardException - Standard Exception Policy.
    • getContainerHandle

      public ContainerHandle getContainerHandle()
      Return the container handle.

      Returns:
      The open container handle of the btree.
    • getHeight

      public int getHeight() throws StandardException
      get height of the tree.

      Read in root and return the height (number of levels) of the tree. The level of a tree is 0 in the leaf and increases by 1 for each level of the tree as you go up the tree.

      Throws:
      StandardException - Standard exception policy.
    • debugConglomerate

      public void debugConglomerate() throws StandardException
      Dump information about tree into the log.

      Traverse the tree dumping info about tree into the log.

      Throws:
      StandardException - Standard exception policy.
    • test_errors

      public static boolean test_errors(OpenBTree open_btree, String debug_string, BTreeRowPosition pos, BTreeLockingPolicy btree_locking_policy, LeafControlRow leaf, boolean input_latch_released) throws StandardException
      Testing infrastructure to cause unusual paths through the code.

      Through the use of debug flags allow test code to cause otherwise hard to cause paths through the code.

      Parameters:
      pos - the current scan position if the condition simulated by this call would have resulted in the position being saved
      Returns:
      whether the latch has been released by this routine.
      Throws:
      StandardException - Standard exception policy.
    • getSpaceInfo

      public SpaceInfo getSpaceInfo() throws StandardException
      Throws:
      StandardException
    • getColumnSortOrderInfo

      public boolean[] getColumnSortOrderInfo() throws StandardException
      Throws:
      StandardException