Class BTreeController

    • Field Detail

      • get_insert_row_lock

        boolean get_insert_row_lock
        Whether to get lock on the row being inserted, usually this lock has already been gotten when the row was inserted into the base table.
    • Constructor Detail

      • BTreeController

        public BTreeController()
    • Method Detail

      • reclaim_deleted_rows

        private boolean reclaim_deleted_rows​(OpenBTree open_btree,
                                             long pageno)
                                      throws StandardException
        Attempt to reclaim committed deleted rows from the page.

        Get exclusive latch on page, and then loop backward through page searching for deleted rows which are committed. The routine assumes that it is called from a transaction which cannot have deleted any rows on the page. For each deleted row on the page it attempts to get an exclusive lock on the deleted row, NOWAIT. If it succeeds, and since this row did not delete the row then the row must have been deleted by a transaction which has committed, so it is safe to purge the row. It then purges the row from the page.

        Note that this routine may remove all rows from the page, it will not attempt a merge in this situation. This is because this routine is called from split which is attempting an insert on the given page, so it would be a waste to merge the page only to split it again to allow the insert of the row causing the split.

        Parameters:
        open_btree - The already open btree to use to get latch on page.
        pageno - The page number of the leaf to attempt the reclaim on.
        Returns:
        true if at least one row was purged. If true, then the routine will leave the page latched, and the caller will release the latch by committing or aborting the transaction. The latch must be held to end transaction to insure space on the page remains available for a undo of the purge.
        Throws:
        StandardException - Standard exception policy.
      • start_xact_and_dosplit

        private long start_xact_and_dosplit​(boolean attempt_to_reclaim_deleted_rows,
                                            long leaf_pageno,
                                            DataValueDescriptor[] scratch_template,
                                            DataValueDescriptor[] rowToInsert,
                                            int flag)
                                     throws StandardException
        Start an internal transaction and do the split.

        This routine starts a new transaction, and handles any errors that may come during the transaction. This transation must not obtain any locks as they are likely to conflict with the current user transaction.

        If attempt_to_reclaim_deleted_rows is true this routine will attempt to reclaim space on the leaf page input, by purging committed deleted rows from the leaf. If it succeeds in purging at least one row, then it will commit the internal transaction and return without actually performing a split.

        Parameters:
        scratch_template - A scratch template used to search a page.
        rowToInsert - The row to insert, make sure during split to make room for this row.
        Throws:
        StandardException - Standard exception policy.
      • comparePreviousRecord

        private int comparePreviousRecord​(int slot,
                                          LeafControlRow leaf,
                                          DataValueDescriptor[] rows,
                                          DataValueDescriptor[] oldRows)
                                   throws StandardException
        Compares the oldrow with the one at 'slot' or the one left to it. If the slot is first slot it will move to the left sibiling of the 'leaf' and will compare with the record from the last slot.
        Parameters:
        slot - slot number to start with
        leaf - LeafControlRow of the current page
        rows - DataValueDescriptot array to fill it with fetched values
        Returns:
        0 if no duplicate 1 if duplicate 2 if rescan required
        Throws:
        StandardException
      • compareNextRecord

        private int compareNextRecord​(int slot,
                                      LeafControlRow leaf,
                                      DataValueDescriptor[] rows,
                                      DataValueDescriptor[] oldRows)
                               throws StandardException
        Compares the new record with the one at slot or the one right to it. If the slot is last slot in the page it will move to the right to sibling of the leaf and will compare with the record from the last slot.
        Parameters:
        slot - slot number to start with
        leaf - LeafControlRow of the current page
        rows - DataValueDescriptot array to fill it with fetched values
        Returns:
        0 if no duplicate 1 if duplicate 2 if rescan required
        Throws:
        StandardException
      • compareRowsForInsert

        private int compareRowsForInsert​(DataValueDescriptor[] originalRow,
                                         DataValueDescriptor[] newRow,
                                         LeafControlRow leaf,
                                         int slot)
                                  throws StandardException
        Compares two rows for insert. If the two rows are not equal, NO_MATCH is returned. Otherwise, it tries to get a lock on the row in the tree. If the lock is obtained without waiting, MATCH_FOUND is returned (even if the row has been deleted). Otherwise, RESCAN_REQUIRED is returned to indicate that the latches have been released and the B-tree must be rescanned. If MATCH_FOUND is returned, the caller should check whether the row has been deleted. If so, it may have to move to check the adjacent rows to be sure that there is no non-deleted duplicate row. If MATCH_FOUND or RESCAN_REQUIRED is returned, the transaction will hold an update lock on the specified record when the method returns. Note! This method should only be called when the index is almost unique (that is, a non-unique index backing a unique constraint).
        Parameters:
        originalRow - row from the tree
        newRow - row to be inserted
        leaf - leaf where originalRow resides
        slot - slot where originalRow
        Returns:
        NO_MATCH if no duplicate is found, MATCH_FOUND if a duplicate is found, or RESCAN_REQUIRED if the B-tree must be rescanned
        Throws:
        StandardException
      • compareLeftAndRightSiblings

        private int compareLeftAndRightSiblings​(DataValueDescriptor[] rowToInsert,
                                                int insert_slot,
                                                LeafControlRow targetleaf)
                                         throws StandardException
        Compares immidiate left and right records to check for duplicates. This methods compares new record (being inserted) with the record in immidate left and right postion to see if its duplicate (only for almost unique index and for non null keys)
        Parameters:
        rowToInsert - row being inserted
        insert_slot - slot where rowToInsert is being inserted
        targetleaf - page where rowToInsert
        Returns:
        0 if no duplicate 1 if duplicate 2 if rescan required
        Throws:
        StandardException
      • doIns

        private int doIns​(DataValueDescriptor[] rowToInsert)
                   throws StandardException
        Insert a row into the conglomerate.
        Parameters:
        rowToInsert - The row to insert into the conglomerate. The stored representations of the row's columns are copied into a new row somewhere in the conglomerate.
        Returns:
        Returns 0 if insert succeeded. Returns ConglomerateController.ROWISDUPLICATE if conglomerate supports uniqueness checks and has been created to disallow duplicates, and the row inserted had key columns which were duplicate of a row already in the table. Other insert failures will raise StandardException's.
        Throws:
        StandardException - Standard exception policy.
      • close

        public void close()
                   throws StandardException
        Close the conglomerate controller.

        Any changes to this method will probably have to be reflected in close as well.

        Currently delegates to OpenBTree. If the btree controller ends up not having any state of its own, we can remove this method (the VM will dispatch to OpenBTree), gaining some small efficiency. For now, this method remains for clarity.

        Specified by:
        close in interface ConglomerateController
        Overrides:
        close in class OpenBTree
        Throws:
        StandardException - Standard exception policy.
        See Also:
        ConglomerateController.close()
      • closeForEndTransaction

        public boolean closeForEndTransaction​(boolean closeHeldScan)
                                       throws StandardException
        Close conglomerate controller as part of terminating a transaction.

        Use this call to close the conglomerate controller resources as part of committing or aborting a transaction. The normal close() routine may do some cleanup that is either unnecessary, or not correct due to the unknown condition of the controller following a transaction ending error. Use this call when closing all controllers as part of an abort of a transaction.

        This call is meant to only be used internally by the Storage system, clients of the storage system should use the simple close() interface.

        RESOLVE (mikem) - move this call to ConglomerateManager so it is obvious that non-access clients should not call this.

        Specified by:
        closeForEndTransaction in interface ConglomerateController
        Parameters:
        closeHeldScan - If true, means to close controller even if it has been opened to be kept opened across commit. This is used to close these controllers on abort.
        Returns:
        boolean indicating that the close has resulted in a real close of the controller. A held scan will return false if called by closeForEndTransaction(false), otherwise it will return true. A non-held scan will always return true.
        Throws:
        StandardException - Standard exception policy.
      • insert

        public int insert​(DataValueDescriptor[] row)
                   throws StandardException
        Insert a row into the conglomerate.
        Specified by:
        insert in interface ConglomerateController
        Parameters:
        row - The row to insert into the conglomerate. The stored representations of the row's columns are copied into a new row somewhere in the conglomerate.
        Returns:
        Returns 0 if insert succeeded. Returns ConglomerateController.ROWISDUPLICATE if conglomerate supports uniqueness checks and has been created to disallow duplicates, and the row inserted had key columns which were duplicate of a row already in the table. Other insert failures will raise StandardException's.
        Throws:
        StandardException - Standard exception policy.
        See Also:
        ConglomerateController.insert(org.apache.derby.iapi.types.DataValueDescriptor[])
      • getTableProperties

        public void getTableProperties​(java.util.Properties prop)
                                throws StandardException
        Request the system properties associated with a table.

        Request the value of properties that are associated with a table. The following properties can be requested: derby.storage.pageSize derby.storage.pageReservedSpace derby.storage.minimumRecordSize derby.storage.initialPages

        To get the value of a particular property add it to the property list, and on return the value of the property will be set to it's current value. For example: get_prop(ConglomerateController cc) { Properties prop = new Properties(); prop.put("derby.storage.pageSize", ""); cc.getTableProperties(prop); System.out.println( "table's page size = " + prop.getProperty("derby.storage.pageSize"); }

        Specified by:
        getTableProperties in interface ConglomPropertyQueryable
        Parameters:
        prop - Property list to fill in.
        Throws:
        StandardException - Standard exception policy.
      • getInternalTablePropertySet

        public java.util.Properties getInternalTablePropertySet​(java.util.Properties prop)
                                                         throws StandardException
        Request set of properties associated with a table.

        Returns a property object containing all properties that the store knows about, which are stored persistently by the store. This set of properties may vary from implementation to implementation of the store.

        This call is meant to be used only for internal query of the properties by jbms, for instance by language during bulk insert so that it can create a new conglomerate which exactly matches the properties that the original container was created with. This call should not be used by the user interface to present properties to users as it may contain properties that are meant to be internal to jbms. Some properties are meant only to be specified by jbms code and not by users on the command line.

        Note that not all properties passed into createConglomerate() are stored persistently, and that set may vary by store implementation.

        Specified by:
        getInternalTablePropertySet in interface ConglomPropertyQueryable
        Parameters:
        prop - Property list to add properties to. If null, routine will create a new Properties object, fill it in and return it.
        Throws:
        StandardException - Standard exception policy.
      • load

        public long load​(TransactionManager xact_manager,
                         boolean createConglom,
                         RowLocationRetRowSource rowSource)
                  throws StandardException
        Load rows from rowSource into the opened btree.

        Efficiently load rows into the already opened btree. The btree must be table locked, as no row locks will be requested by this routine. On exit from this routine the conglomerate will be closed (on both error or success).

        This routine does an almost bottom up build of a btree. It assumes all rows arrive in sorted order, and inserts them directly into the next (to the right) spot in the current leaf until there is no space. Then it calls the generic split code to add the next leaf (RESOLVE - in the future we could optimize this to split bottom up rather than top down for create index).

        Throws:
        StandardException - Standard exception policy. If conglomerate supports uniqueness checks and has been created to disallow duplicates, and one of the rows being loaded had key columns which were duplicate of a row already in the conglomerate, then raise SQLState.STORE_CONGLOMERATE_DUPLICATE_KEY_EXCEPTION.
        See Also:
        Conglomerate.load(org.apache.derby.iapi.store.access.conglomerate.TransactionManager, boolean, org.apache.derby.iapi.store.access.RowLocationRetRowSource)
      • lockRow

        public boolean lockRow​(RowLocation loc,
                               int lock_operation,
                               boolean wait,
                               int lock_duration)
                        throws StandardException
        Lock the given row location.

        Should only be called by access.

        This call can be made on a ConglomerateController that was opened for locking only.

        RESOLVE (mikem) - move this call to ConglomerateManager so it is obvious that non-access clients should not call this.

        Specified by:
        lockRow in interface ConglomerateController
        Parameters:
        loc - The "RowLocation" which describes the exact row to lock.
        wait - Should the lock call wait to be granted?
        lock_operation - For what operation are we requesting the lock, this should be one of the following 4 options: LOCK_READ [read lock], (LOCK_INS | LOCK_UPD) [ lock for insert], (LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for previous key to insert], (LOCK_UPD) [lock for delete or replace] (LOCK_UPD | LOCK_UPDATE_LOCKS) [lock scan for update, will upgrade lock later if actual update is take place]
        lock_duration - If set to TransactionManager.LOCK_INSTANT_DURATION, then lock will be released immediately after being granted.
        Returns:
        true if lock was granted, only can be false if wait was false.
        Throws:
        StandardException - Standard exception policy.
      • lockRow

        public boolean lockRow​(long page_num,
                               int record_id,
                               int lock_operation,
                               boolean wait,
                               int lock_duration)
                        throws StandardException
        Description copied from interface: ConglomerateController
        Lock the given record id/page num pair.

        Should only be called by access, to lock "special" locks formed from the Recordhandle.* reserved constants for page specific locks.

        This call can be made on a ConglomerateController that was opened for locking only.

        RESOLVE (mikem) - move this call to ConglomerateManager so it is obvious that non-access clients should not call this.

        Specified by:
        lockRow in interface ConglomerateController
        Parameters:
        page_num - page number of record to lock.
        record_id - record id of record to lock.
        lock_operation - For what operation are we requesting the lock, this should be one of the following 4 options: LOCK_READ [read lock], (LOCK_INS | LOCK_UPD) [ lock for insert], (LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for previous key to insert], (LOCK_UPD) [lock for delete or replace] (LOCK_UPD | LOCK_UPDATE_LOCKS) [lock scan for update, will upgrade lock later if actual update is take place]
        wait - Should the lock call wait to be granted?
        lock_duration - If set to TransactionManager.LOCK_INSTANT_DURATION, then lock will be released immediately after being granted.
        Returns:
        true if lock was granted, only can be false if wait was false.
        Throws:
        StandardException - Standard exception policy.
      • unlockRowAfterRead

        public void unlockRowAfterRead​(RowLocation loc,
                                       boolean forUpdate,
                                       boolean row_qualifies)
                                throws StandardException
        Description copied from interface: ConglomerateController
        UnLock the given row location.

        Should only be called by access.

        This call can be made on a ConglomerateController that was opened for locking only.

        RESOLVE (mikem) - move this call to ConglomerateManager so it is obvious that non-access clients should not call this.

        Specified by:
        unlockRowAfterRead in interface ConglomerateController
        Parameters:
        loc - The "RowLocation" which describes the row to unlock.
        forUpdate - Row was locked for read or update.
        row_qualifies - Row was qualified and returned to the user.
        Throws:
        StandardException - Standard exception policy.