Examples with StatisticsDescriptor org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor used on opensource projects

Example 1 with StatisticsDescriptor

use of org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor in project derby by apache.

the class DataDictionaryImpl method getStatisticsDescriptors.

/**
 * Returns all the statistics descriptors for the given table.
 * <p>
 * NOTE: As opposed to most other data dictionary lookups, this operation is
 * performed with isolation level READ_UNCOMMITTED. The reason is to avoid
 * deadlocks with inserts into the statistics system table.
 *
 * @param td {@code TableDescriptor} for which I need statistics
 * @return A list of tuple descriptors, possibly empty.
 */
public List<StatisticsDescriptor> getStatisticsDescriptors(TableDescriptor td) throws StandardException {
    TabInfoImpl ti = getNonCoreTI(SYSSTATISTICS_CATALOG_NUM);
    List<StatisticsDescriptor> statDescriptorList = newSList();
    DataValueDescriptor UUIDStringOrderable;
    /* set up the start/stop position for the scan */
    UUIDStringOrderable = getIDValueAsCHAR(td.getUUID());
    ExecIndexRow keyRow = exFactory.getIndexableRow(1);
    keyRow.setColumn(1, UUIDStringOrderable);
    getDescriptorViaIndex(SYSSTATISTICSRowFactory.SYSSTATISTICS_INDEX1_ID, keyRow, (ScanQualifier[][]) null, ti, (TupleDescriptor) null, statDescriptorList, StatisticsDescriptor.class, false, TransactionController.ISOLATION_READ_UNCOMMITTED, getTransactionCompile());
    return statDescriptorList;
}

Example 2 with StatisticsDescriptor

use of org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor in project derby by apache.

the class SYSSTATISTICSRowFactory method buildDescriptor.

public TupleDescriptor buildDescriptor(ExecRow row, TupleDescriptor parentDesc, DataDictionary dd) throws StandardException {
    if (SanityManager.DEBUG) {
        SanityManager.ASSERT(row.nColumns() == SYSSTATISTICS_COLUMN_COUNT, "Wrong number of columns for a SYSSTATISTICS row");
    }
    DataValueDescriptor col;
    String scratch;
    UUIDFactory uuidFactory = getUUIDFactory();
    UUID statUUID, statReferenceUUID, statTableUUID;
    String statName;
    /* 1st column is UUID */
    col = row.getColumn(SYSSTATISTICS_ID);
    scratch = col.getString();
    statUUID = uuidFactory.recreateUUID(scratch);
    /* 2nd column is reference UUID */
    col = row.getColumn(SYSSTATISTICS_REFERENCEID);
    scratch = col.getString();
    statReferenceUUID = uuidFactory.recreateUUID(scratch);
    /* 3rd column is table UUID */
    col = row.getColumn(SYSSTATISTICS_TABLEID);
    scratch = col.getString();
    statTableUUID = uuidFactory.recreateUUID(scratch);
    /* 4th column is timestamp */
    col = row.getColumn(SYSSTATISTICS_TIMESTAMP);
    Timestamp updateTime = (Timestamp) col.getObject();
    /* 5th column is stat type -- string */
    col = row.getColumn(SYSSTATISTICS_TYPE);
    String statType = col.getString();
    /* 6th column is stat valid -- boolean */
    col = row.getColumn(SYSSTATISTICS_VALID);
    boolean valid = col.getBoolean();
    /* 7th column is column count */
    col = row.getColumn(SYSSTATISTICS_COLCOUNT);
    int columnCount = col.getInt();
    /* 8th column is statistics itself */
    col = row.getColumn(SYSSTATISTICS_STAT);
    Statistics stat = (Statistics) col.getObject();
    return new StatisticsDescriptor(dd, statUUID, statReferenceUUID, // statName, colMap,
    statTableUUID, statType, stat, columnCount);
}

Example 3 with StatisticsDescriptor

use of org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor in project derby by apache.

the class IndexStatisticsDaemonImpl method updateIndexStatsMinion.

/**
 * Updates the index statistics for the given table and the specified
 * indexes.
 * <p>
 * <strong>API note</strong>: Using {@code null} to update the statistics
 * for all conglomerates is preferred over explicitly passing an array with
 * all the conglomerates for the table. Doing so allows for some
 * optimizations, and will cause a disposable statistics check to be
 * performed.
 *
 * @param lcc language connection context used to perform the work
 * @param td the table to update index stats for
 * @param cds the conglomerates to update statistics for (non-index
 *      conglomerates will be ignored), {@code null} means all indexes
 * @param asBackgroundTask whether the updates are done automatically as
 *      part of a background task or if explicitly invoked by the user
 * @throws StandardException if something goes wrong
 */
private void updateIndexStatsMinion(LanguageConnectionContext lcc, TableDescriptor td, ConglomerateDescriptor[] cds, boolean asBackgroundTask) throws StandardException {
    // can only properly identify disposable stats if cds == null,
    // which means we are processing all indexes on the conglomerate.
    final boolean identifyDisposableStats = (cds == null);
    // Fetch descriptors if we're updating statistics for all indexes.
    if (cds == null) {
        cds = td.getConglomerateDescriptors();
    }
    // Extract/derive information from the table descriptor
    long[] conglomerateNumber = new long[cds.length];
    ExecIndexRow[] indexRow = new ExecIndexRow[cds.length];
    TransactionController tc = lcc.getTransactionExecute();
    ConglomerateController heapCC = tc.openConglomerate(td.getHeapConglomerateId(), false, 0, TransactionController.MODE_RECORD, asBackgroundTask ? TransactionController.ISOLATION_READ_UNCOMMITTED : TransactionController.ISOLATION_REPEATABLE_READ);
    // create a list of indexes that should have statistics, by looking
    // at all indexes on the conglomerate, and conditionally skipping
    // unique single column indexes.  This set is the "non disposable
    // stat list".
    UUID[] non_disposable_objectUUID = new UUID[cds.length];
    try {
        for (int i = 0; i < cds.length; i++) {
            // Skip non-index conglomerates
            if (!cds[i].isIndex()) {
                conglomerateNumber[i] = -1;
                continue;
            }
            IndexRowGenerator irg = cds[i].getIndexDescriptor();
            // or we are running in soft-upgrade-mode on a pre 10.9 db.
            if (skipDisposableStats) {
                if (irg.isUnique() && irg.numberOfOrderedColumns() == 1) {
                    conglomerateNumber[i] = -1;
                    continue;
                }
            }
            // at this point have found a stat for an existing
            // index which is not a single column unique index, add it
            // to the list of "non disposable stats"
            conglomerateNumber[i] = cds[i].getConglomerateNumber();
            non_disposable_objectUUID[i] = cds[i].getUUID();
            indexRow[i] = irg.getNullIndexRow(td.getColumnDescriptorList(), heapCC.newRowLocationTemplate());
        }
    } finally {
        heapCC.close();
    }
    if (identifyDisposableStats) {
        // Note this loop is not controlled by the skipDisposableStats
        // flag.  The above loop controls if we drop single column unique
        // index stats or not.  In all cases we are going to drop
        // stats with no associated index (orphaned stats).
        List<StatisticsDescriptor> existingStats = td.getStatistics();
        StatisticsDescriptor[] stats = (StatisticsDescriptor[]) existingStats.toArray(new StatisticsDescriptor[existingStats.size()]);
        // those entries that don't have a matching conglomerate in the
        for (int si = 0; si < stats.length; si++) {
            UUID referencedIndex = stats[si].getReferenceID();
            boolean isValid = false;
            for (int ci = 0; ci < conglomerateNumber.length; ci++) {
                if (referencedIndex.equals(non_disposable_objectUUID[ci])) {
                    isValid = true;
                    break;
                }
            }
            // mechanism in case of another bug like DERBY-5681 in Derby.
            if (!isValid) {
                String msg = "dropping disposable statistics entry " + stats[si].getUUID() + " for index " + stats[si].getReferenceID() + " (cols=" + stats[si].getColumnCount() + ")";
                logAlways(td, null, msg);
                trace(1, msg + " on table " + stats[si].getTableUUID());
                DataDictionary dd = lcc.getDataDictionary();
                if (!lcc.dataDictionaryInWriteMode()) {
                    dd.startWriting(lcc);
                }
                dd.dropStatisticsDescriptors(td.getUUID(), stats[si].getReferenceID(), tc);
                if (asBackgroundTask) {
                    lcc.internalCommit(true);
                }
            }
        }
    }
    // [x][0] = conglomerate number, [x][1] = start time, [x][2] = stop time
    long[][] scanTimes = new long[conglomerateNumber.length][3];
    int sci = 0;
    for (int indexNumber = 0; indexNumber < conglomerateNumber.length; indexNumber++) {
        if (conglomerateNumber[indexNumber] == -1)
            continue;
        // Check if daemon has been disabled.
        if (asBackgroundTask) {
            if (isShuttingDown()) {
                break;
            }
        }
        scanTimes[sci][0] = conglomerateNumber[indexNumber];
        scanTimes[sci][1] = System.currentTimeMillis();
        // Subtract one for the RowLocation added for indexes.
        int numCols = indexRow[indexNumber].nColumns() - 1;
        long[] cardinality = new long[numCols];
        KeyComparator cmp = new KeyComparator(indexRow[indexNumber]);
        /* Read uncommitted, with record locking. Actually CS store may
               not hold record locks */
        GroupFetchScanController gsc = tc.openGroupFetchScan(conglomerateNumber[indexNumber], // hold
        false, 0, // locking
        TransactionController.MODE_RECORD, TransactionController.ISOLATION_READ_UNCOMMITTED, // scancolumnlist-- want everything.
        null, // startkeyvalue-- start from the beginning.
        null, 0, // qualifiers, none!
        null, // stopkeyvalue,
        null, 0);
        try {
            int rowsFetched = 0;
            boolean giving_up_on_shutdown = false;
            while ((rowsFetched = cmp.fetchRows(gsc)) > 0) {
                // I/O that is processed as a convenient point.
                if (asBackgroundTask) {
                    if (isShuttingDown()) {
                        giving_up_on_shutdown = true;
                        break;
                    }
                }
                for (int i = 0; i < rowsFetched; i++) {
                    int whichPositionChanged = cmp.compareWithPrevKey(i);
                    if (whichPositionChanged >= 0) {
                        for (int j = whichPositionChanged; j < numCols; j++) cardinality[j]++;
                    }
                }
            }
            if (giving_up_on_shutdown)
                break;
            gsc.setEstimatedRowCount(cmp.getRowCount());
        } finally // try
        {
            gsc.close();
            gsc = null;
        }
        scanTimes[sci++][2] = System.currentTimeMillis();
        // We have scanned the indexes, so let's give this a few attempts
        // before giving up.
        int retries = 0;
        while (true) {
            try {
                writeUpdatedStats(lcc, td, non_disposable_objectUUID[indexNumber], cmp.getRowCount(), cardinality, asBackgroundTask);
                break;
            } catch (StandardException se) {
                retries++;
                if (se.isLockTimeout() && retries < 3) {
                    trace(2, "lock timeout when writing stats, retrying");
                    sleep(100 * retries);
                } else {
                    // o too many lock timeouts
                    throw se;
                }
            }
        }
    }
    log(asBackgroundTask, td, fmtScanTimes(scanTimes));
}

Example 4 with StatisticsDescriptor

use of org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor in project derby by apache.

the class AlterTableConstantAction method updateIndex.

private void updateIndex(long newHeapConglom, DataDictionary dd, int index, long[] newIndexCongloms) throws StandardException {
    Properties properties = new Properties();
    // Get the ConglomerateDescriptor for the index
    ConglomerateDescriptor cd = td.getConglomerateDescriptor(indexConglomerateNumbers[index]);
    // Build the properties list for the new conglomerate
    ConglomerateController indexCC = tc.openConglomerate(indexConglomerateNumbers[index], false, TransactionController.OPENMODE_FORUPDATE, TransactionController.MODE_TABLE, TransactionController.ISOLATION_SERIALIZABLE);
    // Get the properties on the old index
    indexCC.getInternalTablePropertySet(properties);
    /* Create the properties that language supplies when creating the
		 * the index.  (The store doesn't preserve these.)
		 */
    int indexRowLength = indexRows[index].nColumns();
    properties.put("baseConglomerateId", Long.toString(newHeapConglom));
    if (cd.getIndexDescriptor().isUnique()) {
        properties.put("nUniqueColumns", Integer.toString(indexRowLength - 1));
    } else {
        properties.put("nUniqueColumns", Integer.toString(indexRowLength));
    }
    if (cd.getIndexDescriptor().isUniqueWithDuplicateNulls() && !cd.getIndexDescriptor().hasDeferrableChecking()) {
        properties.put("uniqueWithDuplicateNulls", Boolean.toString(true));
    }
    properties.put("rowLocationColumn", Integer.toString(indexRowLength - 1));
    properties.put("nKeyFields", Integer.toString(indexRowLength));
    indexCC.close();
    // We can finally drain the sorter and rebuild the index
    // Populate the index.
    RowLocationRetRowSource cCount;
    boolean statisticsExist = false;
    if (!truncateTable) {
        sorters[index].completedInserts();
        sorters[index] = null;
        if (td.statisticsExist(cd)) {
            cCount = new CardinalityCounter(tc.openSortRowSource(sortIds[index]));
            statisticsExist = true;
        } else {
            cCount = new CardinalityCounter(tc.openSortRowSource(sortIds[index]));
        }
        newIndexCongloms[index] = tc.createAndLoadConglomerate("BTREE", indexRows[index].getRowArray(), ordering[index], collation[index], properties, TransactionController.IS_DEFAULT, cCount, (long[]) null);
        // is not empty.
        if (statisticsExist)
            dd.dropStatisticsDescriptors(td.getUUID(), cd.getUUID(), tc);
        long numRows;
        if ((numRows = ((CardinalityCounter) cCount).getRowCount()) > 0) {
            long[] c = ((CardinalityCounter) cCount).getCardinality();
            for (int i = 0; i < c.length; i++) {
                StatisticsDescriptor statDesc = new StatisticsDescriptor(dd, dd.getUUIDFactory().createUUID(), cd.getUUID(), td.getUUID(), "I", new StatisticsImpl(numRows, c[i]), i + 1);
                dd.addDescriptor(statDesc, // no parent descriptor
                null, DataDictionary.SYSSTATISTICS_CATALOG_NUM, // no error on duplicate.
                true, tc);
            }
        }
    } else {
        newIndexCongloms[index] = tc.createConglomerate("BTREE", indexRows[index].getRowArray(), ordering[index], collation[index], properties, TransactionController.IS_DEFAULT);
        // rowscount is zero and existing statistic will be invalid.
        if (td.statisticsExist(cd))
            dd.dropStatisticsDescriptors(td.getUUID(), cd.getUUID(), tc);
    }
    /* Update the DataDictionary
		 *
		 * Update sys.sysconglomerates with new conglomerate #, we need to
		 * update all (if any) duplicate index entries sharing this same
		 * conglomerate.
		 */
    dd.updateConglomerateDescriptor(td.getConglomerateDescriptors(indexConglomerateNumbers[index]), newIndexCongloms[index], tc);
    // Drop the old conglomerate
    tc.dropConglomerate(indexConglomerateNumbers[index]);
}

Example 5 with StatisticsDescriptor

use of org.apache.derby.iapi.sql.dictionary.StatisticsDescriptor in project derby by apache.

the class CreateIndexConstantAction method executeConstantAction.

// INTERFACE METHODS
/**
 *	This is the guts of the Execution-time logic for
 *  creating an index.
 *
 *  <P>
 *  A index is represented as:
 *  <UL>
 *  <LI> ConglomerateDescriptor.
 *  </UL>
 *  No dependencies are created.
 *
 *  @see ConglomerateDescriptor
 *  @see SchemaDescriptor
 *	@see ConstantAction#executeConstantAction
 *
 * @exception StandardException		Thrown on failure
 */
public void executeConstantAction(Activation activation) throws StandardException {
    TableDescriptor td;
    UUID toid;
    ColumnDescriptor columnDescriptor;
    int[] baseColumnPositions;
    IndexRowGenerator indexRowGenerator = null;
    ExecRow[] baseRows;
    ExecIndexRow[] indexRows;
    ExecRow[] compactBaseRows;
    GroupFetchScanController scan;
    RowLocationRetRowSource rowSource;
    long sortId;
    int maxBaseColumnPosition = -1;
    LanguageConnectionContext lcc = activation.getLanguageConnectionContext();
    DataDictionary dd = lcc.getDataDictionary();
    DependencyManager dm = dd.getDependencyManager();
    TransactionController tc = lcc.getTransactionExecute();
    /*
		** Inform the data dictionary that we are about to write to it.
		** There are several calls to data dictionary "get" methods here
		** that might be done in "read" mode in the data dictionary, but
		** it seemed safer to do this whole operation in "write" mode.
		**
		** We tell the data dictionary we're done writing at the end of
		** the transaction.
		*/
    dd.startWriting(lcc);
    /*
		** If the schema descriptor is null, then
		** we must have just read ourselves in.  
		** So we will get the corresponding schema
		** descriptor from the data dictionary.
		*/
    SchemaDescriptor sd = dd.getSchemaDescriptor(schemaName, tc, true);
    /* Get the table descriptor. */
    /* See if we can get the TableDescriptor 
		 * from the Activation.  (Will be there
		 * for backing indexes.)
		 */
    td = activation.getDDLTableDescriptor();
    if (td == null) {
        /* tableId will be non-null if adding an index to
			 * an existing table (as opposed to creating a
			 * table with a constraint with a backing index).
			 */
        if (tableId != null) {
            td = dd.getTableDescriptor(tableId);
        } else {
            td = dd.getTableDescriptor(tableName, sd, tc);
        }
    }
    if (td == null) {
        throw StandardException.newException(SQLState.LANG_CREATE_INDEX_NO_TABLE, indexName, tableName);
    }
    if (td.getTableType() == TableDescriptor.SYSTEM_TABLE_TYPE) {
        throw StandardException.newException(SQLState.LANG_CREATE_SYSTEM_INDEX_ATTEMPTED, indexName, tableName);
    }
    /* Get a shared table lock on the table. We need to lock table before
		 * invalidate dependents, otherwise, we may interfere with the
		 * compilation/re-compilation of DML/DDL.  See beetle 4325 and $WS/
		 * docs/language/SolutionsToConcurrencyIssues.txt (point f).
		 */
    lockTableForDDL(tc, td.getHeapConglomerateId(), false);
    // depended on this table (including this one)
    if (!forCreateTable) {
        dm.invalidateFor(td, DependencyManager.CREATE_INDEX, lcc);
    }
    // Translate the base column names to column positions
    baseColumnPositions = new int[columnNames.length];
    for (int i = 0; i < columnNames.length; i++) {
        // Look up the column in the data dictionary
        columnDescriptor = td.getColumnDescriptor(columnNames[i]);
        if (columnDescriptor == null) {
            throw StandardException.newException(SQLState.LANG_COLUMN_NOT_FOUND_IN_TABLE, columnNames[i], tableName);
        }
        TypeId typeId = columnDescriptor.getType().getTypeId();
        // Don't allow a column to be created on a non-orderable type
        ClassFactory cf = lcc.getLanguageConnectionFactory().getClassFactory();
        boolean isIndexable = typeId.orderable(cf);
        if (isIndexable && typeId.userType()) {
            String userClass = typeId.getCorrespondingJavaTypeName();
            // run the compare method.
            try {
                if (cf.isApplicationClass(cf.loadApplicationClass(userClass)))
                    isIndexable = false;
            } catch (ClassNotFoundException cnfe) {
                // shouldn't happen as we just check the class is orderable
                isIndexable = false;
            }
        }
        if (!isIndexable) {
            throw StandardException.newException(SQLState.LANG_COLUMN_NOT_ORDERABLE_DURING_EXECUTION, typeId.getSQLTypeName());
        }
        // Remember the position in the base table of each column
        baseColumnPositions[i] = columnDescriptor.getPosition();
        if (maxBaseColumnPosition < baseColumnPositions[i])
            maxBaseColumnPosition = baseColumnPositions[i];
    }
    /* The code below tries to determine if the index that we're about
		 * to create can "share" a conglomerate with an existing index.
		 * If so, we will use a single physical conglomerate--namely, the
		 * one that already exists--to support both indexes. I.e. we will
		 * *not* create a new conglomerate as part of this constant action.
         *
         * Deferrable constraints are backed by indexes that are *not* shared
         * since they use physically non-unique indexes and as such are
         * different from indexes used to represent non-deferrable
         * constraints.
		 */
    // check if we have similar indices already for this table
    ConglomerateDescriptor[] congDescs = td.getConglomerateDescriptors();
    boolean shareExisting = false;
    for (int i = 0; i < congDescs.length; i++) {
        ConglomerateDescriptor cd = congDescs[i];
        if (!cd.isIndex())
            continue;
        if (droppedConglomNum == cd.getConglomerateNumber()) {
            /* We can't share with any conglomerate descriptor
				 * whose conglomerate number matches the dropped
				 * conglomerate number, because that descriptor's
				 * backing conglomerate was dropped, as well.  If
				 * we're going to share, we have to share with a
				 * descriptor whose backing physical conglomerate
				 * is still around.
				 */
            continue;
        }
        IndexRowGenerator irg = cd.getIndexDescriptor();
        int[] bcps = irg.baseColumnPositions();
        boolean[] ia = irg.isAscending();
        int j = 0;
        /* The conditions which allow an index to share an existing
			 * conglomerate are as follows:
			 *
			 * 1. the set of columns (both key and include columns) and their 
			 *  order in the index is the same as that of an existing index AND 
			 *
			 * 2. the ordering attributes are the same AND 
			 *
			 * 3. one of the following is true:
			 *    a) the existing index is unique, OR
			 *    b) the existing index is non-unique with uniqueWhenNotNulls
			 *       set to TRUE and the index being created is non-unique, OR
			 *    c) both the existing index and the one being created are
			 *       non-unique and have uniqueWithDuplicateNulls set to FALSE.
             *
             * 4. hasDeferrableChecking is FALSE.
             */
        boolean possibleShare = (irg.isUnique() || !unique) && (bcps.length == baseColumnPositions.length) && !hasDeferrableChecking;
        // is set to true (backing index for unique constraint)
        if (possibleShare && !irg.isUnique()) {
            /* If the existing index has uniqueWithDuplicateNulls set to
				 * TRUE it can be shared by other non-unique indexes; otherwise
				 * the existing non-unique index has uniqueWithDuplicateNulls
				 * set to FALSE, which means the new non-unique conglomerate
				 * can only share if it has uniqueWithDuplicateNulls set to
				 * FALSE, as well.
				 */
            possibleShare = (irg.isUniqueWithDuplicateNulls() || !uniqueWithDuplicateNulls);
        }
        if (possibleShare && indexType.equals(irg.indexType())) {
            for (; j < bcps.length; j++) {
                if ((bcps[j] != baseColumnPositions[j]) || (ia[j] != isAscending[j]))
                    break;
            }
        }
        if (// share
        j == baseColumnPositions.length) {
            /*
				 * Don't allow users to create a duplicate index. Allow if being done internally
				 * for a constraint
				 */
            if (!isConstraint) {
                activation.addWarning(StandardException.newWarning(SQLState.LANG_INDEX_DUPLICATE, indexName, cd.getConglomerateName()));
                return;
            }
            /* Sharing indexes share the physical conglomerate
				 * underneath, so pull the conglomerate number from
				 * the existing conglomerate descriptor.
				 */
            conglomId = cd.getConglomerateNumber();
            /* We create a new IndexRowGenerator because certain
				 * attributes--esp. uniqueness--may be different between
				 * the index we're creating and the conglomerate that
				 * already exists.  I.e. even though we're sharing a
				 * conglomerate, the new index is not necessarily
				 * identical to the existing conglomerate. We have to
				 * keep track of that info so that if we later drop
				 * the shared physical conglomerate, we can figure out
				 * what this index (the one we're creating now) is
				 * really supposed to look like.
				 */
            indexRowGenerator = new IndexRowGenerator(indexType, unique, uniqueWithDuplicateNulls, // uniqueDeferrable
            false, // deferrable indexes are not shared
            false, baseColumnPositions, isAscending, baseColumnPositions.length);
            // DERBY-655 and DERBY-1343
            // Sharing indexes will have unique logical conglomerate UUIDs.
            conglomerateUUID = dd.getUUIDFactory().createUUID();
            shareExisting = true;
            break;
        }
    }
    /* If we have a droppedConglomNum then the index we're about to
		 * "create" already exists--i.e. it has an index descriptor and
		 * the corresponding information is already in the system catalogs.
		 * The only thing we're missing, then, is the physical conglomerate
		 * to back the index (because the old conglomerate was dropped).
		 */
    boolean alreadyHaveConglomDescriptor = (droppedConglomNum > -1L);
    /* If this index already has an essentially same one, we share the
		 * conglomerate with the old one, and just simply add a descriptor
		 * entry into SYSCONGLOMERATES--unless we already have a descriptor,
		 * in which case we don't even need to do that.
		 */
    DataDescriptorGenerator ddg = dd.getDataDescriptorGenerator();
    if (shareExisting && !alreadyHaveConglomDescriptor) {
        ConglomerateDescriptor cgd = ddg.newConglomerateDescriptor(conglomId, indexName, true, indexRowGenerator, isConstraint, conglomerateUUID, td.getUUID(), sd.getUUID());
        dd.addDescriptor(cgd, sd, DataDictionary.SYSCONGLOMERATES_CATALOG_NUM, false, tc);
        // add newly added conglomerate to the list of conglomerate
        // descriptors in the td.
        ConglomerateDescriptorList cdl = td.getConglomerateDescriptorList();
        cdl.add(cgd);
    // can't just return yet, need to get member "indexTemplateRow"
    // because create constraint may use it
    }
    // Describe the properties of the index to the store using Properties
    // RESOLVE: The following properties assume a BTREE index.
    Properties indexProperties;
    if (properties != null) {
        indexProperties = properties;
    } else {
        indexProperties = new Properties();
    }
    // Tell it the conglomerate id of the base table
    indexProperties.put("baseConglomerateId", Long.toString(td.getHeapConglomerateId()));
    if (uniqueWithDuplicateNulls && !hasDeferrableChecking) {
        if (dd.checkVersion(DataDictionary.DD_VERSION_DERBY_10_4, null)) {
            indexProperties.put("uniqueWithDuplicateNulls", Boolean.toString(true));
        } else {
            // index creating a unique index instead.
            if (uniqueWithDuplicateNulls) {
                unique = true;
            }
        }
    }
    // All indexes are unique because they contain the RowLocation.
    // The number of uniqueness columns must include the RowLocation
    // if the user did not specify a unique index.
    indexProperties.put("nUniqueColumns", Integer.toString(unique ? baseColumnPositions.length : baseColumnPositions.length + 1));
    // By convention, the row location column is the last column
    indexProperties.put("rowLocationColumn", Integer.toString(baseColumnPositions.length));
    // For now, all columns are key fields, including the RowLocation
    indexProperties.put("nKeyFields", Integer.toString(baseColumnPositions.length + 1));
    // For now, assume that all index columns are ordered columns
    if (!shareExisting) {
        if (dd.checkVersion(DataDictionary.DD_VERSION_DERBY_10_4, null)) {
            indexRowGenerator = new IndexRowGenerator(indexType, unique, uniqueWithDuplicateNulls, uniqueDeferrable, (hasDeferrableChecking && constraintType != DataDictionary.FOREIGNKEY_CONSTRAINT), baseColumnPositions, isAscending, baseColumnPositions.length);
        } else {
            indexRowGenerator = new IndexRowGenerator(indexType, unique, false, false, false, baseColumnPositions, isAscending, baseColumnPositions.length);
        }
    }
    /* Now add the rows from the base table to the conglomerate.
		 * We do this by scanning the base table and inserting the
		 * rows into a sorter before inserting from the sorter
		 * into the index.  This gives us better performance
		 * and a more compact index.
		 */
    rowSource = null;
    sortId = 0;
    // set to true once the sorter is created
    boolean needToDropSort = false;
    /* bulkFetchSIze will be 16 (for now) unless
		 * we are creating the table in which case it
		 * will be 1.  Too hard to remove scan when
		 * creating index on new table, so minimize
		 * work where we can.
		 */
    int bulkFetchSize = (forCreateTable) ? 1 : 16;
    int numColumns = td.getNumberOfColumns();
    int approximateRowSize = 0;
    // Create the FormatableBitSet for mapping the partial to full base row
    FormatableBitSet bitSet = new FormatableBitSet(numColumns + 1);
    for (int index = 0; index < baseColumnPositions.length; index++) {
        bitSet.set(baseColumnPositions[index]);
    }
    FormatableBitSet zeroBasedBitSet = RowUtil.shift(bitSet, 1);
    // Start by opening a full scan on the base table.
    scan = tc.openGroupFetchScan(td.getHeapConglomerateId(), // hold
    false, // open base table read only
    0, TransactionController.MODE_TABLE, TransactionController.ISOLATION_SERIALIZABLE, // all fields as objects
    zeroBasedBitSet, // startKeyValue
    (DataValueDescriptor[]) null, // not used when giving null start posn.
    0, // qualifier
    null, // stopKeyValue
    (DataValueDescriptor[]) null, // not used when giving null stop posn.
    0);
    // Create an array to put base row template
    baseRows = new ExecRow[bulkFetchSize];
    indexRows = new ExecIndexRow[bulkFetchSize];
    compactBaseRows = new ExecRow[bulkFetchSize];
    try {
        // Create the array of base row template
        for (int i = 0; i < bulkFetchSize; i++) {
            // create a base row template
            baseRows[i] = activation.getExecutionFactory().getValueRow(maxBaseColumnPosition);
            // create an index row template
            indexRows[i] = indexRowGenerator.getIndexRowTemplate();
            // create a compact base row template
            compactBaseRows[i] = activation.getExecutionFactory().getValueRow(baseColumnPositions.length);
        }
        indexTemplateRow = indexRows[0];
        // Fill the partial row with nulls of the correct type
        ColumnDescriptorList cdl = td.getColumnDescriptorList();
        int cdlSize = cdl.size();
        for (int index = 0, numSet = 0; index < cdlSize; index++) {
            if (!zeroBasedBitSet.get(index)) {
                continue;
            }
            numSet++;
            ColumnDescriptor cd = cdl.elementAt(index);
            DataTypeDescriptor dts = cd.getType();
            for (int i = 0; i < bulkFetchSize; i++) {
                // Put the column in both the compact and sparse base rows
                baseRows[i].setColumn(index + 1, dts.getNull());
                compactBaseRows[i].setColumn(numSet, baseRows[i].getColumn(index + 1));
            }
            // Calculate the approximate row size for the index row
            approximateRowSize += dts.getTypeId().getApproximateLengthInBytes(dts);
        }
        // Get an array of RowLocation template
        RowLocation[] rl = new RowLocation[bulkFetchSize];
        for (int i = 0; i < bulkFetchSize; i++) {
            rl[i] = scan.newRowLocationTemplate();
            // Get an index row based on the base row
            indexRowGenerator.getIndexRow(compactBaseRows[i], rl[i], indexRows[i], bitSet);
        }
        /* now that we got indexTemplateRow, done for sharing index
			 */
        if (shareExisting)
            return;
        /* For non-unique indexes, we order by all columns + the RID.
			 * For unique indexes, we just order by the columns.
			 * We create a unique index observer for unique indexes
			 * so that we can catch duplicate key.
			 * We create a basic sort observer for non-unique indexes
			 * so that we can reuse the wrappers during an external
			 * sort.
			 */
        int numColumnOrderings;
        SortObserver sortObserver;
        Properties sortProperties = null;
        if (unique || uniqueWithDuplicateNulls || uniqueDeferrable) {
            // if the index is a constraint, use constraintname in
            // possible error message
            String indexOrConstraintName = indexName;
            if (conglomerateUUID != null) {
                ConglomerateDescriptor cd = dd.getConglomerateDescriptor(conglomerateUUID);
                if ((isConstraint) && (cd != null && cd.getUUID() != null && td != null)) {
                    ConstraintDescriptor conDesc = dd.getConstraintDescriptor(td, cd.getUUID());
                    indexOrConstraintName = conDesc.getConstraintName();
                }
            }
            if (unique || uniqueDeferrable) {
                numColumnOrderings = unique ? baseColumnPositions.length : baseColumnPositions.length + 1;
                sortObserver = new UniqueIndexSortObserver(lcc, constraintID, true, uniqueDeferrable, initiallyDeferred, indexOrConstraintName, indexTemplateRow, true, td.getName());
            } else {
                // unique with duplicate nulls allowed.
                numColumnOrderings = baseColumnPositions.length + 1;
                // tell transaction controller to use the unique with
                // duplicate nulls sorter, when making createSort() call.
                sortProperties = new Properties();
                sortProperties.put(AccessFactoryGlobals.IMPL_TYPE, AccessFactoryGlobals.SORT_UNIQUEWITHDUPLICATENULLS_EXTERNAL);
                // use sort operator which treats nulls unequal
                sortObserver = new UniqueWithDuplicateNullsIndexSortObserver(lcc, constraintID, true, (hasDeferrableChecking && constraintType != DataDictionary.FOREIGNKEY_CONSTRAINT), initiallyDeferred, indexOrConstraintName, indexTemplateRow, true, td.getName());
            }
        } else {
            numColumnOrderings = baseColumnPositions.length + 1;
            sortObserver = new BasicSortObserver(true, false, indexTemplateRow, true);
        }
        ColumnOrdering[] order = new ColumnOrdering[numColumnOrderings];
        for (int i = 0; i < numColumnOrderings; i++) {
            order[i] = new IndexColumnOrder(i, unique || i < numColumnOrderings - 1 ? isAscending[i] : true);
        }
        // create the sorter
        sortId = tc.createSort(sortProperties, indexTemplateRow.getRowArrayClone(), order, sortObserver, // not in order
        false, scan.getEstimatedRowCount(), // est row size, -1 means no idea
        approximateRowSize);
        needToDropSort = true;
        // Populate sorter and get the output of the sorter into a row
        // source.  The sorter has the indexed columns only and the columns
        // are in the correct order.
        rowSource = loadSorter(baseRows, indexRows, tc, scan, sortId, rl);
        conglomId = tc.createAndLoadConglomerate(indexType, // index row template
        indexTemplateRow.getRowArray(), // colums sort order
        order, indexRowGenerator.getColumnCollationIds(td.getColumnDescriptorList()), indexProperties, // not temporary
        TransactionController.IS_DEFAULT, rowSource, (long[]) null);
    } finally {
        /* close the table scan */
        if (scan != null)
            scan.close();
        /* close the sorter row source before throwing exception */
        if (rowSource != null)
            rowSource.closeRowSource();
        /*
			** drop the sort so that intermediate external sort run can be
			** removed from disk
			*/
        if (needToDropSort)
            tc.dropSort(sortId);
    }
    ConglomerateController indexController = tc.openConglomerate(conglomId, false, 0, TransactionController.MODE_TABLE, TransactionController.ISOLATION_SERIALIZABLE);
    // Check to make sure that the conglomerate can be used as an index
    if (!indexController.isKeyed()) {
        indexController.close();
        throw StandardException.newException(SQLState.LANG_NON_KEYED_INDEX, indexName, indexType);
    }
    indexController.close();
    // 
    if (!alreadyHaveConglomDescriptor) {
        ConglomerateDescriptor cgd = ddg.newConglomerateDescriptor(conglomId, indexName, true, indexRowGenerator, isConstraint, conglomerateUUID, td.getUUID(), sd.getUUID());
        dd.addDescriptor(cgd, sd, DataDictionary.SYSCONGLOMERATES_CATALOG_NUM, false, tc);
        // add newly added conglomerate to the list of conglomerate
        // descriptors in the td.
        ConglomerateDescriptorList cdl = td.getConglomerateDescriptorList();
        cdl.add(cgd);
        /* Since we created a new conglomerate descriptor, load
			 * its UUID into the corresponding field, to ensure that
			 * it is properly set in the StatisticsDescriptor created
			 * below.
			 */
        conglomerateUUID = cgd.getUUID();
    }
    CardinalityCounter cCount = (CardinalityCounter) rowSource;
    long numRows = cCount.getRowCount();
    if (addStatistics(dd, indexRowGenerator, numRows)) {
        long[] c = cCount.getCardinality();
        for (int i = 0; i < c.length; i++) {
            StatisticsDescriptor statDesc = new StatisticsDescriptor(dd, dd.getUUIDFactory().createUUID(), conglomerateUUID, td.getUUID(), "I", new StatisticsImpl(numRows, c[i]), i + 1);
            dd.addDescriptor(statDesc, null, DataDictionary.SYSSTATISTICS_CATALOG_NUM, true, tc);
        }
    }
}