Examples with Cursor org.h2.mvstore.Cursor used on opensource projects

Example 11 with Cursor

use of org.h2.mvstore.Cursor in project h2database by h2database.

the class IndexCursor method prepare.

/**
 * Prepare this index cursor to make a lookup in index.
 *
 * @param s Session.
 * @param indexConditions Index conditions.
 */
public void prepare(Session s, ArrayList<IndexCondition> indexConditions) {
    this.session = s;
    alwaysFalse = false;
    start = end = null;
    inList = null;
    inColumn = null;
    inResult = null;
    inResultTested = null;
    intersects = null;
    // don't use enhanced for loop to avoid creating objects
    for (IndexCondition condition : indexConditions) {
        if (condition.isAlwaysFalse()) {
            alwaysFalse = true;
            break;
        }
        // lookups, each such lookup will perform an own table scan.
        if (index.isFindUsingFullTableScan()) {
            continue;
        }
        Column column = condition.getColumn();
        if (condition.getCompareType() == Comparison.IN_LIST) {
            if (start == null && end == null) {
                if (canUseIndexForIn(column)) {
                    this.inColumn = column;
                    inList = condition.getCurrentValueList(s);
                    inListIndex = 0;
                }
            }
        } else if (condition.getCompareType() == Comparison.IN_QUERY) {
            if (start == null && end == null) {
                if (canUseIndexForIn(column)) {
                    this.inColumn = column;
                    inResult = condition.getCurrentResult();
                }
            }
        } else {
            Value v = condition.getCurrentValue(s);
            boolean isStart = condition.isStart();
            boolean isEnd = condition.isEnd();
            boolean isIntersects = condition.isSpatialIntersects();
            int columnId = column.getColumnId();
            if (columnId >= 0) {
                IndexColumn idxCol = indexColumns[columnId];
                if (idxCol != null && (idxCol.sortType & SortOrder.DESCENDING) != 0) {
                    // if the index column is sorted the other way, we swap
                    // end and start NULLS_FIRST / NULLS_LAST is not a
                    // problem, as nulls never match anyway
                    boolean temp = isStart;
                    isStart = isEnd;
                    isEnd = temp;
                }
            }
            if (isStart) {
                start = getSearchRow(start, columnId, v, true);
            }
            if (isEnd) {
                end = getSearchRow(end, columnId, v, false);
            }
            if (isIntersects) {
                intersects = getSpatialSearchRow(intersects, columnId, v);
            }
            // an X IN(..) condition, unless the X IN condition can use the index.
            if ((isStart || isEnd) && !canUseIndexFor(inColumn)) {
                inColumn = null;
                inList = null;
                inResult = null;
            }
            if (!session.getDatabase().getSettings().optimizeIsNull) {
                if (isStart && isEnd) {
                    if (v == ValueNull.INSTANCE) {
                        // join on a column=NULL is always false
                        alwaysFalse = true;
                    }
                }
            }
        }
    }
    if (inColumn != null) {
        start = table.getTemplateRow();
    }
}

Example 12 with Cursor

use of org.h2.mvstore.Cursor in project h2database by h2database.

the class PageBtreeIndex method findFirstOrLast.

@Override
public Cursor findFirstOrLast(Session session, boolean first) {
    if (first) {
        // TODO optimization: this loops through NULL elements
        Cursor cursor = find(session, null, false, null);
        while (cursor.next()) {
            SearchRow row = cursor.getSearchRow();
            Value v = row.getValue(columnIds[0]);
            if (v != ValueNull.INSTANCE) {
                return cursor;
            }
        }
        return cursor;
    }
    PageBtree root = getPage(rootPageId);
    PageBtreeCursor cursor = new PageBtreeCursor(session, this, null);
    root.last(cursor);
    cursor.previous();
    // TODO optimization: this loops through NULL elements
    do {
        SearchRow row = cursor.getSearchRow();
        if (row == null) {
            break;
        }
        Value v = row.getValue(columnIds[0]);
        if (v != ValueNull.INSTANCE) {
            return cursor;
        }
    } while (cursor.previous());
    return cursor;
}

Example 13 with Cursor

use of org.h2.mvstore.Cursor in project h2database by h2database.

the class Aggregate method getValue.

@Override
public Value getValue(Session session) {
    if (select.isQuickAggregateQuery()) {
        switch(type) {
            case COUNT:
            case COUNT_ALL:
                Table table = select.getTopTableFilter().getTable();
                return ValueLong.get(table.getRowCount(session));
            case MIN:
            case MAX:
                {
                    boolean first = type == AggregateType.MIN;
                    Index index = getMinMaxColumnIndex();
                    int sortType = index.getIndexColumns()[0].sortType;
                    if ((sortType & SortOrder.DESCENDING) != 0) {
                        first = !first;
                    }
                    Cursor cursor = index.findFirstOrLast(session, first);
                    SearchRow row = cursor.getSearchRow();
                    Value v;
                    if (row == null) {
                        v = ValueNull.INSTANCE;
                    } else {
                        v = row.getValue(index.getColumns()[0].getColumnId());
                    }
                    return v;
                }
            case MEDIAN:
                {
                    return AggregateDataMedian.getResultFromIndex(session, on, dataType);
                }
            default:
                DbException.throwInternalError("type=" + type);
        }
    }
    HashMap<Expression, Object> group = select.getCurrentGroup();
    if (group == null) {
        throw DbException.get(ErrorCode.INVALID_USE_OF_AGGREGATE_FUNCTION_1, getSQL());
    }
    AggregateData data = (AggregateData) group.get(this);
    if (data == null) {
        data = AggregateData.create(type);
    }
    if (type == AggregateType.GROUP_CONCAT) {
        Value[] array = ((AggregateDataCollecting) data).getArray();
        if (array == null) {
            return ValueNull.INSTANCE;
        }
        if (orderByList != null || distinct) {
            sortWithOrderBy(array);
        }
        StatementBuilder buff = new StatementBuilder();
        String sep = groupConcatSeparator == null ? "," : groupConcatSeparator.getValue(session).getString();
        for (Value val : array) {
            String s;
            if (val.getType() == Value.ARRAY) {
                s = ((ValueArray) val).getList()[0].getString();
            } else {
                s = val.getString();
            }
            if (s == null) {
                continue;
            }
            if (sep != null) {
                buff.appendExceptFirst(sep);
            }
            buff.append(s);
        }
        return ValueString.get(buff.toString());
    } else if (type == AggregateType.ARRAY_AGG) {
        Value[] array = ((AggregateDataCollecting) data).getArray();
        if (array == null) {
            return ValueNull.INSTANCE;
        }
        if (orderByList != null || distinct) {
            sortWithOrderBy(array);
        }
        if (orderByList != null) {
            for (int i = 0; i < array.length; i++) {
                array[i] = ((ValueArray) array[i]).getList()[0];
            }
        }
        return ValueArray.get(array);
    }
    return data.getValue(session.getDatabase(), dataType, distinct);
}

Example 14 with Cursor

use of org.h2.mvstore.Cursor in project h2database by h2database.

the class LinkedIndex method find.

@Override
public Cursor find(Session session, SearchRow first, SearchRow last) {
    ArrayList<Value> params = New.arrayList();
    StatementBuilder buff = new StatementBuilder("SELECT * FROM ");
    buff.append(targetTableName).append(" T");
    for (int i = 0; first != null && i < first.getColumnCount(); i++) {
        Value v = first.getValue(i);
        if (v != null) {
            buff.appendOnlyFirst(" WHERE ");
            buff.appendExceptFirst(" AND ");
            Column col = table.getColumn(i);
            buff.append(col.getSQL());
            if (v == ValueNull.INSTANCE) {
                buff.append(" IS NULL");
            } else {
                buff.append(">=");
                addParameter(buff, col);
                params.add(v);
            }
        }
    }
    for (int i = 0; last != null && i < last.getColumnCount(); i++) {
        Value v = last.getValue(i);
        if (v != null) {
            buff.appendOnlyFirst(" WHERE ");
            buff.appendExceptFirst(" AND ");
            Column col = table.getColumn(i);
            buff.append(col.getSQL());
            if (v == ValueNull.INSTANCE) {
                buff.append(" IS NULL");
            } else {
                buff.append("<=");
                addParameter(buff, col);
                params.add(v);
            }
        }
    }
    String sql = buff.toString();
    try {
        PreparedStatement prep = link.execute(sql, params, false);
        ResultSet rs = prep.getResultSet();
        return new LinkedCursor(link, rs, session, sql, prep);
    } catch (Exception e) {
        throw TableLink.wrapException(sql, e);
    }
}

Example 15 with Cursor

use of org.h2.mvstore.Cursor in project h2database by h2database.

the class NonUniqueHashIndex method find.

@Override
public Cursor find(Session session, SearchRow first, SearchRow last) {
    if (first == null || last == null) {
        throw DbException.throwInternalError(first + " " + last);
    }
    if (first != last) {
        if (compareKeys(first, last) != 0) {
            throw DbException.throwInternalError();
        }
    }
    Value v = first.getValue(indexColumn);
    /*
         * Sometimes the incoming search is a similar, but not the same type
         * e.g. the search value is INT, but the index column is LONG. In which
         * case we need to convert, otherwise the ValueHashMap will not find the
         * result.
         */
    v = v.convertTo(tableData.getColumn(indexColumn).getType());
    ArrayList<Long> positions = rows.get(v);
    return new NonUniqueHashCursor(session, tableData, positions);
}