Examples with PlanItem org.h2.table.PlanItem used on opensource projects

Example 1 with PlanItem

use of org.h2.table.PlanItem in project h2database by h2database.

the class Delete method prepare.

@Override
public void prepare() {
    if (condition != null) {
        condition.mapColumns(targetTableFilter, 0);
        if (sourceTableFilter != null) {
            condition.mapColumns(sourceTableFilter, 0);
        }
        condition = condition.optimize(session);
        condition.createIndexConditions(session, targetTableFilter);
    }
    TableFilter[] filters;
    if (sourceTableFilter == null) {
        filters = new TableFilter[] { targetTableFilter };
    } else {
        filters = new TableFilter[] { targetTableFilter, sourceTableFilter };
    }
    PlanItem item = targetTableFilter.getBestPlanItem(session, filters, 0, ExpressionVisitor.allColumnsForTableFilters(filters));
    targetTableFilter.setPlanItem(item);
    targetTableFilter.prepare();
}

Example 2 with PlanItem

use of org.h2.table.PlanItem in project h2database by h2database.

the class TableFilter method getBestPlanItem.

/**
 * Get the best plan item (index, cost) to use use for the current join
 * order.
 *
 * @param s the session
 * @param filters all joined table filters
 * @param filter the current table filter index
 * @param allColumnsSet the set of all columns
 * @return the best plan item
 */
public PlanItem getBestPlanItem(Session s, TableFilter[] filters, int filter, HashSet<Column> allColumnsSet) {
    PlanItem item1 = null;
    SortOrder sortOrder = null;
    if (select != null) {
        sortOrder = select.getSortOrder();
    }
    if (indexConditions.isEmpty()) {
        item1 = new PlanItem();
        item1.setIndex(table.getScanIndex(s, null, filters, filter, sortOrder, allColumnsSet));
        item1.cost = item1.getIndex().getCost(s, null, filters, filter, sortOrder, allColumnsSet);
    }
    int len = table.getColumns().length;
    int[] masks = new int[len];
    for (IndexCondition condition : indexConditions) {
        if (condition.isEvaluatable()) {
            if (condition.isAlwaysFalse()) {
                masks = null;
                break;
            }
            int id = condition.getColumn().getColumnId();
            if (id >= 0) {
                masks[id] |= condition.getMask(indexConditions);
            }
        }
    }
    PlanItem item = table.getBestPlanItem(s, masks, filters, filter, sortOrder, allColumnsSet);
    item.setMasks(masks);
    // The more index conditions, the earlier the table.
    // This is to ensure joins without indexes run quickly:
    // x (x.a=10); y (x.b=y.b) - see issue 113
    item.cost -= item.cost * indexConditions.size() / 100 / (filter + 1);
    if (item1 != null && item1.cost < item.cost) {
        item = item1;
    }
    if (nestedJoin != null) {
        setEvaluatable(true);
        item.setNestedJoinPlan(nestedJoin.getBestPlanItem(s, filters, filter, allColumnsSet));
        // TODO optimizer: calculate cost of a join: should use separate
        // expected row number and lookup cost
        item.cost += item.cost * item.getNestedJoinPlan().cost;
    }
    if (join != null) {
        setEvaluatable(true);
        do {
            filter++;
        } while (filters[filter] != join);
        item.setJoinPlan(join.getBestPlanItem(s, filters, filter, allColumnsSet));
        // TODO optimizer: calculate cost of a join: should use separate
        // expected row number and lookup cost
        item.cost += item.cost * item.getJoinPlan().cost;
    }
    return item;
}

Example 3 with PlanItem

use of org.h2.table.PlanItem in project h2database by h2database.

the class Optimizer method optimize.

/**
 * Calculate the best query plan to use.
 *
 * @param parse If we do not need to really get the best plan because it is
 *            a view parsing stage.
 */
void optimize(boolean parse) {
    if (parse) {
        calculateFakePlan();
    } else {
        calculateBestPlan();
        bestPlan.removeUnusableIndexConditions();
    }
    TableFilter[] f2 = bestPlan.getFilters();
    topFilter = f2[0];
    for (int i = 0; i < f2.length - 1; i++) {
        f2[i].addJoin(f2[i + 1], false, null);
    }
    if (parse) {
        return;
    }
    for (TableFilter f : f2) {
        PlanItem item = bestPlan.getItem(f);
        f.setPlanItem(item);
    }
}

Example 4 with PlanItem

use of org.h2.table.PlanItem in project h2database by h2database.

the class ScriptCommand method generateInsertValues.

private int generateInsertValues(int count, Table table) throws IOException {
    PlanItem plan = table.getBestPlanItem(session, null, null, -1, null, null);
    Index index = plan.getIndex();
    Cursor cursor = index.find(session, null, null);
    Column[] columns = table.getColumns();
    StatementBuilder buff = new StatementBuilder("INSERT INTO ");
    buff.append(table.getSQL()).append('(');
    for (Column col : columns) {
        buff.appendExceptFirst(", ");
        buff.append(Parser.quoteIdentifier(col.getName()));
    }
    buff.append(") VALUES");
    if (!simple) {
        buff.append('\n');
    }
    buff.append('(');
    String ins = buff.toString();
    buff = null;
    while (cursor.next()) {
        Row row = cursor.get();
        if (buff == null) {
            buff = new StatementBuilder(ins);
        } else {
            buff.append(",\n(");
        }
        for (int j = 0; j < row.getColumnCount(); j++) {
            if (j > 0) {
                buff.append(", ");
            }
            Value v = row.getValue(j);
            if (v.getPrecision() > lobBlockSize) {
                int id;
                if (v.getType() == Value.CLOB) {
                    id = writeLobStream(v);
                    buff.append("SYSTEM_COMBINE_CLOB(").append(id).append(')');
                } else if (v.getType() == Value.BLOB) {
                    id = writeLobStream(v);
                    buff.append("SYSTEM_COMBINE_BLOB(").append(id).append(')');
                } else {
                    buff.append(v.getSQL());
                }
            } else {
                buff.append(v.getSQL());
            }
        }
        buff.append(')');
        count++;
        if ((count & 127) == 0) {
            checkCanceled();
        }
        if (simple || buff.length() > Constants.IO_BUFFER_SIZE) {
            add(buff.toString(), true);
            buff = null;
        }
    }
    if (buff != null) {
        add(buff.toString(), true);
    }
    return count;
}

Example 5 with PlanItem

use of org.h2.table.PlanItem in project h2database by h2database.

the class Update method prepare.

@Override
public void prepare() {
    if (condition != null) {
        condition.mapColumns(targetTableFilter, 0);
        condition = condition.optimize(session);
        condition.createIndexConditions(session, targetTableFilter);
    }
    for (Column c : columns) {
        Expression e = expressionMap.get(c);
        e.mapColumns(targetTableFilter, 0);
        if (sourceTableFilter != null) {
            e.mapColumns(sourceTableFilter, 0);
        }
        expressionMap.put(c, e.optimize(session));
    }
    TableFilter[] filters;
    if (sourceTableFilter == null) {
        filters = new TableFilter[] { targetTableFilter };
    } else {
        filters = new TableFilter[] { targetTableFilter, sourceTableFilter };
    }
    PlanItem item = targetTableFilter.getBestPlanItem(session, filters, 0, ExpressionVisitor.allColumnsForTableFilters(filters));
    targetTableFilter.setPlanItem(item);
    targetTableFilter.prepare();
}