/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.index;
import java.util.ArrayList;
import org.h2.command.query.AllColumnsForPlan;
import org.h2.engine.SessionLocal;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.MetaTable;
import org.h2.table.TableFilter;
/**
* The index implementation for meta data tables.
*/
public class MetaIndex extends Index {
private final MetaTable meta;
private final boolean scan;
public MetaIndex(MetaTable meta, IndexColumn[] columns, boolean scan) {
super(meta, 0, null, columns, 0, IndexType.createNonUnique(true));
this.meta = meta;
this.scan = scan;
}
@Override
public void close(SessionLocal session) {
// nothing to do
}
@Override
public void add(SessionLocal session, Row row) {
throw DbException.getUnsupportedException("META");
}
@Override
public void remove(SessionLocal session, Row row) {
throw DbException.getUnsupportedException("META");
}
@Override
public Cursor find(SessionLocal session, SearchRow first, SearchRow last) {
ArrayList<Row> rows = meta.generateRows(session, first, last);
return new MetaCursor(rows);
}
@Override
public double getCost(SessionLocal session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
if (scan) {
return 10 * MetaTable.ROW_COUNT_APPROXIMATION;
}
return getCostRangeIndex(masks, MetaTable.ROW_COUNT_APPROXIMATION,
filters, filter, sortOrder, false, allColumnsSet);
}
@Override
public void truncate(SessionLocal session) {
throw DbException.getUnsupportedException("META");
}
@Override
public void remove(SessionLocal session) {
throw DbException.getUnsupportedException("META");
}
@Override
public int getColumnIndex(Column col) {
if (scan) {
// the scan index cannot use any columns
return -1;
}
return super.getColumnIndex(col);
}
@Override
public boolean isFirstColumn(Column column) {
if (scan) {
return false;
}
return super.isFirstColumn(column);
}
@Override
public void checkRename() {
throw DbException.getUnsupportedException("META");
}
@Override
public boolean needRebuild() {
return false;
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public long getRowCount(SessionLocal session) {
return MetaTable.ROW_COUNT_APPROXIMATION;
}
@Override
public long getRowCountApproximation(SessionLocal session) {
return MetaTable.ROW_COUNT_APPROXIMATION;
}
@Override
public long getDiskSpaceUsed() {
return meta.getDiskSpaceUsed();
}
@Override
public String getPlanSQL() {
return "meta";
}
}