/*
* 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 java.util.concurrent.TimeUnit;
import org.h2.api.ErrorCode;
import org.h2.command.Parser;
import org.h2.command.query.AllColumnsForPlan;
import org.h2.command.query.Query;
import org.h2.command.query.SelectUnion;
import org.h2.engine.Constants;
import org.h2.engine.SessionLocal;
import org.h2.expression.Parameter;
import org.h2.expression.condition.Comparison;
import org.h2.message.DbException;
import org.h2.result.LocalResult;
import org.h2.result.ResultInterface;
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.QueryExpressionTable;
import org.h2.table.TableFilter;
import org.h2.table.TableView;
import org.h2.util.IntArray;
import org.h2.value.Value;
/**
* This object represents a virtual index for a query expression.
*/
public class QueryExpressionIndex extends Index implements SpatialIndex {
private static final long MAX_AGE_NANOS =
TimeUnit.MILLISECONDS.toNanos(Constants.VIEW_COST_CACHE_MAX_AGE);
private final QueryExpressionTable table;
private final String querySQL;
private final ArrayList<Parameter> originalParameters;
private boolean recursive;
private final int[] indexMasks;
private Query query;
private final SessionLocal createSession;
/**
* The time in nanoseconds when this index (and its cost) was calculated.
*/
private final long evaluatedAt;
/**
* Constructor for the original index in {@link TableView}.
*
* @param table the query expression table
* @param querySQL the query SQL
* @param originalParameters the original parameters
* @param recursive if the view is recursive
*/
public QueryExpressionIndex(QueryExpressionTable table, String querySQL,
ArrayList<Parameter> originalParameters, boolean recursive) {
super(table, 0, null, null, 0, IndexType.createNonUnique(false));
this.table = table;
this.querySQL = querySQL;
this.originalParameters = originalParameters;
this.recursive = recursive;
columns = new Column[0];
this.createSession = null;
this.indexMasks = null;
// this is a main index of TableView, it does not need eviction time
// stamp
evaluatedAt = Long.MIN_VALUE;
}
/**
* Constructor for plan item generation. Over this index the query will be
* executed.
*
* @param table the query expression table
* @param index the main index
* @param session the session
* @param masks the masks
* @param filters table filters
* @param filter current filter
* @param sortOrder sort order
*/
public QueryExpressionIndex(QueryExpressionTable table, QueryExpressionIndex index, SessionLocal session,
int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder) {
super(table, 0, null, null, 0, IndexType.createNonUnique(false));
this.table = table;
this.querySQL = index.querySQL;
this.originalParameters = index.originalParameters;
this.recursive = index.recursive;
this.indexMasks = masks;
this.createSession = session;
columns = new Column[0];
if (!recursive) {
query = getQuery(session, masks);
}
if (recursive || table.getTopQuery() != null) {
evaluatedAt = Long.MAX_VALUE;
} else {
long time = System.nanoTime();
if (time == Long.MAX_VALUE) {
time++;
}
evaluatedAt = time;
}
}
public SessionLocal getSession() {
return createSession;
}
public boolean isExpired() {
assert evaluatedAt != Long.MIN_VALUE : "must not be called for main index of TableView";
return !recursive && table.getTopQuery() == null && System.nanoTime() - evaluatedAt > MAX_AGE_NANOS;
}
@Override
public String getPlanSQL() {
return query == null ? null : query.getPlanSQL(TRACE_SQL_FLAGS | ADD_PLAN_INFORMATION);
}
@Override
public void close(SessionLocal session) {
// nothing to do
}
@Override
public void add(SessionLocal session, Row row) {
throw DbException.getUnsupportedException("VIEW");
}
@Override
public void remove(SessionLocal session, Row row) {
throw DbException.getUnsupportedException("VIEW");
}
@Override
public double getCost(SessionLocal session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
AllColumnsForPlan allColumnsSet) {
return recursive ? 1000 : query.getCost();
}
@Override
public Cursor find(SessionLocal session, SearchRow first, SearchRow last) {
return find(session, first, last, null);
}
@Override
public Cursor findByGeometry(SessionLocal session, SearchRow first, SearchRow last, SearchRow intersection) {
return find(session, first, last, intersection);
}
private Cursor findRecursive(SearchRow first, SearchRow last) {
TableView view = (TableView) table;
ResultInterface recursiveResult = view.getRecursiveResult();
if (recursiveResult != null) {
recursiveResult.reset();
return new QueryExpressionCursor(this, recursiveResult, first, last);
}
if (query == null) {
Parser parser = new Parser(createSession);
parser.setRightsChecked(true);
parser.setSuppliedParameters(originalParameters);
query = (Query) parser.prepare(querySQL);
query.setNeverLazy(true);
}
if (!query.isUnion()) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_2,
"recursive queries without UNION");
}
SelectUnion union = (SelectUnion) query;
Query left = union.getLeft();
left.setNeverLazy(true);
// to ensure the last result is not closed
left.disableCache();
ResultInterface resultInterface = left.query(0);
LocalResult localResult = union.getEmptyResult();
// ensure it is not written to disk,
// because it is not closed normally
localResult.setMaxMemoryRows(Integer.MAX_VALUE);
while (resultInterface.next()) {
Value[] cr = resultInterface.currentRow();
localResult.addRow(cr);
}
Query right = union.getRight();
right.setNeverLazy(true);
resultInterface.reset();
view.setRecursiveResult(resultInterface);
// to ensure the last result is not closed
right.disableCache();
while (true) {
resultInterface = right.query(0);
if (!resultInterface.hasNext()) {
break;
}
while (resultInterface.next()) {
Value[] cr = resultInterface.currentRow();
localResult.addRow(cr);
}
resultInterface.reset();
view.setRecursiveResult(resultInterface);
}
view.setRecursiveResult(null);
localResult.done();
return new QueryExpressionCursor(this, localResult, first, last);
}
/**
* Set the query parameters.
*
* @param session the session
* @param first the lower bound
* @param last the upper bound
* @param intersection the intersection
*/
public void setupQueryParameters(SessionLocal session, SearchRow first, SearchRow last,
SearchRow intersection) {
ArrayList<Parameter> paramList = query.getParameters();
if (originalParameters != null) {
for (Parameter orig : originalParameters) {
if (orig != null) {
int idx = orig.getIndex();
Value value = orig.getValue(session);
setParameter(paramList, idx, value);
}
}
}
int len;
if (first != null) {
len = first.getColumnCount();
} else if (last != null) {
len = last.getColumnCount();
} else if (intersection != null) {
len = intersection.getColumnCount();
} else {
len = 0;
}
int idx = table.getParameterOffset(originalParameters);
for (int i = 0; i < len; i++) {
int mask = indexMasks[i];
if ((mask & IndexCondition.EQUALITY) != 0) {
setParameter(paramList, idx++, first.getValue(i));
}
if ((mask & IndexCondition.START) != 0) {
setParameter(paramList, idx++, first.getValue(i));
}
if ((mask & IndexCondition.END) != 0) {
setParameter(paramList, idx++, last.getValue(i));
}
if ((mask & IndexCondition.SPATIAL_INTERSECTS) != 0) {
setParameter(paramList, idx++, intersection.getValue(i));
}
}
}
private Cursor find(SessionLocal session, SearchRow first, SearchRow last,
SearchRow intersection) {
if (recursive) {
return findRecursive(first, last);
}
setupQueryParameters(session, first, last, intersection);
ResultInterface result = query.query(0);
return new QueryExpressionCursor(this, result, first, last);
}
private static void setParameter(ArrayList<Parameter> paramList, int x,
Value v) {
if (x >= paramList.size()) {
// the parameter may be optimized away as in
// select * from (select null as x) where x=1;
return;
}
Parameter param = paramList.get(x);
param.setValue(v);
}
public Query getQuery() {
return query;
}
private Query getQuery(SessionLocal session, int[] masks) {
Query q = session.prepareQueryExpression(querySQL);
if (masks == null || !q.allowGlobalConditions()) {
q.preparePlan();
return q;
}
int firstIndexParam = table.getParameterOffset(originalParameters);
// the column index of each parameter
// (for example: paramColumnIndex {0, 0} mean
// param[0] is column 0, and param[1] is also column 0)
IntArray paramColumnIndex = new IntArray();
int indexColumnCount = 0;
for (int i = 0; i < masks.length; i++) {
int mask = masks[i];
if (mask == 0) {
continue;
}
indexColumnCount++;
// the number of parameters depends on the mask;
// for range queries it is 2: >= x AND <= y
// but bitMask could also be 7 (=, and <=, and >=)
int bitCount = Integer.bitCount(mask);
for (int j = 0; j < bitCount; j++) {
paramColumnIndex.add(i);
}
}
int len = paramColumnIndex.size();
ArrayList<Column> columnList = new ArrayList<>(len);
for (int i = 0; i < len;) {
int idx = paramColumnIndex.get(i);
columnList.add(table.getColumn(idx));
int mask = masks[idx];
if ((mask & IndexCondition.EQUALITY) != 0) {
Parameter param = new Parameter(firstIndexParam + i);
q.addGlobalCondition(param, idx, Comparison.EQUAL_NULL_SAFE);
i++;
}
if ((mask & IndexCondition.START) != 0) {
Parameter param = new Parameter(firstIndexParam + i);
q.addGlobalCondition(param, idx, Comparison.BIGGER_EQUAL);
i++;
}
if ((mask & IndexCondition.END) != 0) {
Parameter param = new Parameter(firstIndexParam + i);
q.addGlobalCondition(param, idx, Comparison.SMALLER_EQUAL);
i++;
}
if ((mask & IndexCondition.SPATIAL_INTERSECTS) != 0) {
Parameter param = new Parameter(firstIndexParam + i);
q.addGlobalCondition(param, idx, Comparison.SPATIAL_INTERSECTS);
i++;
}
}
columns = columnList.toArray(new Column[0]);
// reconstruct the index columns from the masks
this.indexColumns = new IndexColumn[indexColumnCount];
this.columnIds = new int[indexColumnCount];
for (int type = 0, indexColumnId = 0; type < 2; type++) {
for (int i = 0; i < masks.length; i++) {
int mask = masks[i];
if (mask == 0) {
continue;
}
if (type == 0) {
if ((mask & IndexCondition.EQUALITY) == 0) {
// the first columns need to be equality conditions
continue;
}
} else {
if ((mask & IndexCondition.EQUALITY) != 0) {
// after that only range conditions
continue;
}
}
Column column = table.getColumn(i);
indexColumns[indexColumnId] = new IndexColumn(column);
columnIds[indexColumnId] = column.getColumnId();
indexColumnId++;
}
}
String sql = q.getPlanSQL(DEFAULT_SQL_FLAGS);
if (!sql.equals(querySQL)) {
q = session.prepareQueryExpression(sql);
}
q.preparePlan();
return q;
}
@Override
public void remove(SessionLocal session) {
throw DbException.getUnsupportedException("VIEW");
}
@Override
public void truncate(SessionLocal session) {
throw DbException.getUnsupportedException("VIEW");
}
@Override
public void checkRename() {
throw DbException.getUnsupportedException("VIEW");
}
@Override
public boolean needRebuild() {
return false;
}
public void setRecursive(boolean value) {
this.recursive = value;
}
@Override
public long getRowCount(SessionLocal session) {
return 0;
}
@Override
public long getRowCountApproximation(SessionLocal session) {
return 0;
}
public boolean isRecursive() {
return recursive;
}
}