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

Example 1 with IndexHints

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

the class TableFilter method getPlanSQL.

/**
 * Get the query execution plan text to use for this table filter.
 *
 * @param isJoin if this is a joined table
 * @return the SQL statement snippet
 */
public String getPlanSQL(boolean isJoin) {
    StringBuilder buff = new StringBuilder();
    if (isJoin) {
        if (joinOuter) {
            buff.append("LEFT OUTER JOIN ");
        } else {
            buff.append("INNER JOIN ");
        }
    }
    if (nestedJoin != null) {
        StringBuilder buffNested = new StringBuilder();
        TableFilter n = nestedJoin;
        do {
            buffNested.append(n.getPlanSQL(n != nestedJoin));
            buffNested.append('\n');
            n = n.getJoin();
        } while (n != null);
        String nested = buffNested.toString();
        boolean enclose = !nested.startsWith("(");
        if (enclose) {
            buff.append("(\n");
        }
        buff.append(StringUtils.indent(nested, 4, false));
        if (enclose) {
            buff.append(')');
        }
        if (isJoin) {
            buff.append(" ON ");
            if (joinCondition == null) {
                // need to have a ON expression,
                // otherwise the nesting is unclear
                buff.append("1=1");
            } else {
                buff.append(StringUtils.unEnclose(joinCondition.getSQL()));
            }
        }
        return buff.toString();
    }
    if (table.isView() && ((TableView) table).isRecursive()) {
        buff.append(table.getName());
    } else {
        buff.append(table.getSQL());
    }
    if (table.isView() && ((TableView) table).isInvalid()) {
        throw DbException.get(ErrorCode.VIEW_IS_INVALID_2, table.getName(), "not compiled");
    }
    if (alias != null) {
        buff.append(' ').append(Parser.quoteIdentifier(alias));
    }
    if (indexHints != null) {
        buff.append(" USE INDEX (");
        boolean first = true;
        for (String index : indexHints.getAllowedIndexes()) {
            if (!first) {
                buff.append(", ");
            } else {
                first = false;
            }
            buff.append(Parser.quoteIdentifier(index));
        }
        buff.append(")");
    }
    if (index != null) {
        buff.append('\n');
        StatementBuilder planBuff = new StatementBuilder();
        if (joinBatch != null) {
            IndexLookupBatch lookupBatch = joinBatch.getLookupBatch(joinFilterId);
            if (lookupBatch == null) {
                if (joinFilterId != 0) {
                    throw DbException.throwInternalError("" + joinFilterId);
                }
            } else {
                planBuff.append("batched:");
                String batchPlan = lookupBatch.getPlanSQL();
                planBuff.append(batchPlan);
                planBuff.append(" ");
            }
        }
        planBuff.append(index.getPlanSQL());
        if (!indexConditions.isEmpty()) {
            planBuff.append(": ");
            for (IndexCondition condition : indexConditions) {
                planBuff.appendExceptFirst("\n    AND ");
                planBuff.append(condition.getSQL());
            }
        }
        String plan = StringUtils.quoteRemarkSQL(planBuff.toString());
        if (plan.indexOf('\n') >= 0) {
            plan += "\n";
        }
        buff.append(StringUtils.indent("/* " + plan + " */", 4, false));
    }
    if (isJoin) {
        buff.append("\n    ON ");
        if (joinCondition == null) {
            // need to have a ON expression, otherwise the nesting is
            // unclear
            buff.append("1=1");
        } else {
            buff.append(StringUtils.unEnclose(joinCondition.getSQL()));
        }
    }
    if (filterCondition != null) {
        buff.append('\n');
        String condition = StringUtils.unEnclose(filterCondition.getSQL());
        condition = "/* WHERE " + StringUtils.quoteRemarkSQL(condition) + "\n*/";
        buff.append(StringUtils.indent(condition, 4, false));
    }
    if (scanCount > 0) {
        buff.append("\n    /* scanCount: ").append(scanCount).append(" */");
    }
    return buff.toString();
}

Example 2 with IndexHints

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

the class Table method getBestPlanItem.

/**
 * Get the best plan for the given search mask.
 *
 * @param session the session
 * @param masks per-column comparison bit masks, null means 'always false',
 *              see constants in IndexCondition
 * @param filters all joined table filters
 * @param filter the current table filter index
 * @param sortOrder the sort order
 * @param allColumnsSet the set of all columns
 * @return the plan item
 */
public PlanItem getBestPlanItem(Session session, int[] masks, TableFilter[] filters, int filter, SortOrder sortOrder, HashSet<Column> allColumnsSet) {
    PlanItem item = new PlanItem();
    item.setIndex(getScanIndex(session));
    item.cost = item.getIndex().getCost(session, null, filters, filter, null, allColumnsSet);
    Trace t = session.getTrace();
    if (t.isDebugEnabled()) {
        t.debug("Table      :     potential plan item cost {0} index {1}", item.cost, item.getIndex().getPlanSQL());
    }
    ArrayList<Index> indexes = getIndexes();
    IndexHints indexHints = getIndexHints(filters, filter);
    if (indexes != null && masks != null) {
        for (int i = 1, size = indexes.size(); i < size; i++) {
            Index index = indexes.get(i);
            if (isIndexExcludedByHints(indexHints, index)) {
                continue;
            }
            double cost = index.getCost(session, masks, filters, filter, sortOrder, allColumnsSet);
            if (t.isDebugEnabled()) {
                t.debug("Table      :     potential plan item cost {0} index {1}", cost, index.getPlanSQL());
            }
            if (cost < item.cost) {
                item.cost = cost;
                item.setIndex(index);
            }
        }
    }
    return item;
}

Example 3 with IndexHints

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

the class Parser method parseIndexHints.

private IndexHints parseIndexHints(Table table) {
    if (table == null) {
        throw getSyntaxError();
    }
    read("(");
    LinkedHashSet<String> indexNames = new LinkedHashSet<>();
    if (!readIf(")")) {
        do {
            String indexName = readIdentifierWithSchema();
            Index index = table.getIndex(indexName);
            indexNames.add(index.getName());
        } while (readIfMore(true));
    }
    return IndexHints.createUseIndexHints(indexNames);
}

Example 4 with IndexHints

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

the class Parser method readTableFilter.

private TableFilter readTableFilter() {
    Table table;
    String alias = null;
    if (readIf("(")) {
        if (isSelect()) {
            Query query = parseSelectUnion();
            read(")");
            query.setParameterList(new ArrayList<>(parameters));
            query.init();
            Session s;
            if (createView != null) {
                s = database.getSystemSession();
            } else {
                s = session;
            }
            alias = session.getNextSystemIdentifier(sqlCommand);
            table = TableView.createTempView(s, session.getUser(), alias, query, currentSelect);
        } else {
            TableFilter top;
            top = readTableFilter();
            top = readJoin(top);
            read(")");
            alias = readFromAlias(null);
            if (alias != null) {
                top.setAlias(alias);
                ArrayList<String> derivedColumnNames = readDerivedColumnNames();
                if (derivedColumnNames != null) {
                    top.setDerivedColumns(derivedColumnNames);
                }
            }
            return top;
        }
    } else if (readIf("VALUES")) {
        table = parseValuesTable(0).getTable();
    } else {
        String tableName = readIdentifierWithSchema(null);
        Schema schema = getSchema();
        boolean foundLeftBracket = readIf("(");
        if (foundLeftBracket && readIf("INDEX")) {
            // Sybase compatibility with
            // "select * from test (index table1_index)"
            readIdentifierWithSchema(null);
            read(")");
            foundLeftBracket = false;
        }
        if (foundLeftBracket) {
            Schema mainSchema = database.getSchema(Constants.SCHEMA_MAIN);
            if (equalsToken(tableName, RangeTable.NAME) || equalsToken(tableName, RangeTable.ALIAS)) {
                Expression min = readExpression();
                read(",");
                Expression max = readExpression();
                if (readIf(",")) {
                    Expression step = readExpression();
                    read(")");
                    table = new RangeTable(mainSchema, min, max, step, false);
                } else {
                    read(")");
                    table = new RangeTable(mainSchema, min, max, false);
                }
            } else {
                Expression expr = readFunction(schema, tableName);
                if (!(expr instanceof FunctionCall)) {
                    throw getSyntaxError();
                }
                FunctionCall call = (FunctionCall) expr;
                if (!call.isDeterministic()) {
                    recompileAlways = true;
                }
                table = new FunctionTable(mainSchema, session, expr, call);
            }
        } else if (equalsToken("DUAL", tableName)) {
            table = getDualTable(false);
        } else if (database.getMode().sysDummy1 && equalsToken("SYSDUMMY1", tableName)) {
            table = getDualTable(false);
        } else {
            table = readTableOrView(tableName);
        }
    }
    ArrayList<String> derivedColumnNames = null;
    IndexHints indexHints = null;
    // for backward compatibility, handle case where USE is a table alias
    if (readIf("USE")) {
        if (readIf("INDEX")) {
            indexHints = parseIndexHints(table);
        } else {
            alias = "USE";
            derivedColumnNames = readDerivedColumnNames();
        }
    } else {
        alias = readFromAlias(alias);
        if (alias != null) {
            derivedColumnNames = readDerivedColumnNames();
            // if alias present, a second chance to parse index hints
            if (readIf("USE")) {
                read("INDEX");
                indexHints = parseIndexHints(table);
            }
        }
    }
    // inherit alias for CTE as views from table name
    if (table.isView() && table.isTableExpression() && alias == null) {
        alias = table.getName();
    }
    TableFilter filter = new TableFilter(session, table, alias, rightsChecked, currentSelect, orderInFrom++, indexHints);
    if (derivedColumnNames != null) {
        filter.setDerivedColumns(derivedColumnNames);
    }
    return filter;
}