Examples with Explain org.h2.command.dml.Explain used on opensource projects

Example 21 with Explain

use of org.h2.command.dml.Explain in project ignite by apache.

the class GridSqlDelete method getSQL.

/**
 * {@inheritDoc}
 */
@Override
public String getSQL() {
    StatementBuilder buff = new StatementBuilder(explain() ? "EXPLAIN " : "");
    buff.append("DELETE").append("\nFROM ").append(from.getSQL());
    if (where != null)
        buff.append("\nWHERE ").append(StringUtils.unEnclose(where.getSQL()));
    if (limit != null)
        buff.append("\nLIMIT (").append(StringUtils.unEnclose(limit.getSQL())).append(')');
    return buff.toString();
}

Example 22 with Explain

use of org.h2.command.dml.Explain in project ignite by apache.

the class GridSqlQuerySplitter method split.

/**
 * @param conn Connection.
 * @param prepared Prepared.
 * @param params Parameters.
 * @param collocatedGrpBy Whether the query has collocated GROUP BY keys.
 * @param distributedJoins If distributed joins enabled.
 * @param enforceJoinOrder Enforce join order.
 * @param h2 Indexing.
 * @return Two step query.
 * @throws SQLException If failed.
 * @throws IgniteCheckedException If failed.
 */
public static GridCacheTwoStepQuery split(Connection conn, Prepared prepared, Object[] params, boolean collocatedGrpBy, boolean distributedJoins, boolean enforceJoinOrder, IgniteH2Indexing h2) throws SQLException, IgniteCheckedException {
    if (params == null)
        params = GridCacheSqlQuery.EMPTY_PARAMS;
    // Here we will just do initial query parsing. Do not use optimized
    // subqueries because we do not have unique FROM aliases yet.
    GridSqlQuery qry = parse(prepared, false);
    String originalSql = qry.getSQL();
    // debug("ORIGINAL", originalSql);
    final boolean explain = qry.explain();
    qry.explain(false);
    GridSqlQuerySplitter splitter = new GridSqlQuerySplitter(params, collocatedGrpBy, h2.kernalContext());
    // Normalization will generate unique aliases for all the table filters in FROM.
    // Also it will collect all tables and schemas from the query.
    splitter.normalizeQuery(qry);
    // debug("NORMALIZED", qry.getSQL());
    // Here we will have correct normalized AST with optimized join order.
    // The distributedJoins parameter is ignored because it is not relevant for
    // the REDUCE query optimization.
    qry = parse(optimize(h2, conn, qry.getSQL(), params, false, enforceJoinOrder), true);
    // Do the actual query split. We will update the original query AST, need to be careful.
    splitter.splitQuery(qry);
    // We must have at least one map query.
    assert !F.isEmpty(splitter.mapSqlQrys) : "map";
    // We must have a reduce query.
    assert splitter.rdcSqlQry != null : "rdc";
    // distributed joins at all.
    if (distributedJoins) {
        boolean allCollocated = true;
        for (GridCacheSqlQuery mapSqlQry : splitter.mapSqlQrys) {
            Prepared prepared0 = optimize(h2, conn, mapSqlQry.query(), mapSqlQry.parameters(params), true, enforceJoinOrder);
            allCollocated &= isCollocated((Query) prepared0);
            mapSqlQry.query(parse(prepared0, true).getSQL());
        }
        // We do not need distributed joins if all MAP queries are collocated.
        if (allCollocated)
            distributedJoins = false;
    }
    // Setup resulting two step query and return it.
    GridCacheTwoStepQuery twoStepQry = new GridCacheTwoStepQuery(originalSql, splitter.tbls);
    twoStepQry.reduceQuery(splitter.rdcSqlQry);
    for (GridCacheSqlQuery mapSqlQry : splitter.mapSqlQrys) twoStepQry.addMapQuery(mapSqlQry);
    twoStepQry.skipMergeTable(splitter.rdcQrySimple);
    twoStepQry.explain(explain);
    twoStepQry.distributedJoins(distributedJoins);
    // all map queries must have non-empty derivedPartitions to use this feature.
    twoStepQry.derivedPartitions(mergePartitionsFromMultipleQueries(twoStepQry.mapQueries()));
    return twoStepQry;
}

Example 23 with Explain

use of org.h2.command.dml.Explain in project ignite by apache.

the class GridSqlSelect method getSQL.

/**
 * {@inheritDoc}
 */
@Override
public String getSQL() {
    StatementBuilder buff = new StatementBuilder(explain() ? "EXPLAIN SELECT" : "SELECT");
    if (distinct)
        buff.append(" DISTINCT");
    for (GridSqlAst expression : columns(true)) {
        buff.appendExceptFirst(",");
        buff.append('\n');
        buff.append(expression.getSQL());
    }
    if (from != null)
        buff.append("\nFROM ").append(from.getSQL());
    if (where != null)
        buff.append("\nWHERE ").append(StringUtils.unEnclose(where.getSQL()));
    if (grpCols != null) {
        buff.append("\nGROUP BY ");
        buff.resetCount();
        for (int grpCol : grpCols) {
            buff.appendExceptFirst(", ");
            addAlias(buff, cols.get(grpCol));
        }
    }
    if (havingCol >= 0) {
        buff.append("\nHAVING ");
        addAlias(buff, cols.get(havingCol));
    }
    getSortLimitSQL(buff);
    return buff.toString();
}

Example 24 with Explain

use of org.h2.command.dml.Explain in project h2database by h2database.

the class CommandRemote method sendParameters.

private void sendParameters(Transfer transfer) throws IOException {
    int len = parameters.size();
    transfer.writeInt(len);
    for (ParameterInterface p : parameters) {
        Value pVal = p.getParamValue();
        if (pVal == null && cmdType == EXPLAIN) {
            pVal = ValueNull.INSTANCE;
        }
        transfer.writeValue(pVal);
    }
}

Example 25 with Explain

use of org.h2.command.dml.Explain in project h2database by h2database.

the class Parser method parseExplain.

private Explain parseExplain() {
    Explain command = new Explain(session);
    if (readIf("ANALYZE")) {
        command.setExecuteCommand(true);
    } else {
        if (readIf("PLAN")) {
            readIf("FOR");
        }
    }
    if (isToken("SELECT") || isToken("FROM") || isToken("(") || isToken("WITH")) {
        Query query = parseSelect();
        query.setNeverLazy(true);
        command.setCommand(query);
    } else if (readIf("DELETE")) {
        command.setCommand(parseDelete());
    } else if (readIf("UPDATE")) {
        command.setCommand(parseUpdate());
    } else if (readIf("INSERT")) {
        command.setCommand(parseInsert());
    } else if (readIf("MERGE")) {
        command.setCommand(parseMerge());
    } else {
        throw getSyntaxError();
    }
    return command;
}