Some code I added to mondrian.rolap.SqlStatement to record every SQL statement executed by Mondrian, and its results, as a JSON document.

SqlStatement.java

// In the SqlStatement class
    private static FileWriter fw;
    private static PrintWriter pw;
    private static Set<String> statements = new HashSet<String>();

    static {
        try {
            fw = new FileWriter(new File("/tmp/x.sql"));
            pw = new PrintWriter(fw);
        } catch (IOException e) {
            // ignore
        }
    }


// In execute() method

            if (statements.add(sql)) {
                if (statements.size() == 1) {
                    pw.println("{");
                    pw.println("queries: [");
                }
                pw.println("  {");
                pw.println("    \"sql\": " + Util.quoteJavaString(sql) + ",");
                pw.println("    \"columns\": [");

                statement = jdbcConnection.createStatement();
                ResultSet rset = statement.executeQuery(sql);
                final ResultSetMetaData metaData = rset.getMetaData();
                final int columnCount = metaData.getColumnCount();
                List<String> types = new ArrayList<String>();
                for (int i = 0; i < columnCount; i++) {
                    String type = javaType(metaData.getColumnType(i + 1));
                    types.add(type);
                    pw.println("      {\"name\": " + Util.quoteJavaString(metaData.getColumnName(i + 1)) + ", \"type\": \"" + type + "\"},");
                }
                pw.println("    ],");
                pw.println("    \"rows\": [");
                while (rset.next()) {
                    pw.print("      [");
                    for (int i = 0; i < columnCount; i++) {
                        if (i > 0) {
                            pw.print(", ");
                        }
                        final String string = rset.getString(i + 1);
                        if (types.get(i).equals("String")) {
                            pw.print(Util.quoteJavaString(string));
                        } else {
                            pw.print(string);
                        }
                    }
                    pw.println("],");
                }
                pw.println("    ]");
                rset.close();
                statement.close();
                pw.println("  },");
                pw.flush();
            }

// New method

    private String javaType(int columnType) throws SQLException {
        switch (columnType) {
        case Types.INTEGER:
            return "int";
        case Types.SMALLINT:
            return "short";
        case Types.VARCHAR:
            return "String";
        case Types.DECIMAL:
            return "BigDecimal";
        case Types.BIT:
            return "boolean";
        case Types.BIGINT:
            return "long";
        default:
            throw new AssertionError("unknown type" + columnType);
        }
    }