public static List genSplitSqlForOracle()

in plugin-rdbms-util/src/main/java/com/alibaba/datax/plugin/rdbms/reader/util/SingleTableSplitUtil.java [317:412]
89 lines of code
14 McCabe index (conditional complexity)

    public static List<String> genSplitSqlForOracle(String splitPK,
            String table, String where, Configuration configuration,
            int adviceNum) {
        if (adviceNum < 1) {
            throw new IllegalArgumentException(String.format(
                    "切分份数不能小于1. 此处:adviceNum=[%s].", adviceNum));
        } else if (adviceNum == 1) {
            return null;
        }
        String whereSql = String.format("%s IS NOT NULL", splitPK);
        if (StringUtils.isNotBlank(where)) {
            whereSql = String.format(" WHERE (%s) AND (%s) ", whereSql, where);
        } else {
            whereSql = String.format(" WHERE (%s) ", whereSql);
        }
        Double percentage = configuration.getDouble(Key.SAMPLE_PERCENTAGE, 0.1);
        String sampleSqlTemplate = "SELECT * FROM ( SELECT %s FROM %s SAMPLE (%s) %s ORDER BY DBMS_RANDOM.VALUE) WHERE ROWNUM <= %s ORDER by %s ASC";
        String splitSql = String.format(sampleSqlTemplate, splitPK, table,
                percentage, whereSql, adviceNum, splitPK);

        int fetchSize = configuration.getInt(Constant.FETCH_SIZE, 32);
        String jdbcURL = configuration.getString(Key.JDBC_URL);
        String username = configuration.getString(Key.USERNAME);
        String password = configuration.getString(Key.PASSWORD);
        Connection conn = DBUtil.getConnection(DATABASE_TYPE, jdbcURL,
                username, password);
        LOG.info("split pk [sql={}] is running... ", splitSql);
        ResultSet rs = null;
        List<Pair<Object, Integer>> splitedRange = new ArrayList<Pair<Object, Integer>>();
        try {
            try {
                rs = DBUtil.query(conn, splitSql, fetchSize);
            } catch (Exception e) {
                throw RdbmsException.asQueryException(DATABASE_TYPE, e,
                        splitSql, table, username);
            }
            if (configuration != null) {
                configuration
                        .set(Constant.PK_TYPE, Constant.PK_TYPE_MONTECARLO);
            }
            ResultSetMetaData rsMetaData = rs.getMetaData();
            while (DBUtil.asyncResultSetNext(rs)) {
                ImmutablePair<Object, Integer> eachPoint = new ImmutablePair<Object, Integer>(
                        rs.getObject(1), rsMetaData.getColumnType(1));
                splitedRange.add(eachPoint);
            }
        } catch (DataXException e) {
            throw e;
        } catch (Exception e) {
            throw DataXException.asDataXException(
                    DBUtilErrorCode.ILLEGAL_SPLIT_PK,
                    "DataX尝试切分表发生错误. 请检查您的配置并作出修改.", e);
        } finally {
            DBUtil.closeDBResources(rs, null, null);
        }
        LOG.debug(JSON.toJSONString(splitedRange));
        List<String> rangeSql = new ArrayList<String>();
        int splitedRangeSize = splitedRange.size();
        // warn: splitedRangeSize may be 0 or 1，切分规则为IS NULL以及 IS NOT NULL
        // demo: Parameter rangeResult can not be null and its length can not <2. detail:rangeResult=[24999930].
        if (splitedRangeSize >= 2) {
            // warn: oracle Number is long type here
            if (isLongType(splitedRange.get(0).getRight())) {
                BigInteger[] integerPoints = new BigInteger[splitedRange.size()];
                for (int i = 0; i < splitedRangeSize; i++) {
                    integerPoints[i] = new BigInteger(splitedRange.get(i)
                            .getLeft().toString());
                }
                rangeSql.addAll(RdbmsRangeSplitWrap.wrapRange(integerPoints,
                        splitPK));
                // its ok if splitedRangeSize is 1
                rangeSql.add(RdbmsRangeSplitWrap.wrapFirstLastPoint(
                        integerPoints[0], integerPoints[splitedRangeSize - 1],
                        splitPK));
            } else if (isStringType(splitedRange.get(0).getRight())) {
                // warn: treated as string type
                String[] stringPoints = new String[splitedRange.size()];
                for (int i = 0; i < splitedRangeSize; i++) {
                    stringPoints[i] = new String(splitedRange.get(i).getLeft()
                            .toString());
                }
                rangeSql.addAll(RdbmsRangeSplitWrap.wrapRange(stringPoints,
                        splitPK, "'", DATABASE_TYPE));
                // its ok if splitedRangeSize is 1
                rangeSql.add(RdbmsRangeSplitWrap.wrapFirstLastPoint(
                        stringPoints[0], stringPoints[splitedRangeSize - 1],
                        splitPK, "'", DATABASE_TYPE));
            } else {
                throw DataXException
                        .asDataXException(
                                DBUtilErrorCode.ILLEGAL_SPLIT_PK,
                                "您配置的DataX切分主键(splitPk)有误. 因为您配置的切分主键(splitPk) 类型 DataX 不支持. DataX 仅支持切分主键为一个,并且类型为整数或者字符串类型. 请尝试使用其他的切分主键或者联系 DBA 进行处理.");
            }
        }
        return rangeSql;
    }