コード例 #1
0
ファイル: SubqueryCursor.java プロジェクト: 4399data/Lealone
 public SubqueryCursor(TableFilter filter, SearchRow first, SearchRow last) {
   StringBuilder buff = new StringBuilder("SELECT * FROM ");
   buff.append(filter.getTable().getSQL());
   Expression filterCondition = filter.getFilterCondition();
   if (filterCondition != null) {
     buff.append(" WHERE ").append(StringUtils.unEnclose(filterCondition.getSQL()));
   }
   Prepared prepared = filter.getSession().prepare(buff.toString(), true);
   subqueryResult = prepared.query(-1);
 }
コード例 #2
0
ファイル: Optimizer.java プロジェクト: 4399data/Lealone
 /** Calculate the best query plan to use. */
 void optimize() {
   calculateBestPlan();
   bestPlan.removeUnusableIndexConditions();
   TableFilter[] f2 = bestPlan.getFilters();
   topFilter = f2[0];
   for (int i = 0; i < f2.length - 1; i++) {
     f2[i].addJoin(f2[i + 1], false, false, null);
   }
   for (TableFilter f : f2) {
     PlanItem item = bestPlan.getItem(f);
     f.setPlanItem(item);
   }
 }
コード例 #3
0
ファイル: Optimizer.java プロジェクト: 4399data/Lealone
 private void calculateBruteForceSome() {
   int bruteForce = getMaxBruteForceFilters(filters.length);
   TableFilter[] list = new TableFilter[filters.length];
   Permutations<TableFilter> p = Permutations.create(filters, list, bruteForce);
   for (int x = 0; !canStop(x) && p.next(); x++) {
     // find out what filters are not used yet
     for (TableFilter f : filters) {
       f.setUsed(false);
     }
     for (int i = 0; i < bruteForce; i++) {
       list[i].setUsed(true);
     }
     // fill the remaining elements with the unused elements (greedy)
     for (int i = bruteForce; i < filters.length; i++) {
       double costPart = -1.0;
       int bestPart = -1;
       for (int j = 0; j < filters.length; j++) {
         if (!filters[j].isUsed()) {
           if (i == filters.length - 1) {
             bestPart = j;
             break;
           }
           list[i] = filters[j];
           Plan part = new Plan(list, i + 1, condition);
           double costNow = part.calculateCost(session);
           if (costPart < 0 || costNow < costPart) {
             costPart = costNow;
             bestPart = j;
           }
         }
       }
       filters[bestPart].setUsed(true);
       list[i] = filters[bestPart];
     }
     testPlan(list);
   }
 }
コード例 #4
0
  public HBaseSecondaryIndexCursor(
      HBaseSecondaryIndex index, TableFilter filter, byte[] startKey, byte[] endKey) {
    defaultColumnFamilyName =
        Bytes.toBytes(((HBaseTable) filter.getTable()).getDefaultColumnFamilyName());
    secondaryIndex = index;
    session = (HBaseSession) filter.getSession();
    Prepared p = filter.getPrepared();
    if (p instanceof WithWhereClause) {
      regionName = Bytes.toBytes(((WithWhereClause) p).getWhereClauseSupport().getRegionName());
    }

    if (regionName == null) throw new RuntimeException("regionName is null");

    fetchSize = filter.getPrepared().getFetchSize();
    // 非查询的操作一般不设置fetchSize,此时fetchSize为0,所以要设置一个默认值
    // if (fetchSize < 1 && !filter.getPrepared().isQuery())
    if (fetchSize < 1) fetchSize = SysProperties.SERVER_RESULT_SET_FETCH_SIZE;

    if (filter.getSelect() != null) columns = filter.getSelect().getColumns(filter);
    else columns = Arrays.asList(filter.getTable().getColumns());

    if (startKey == null) startKey = HConstants.EMPTY_BYTE_ARRAY;
    if (endKey == null) endKey = HConstants.EMPTY_BYTE_ARRAY;

    Scan scan = new Scan();
    scan.setMaxVersions(1);
    try {
      HRegionInfo info = session.getRegionServer().getRegionInfo(regionName);
      if (Bytes.compareTo(startKey, info.getStartKey()) >= 0) scan.setStartRow(startKey);
      else scan.setStartRow(info.getStartKey());

      if (Bytes.equals(endKey, HConstants.EMPTY_BYTE_ARRAY)) scan.setStopRow(info.getEndKey());
      else if (Bytes.compareTo(endKey, info.getEndKey()) < 0) scan.setStopRow(endKey);
      else scan.setStopRow(info.getEndKey());

      scan.addColumn(HBaseSecondaryIndex.PSEUDO_FAMILY, HBaseSecondaryIndex.PSEUDO_COLUMN);

      scannerId = session.getRegionServer().openScanner(regionName, scan);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }