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);
}
/** 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);
}
}
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);
}
}
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);
}
}