@Override
public boolean next() {
readBuffer.clear();
searchRow = null;
row = null;
index++;
if (result != null && index < result.length) {
setSearchRow();
return true;
}
Transaction transaction = session.getTransaction();
List<KeyValue> kvs;
KeyValue kv;
Result r;
long queryTimestamp;
try {
result = session.getRegionServer().next(scannerId, fetchSize);
ArrayList<Result> list = new ArrayList<Result>(result.length);
for (int i = 0; i < result.length; i++) {
r = result[i];
kvs = r.list();
// 当Result.isEmpty=true时，r.list()也返回null，所以这里不用再判断kvs.isEmpty
if (kvs != null) {
kv = kvs.get(0);
queryTimestamp = kv.getTimestamp();
if (queryTimestamp < transaction.getStartTimestamp() & queryTimestamp % 2 == 0) {
if (kv.getValueLength() != 0) // kv已删除，不需要再处理
list.add(r);
continue;
}
}
// TODO Filter.filter很慢
r = new Result(Filter.filter(session.getRegionServer(), regionName, transaction, kvs, 1));
if (!r.isEmpty()) list.add(r);
}
result = list.toArray(new Result[0]);
} catch (Exception e) {
close();
throw DbException.convert(e);
}
index = 0;
if (result != null && result.length > 0) {
setSearchRow();
return true;
}
close();
return false;
}
private void close() {
try {
session.getRegionServer().close(scannerId);
} catch (IOException e) {
// ignore
}
}
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);
}
}