kangpinghuang commented on a change in pull request #764: Convert next_row
interface to next_block
URL: https://github.com/apache/incubator-doris/pull/764#discussion_r268632037
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File path: be/src/olap/rowset/alpha_rowset_reader.cpp
##########
@@ -51,71 +43,66 @@ OLAPStatus AlphaRowsetReader::init(RowsetReaderContext*
read_context) {
if (_current_read_context->stats != nullptr) {
_stats = _current_read_context->stats;
}
- _dst_cursor = new(std::nothrow)RowCursor();
- _dst_cursor->init(*(_current_read_context->tablet_schema));
- OLAPStatus status = _init_column_datas(read_context);
- return status;
-}
-bool AlphaRowsetReader::has_next() {
- bool next_flag = false;
- for (int i = 0; i < _column_datas.size(); ++i) {
- auto& row_block = _row_blocks[i];
- if (row_block != nullptr) {
- if (row_block->has_remaining()) {
- next_flag = true;
- } else {
- OLAPStatus status = _get_next_block(i, &_row_blocks[i]);
- if (status == OLAP_ERR_DATA_EOF) {
- _row_blocks[i] = nullptr;
- continue;
- } else if (status != OLAP_SUCCESS) {
- LOG(WARNING) << "_get_next_block failed, status:" <<
status;
- return false;
- } else {
- if (_row_blocks[i] != nullptr &&
_row_blocks[i]->has_remaining()) {
- next_flag = true;
- }
- }
- }
+ Version version = _alpha_rowset_meta->version();
+ _is_singleton_rowset = (version.first == version.second);
+ _ordinal = 0;
+ bool merge = false;
+ /*
+ * For singleton rowset, there exists three situations.
+ * 1. QUERY task will set preaggregation.
+ * If preaggregation is set to be true
+ * there is not necessary to merge row in advance.
+ * 2. QEURY task for DUP_KEYS tablet has no necessities
+ * to merge row in advance.
+ * 2. COMPACTION/CHECKSUM/ALTER_TABLET task should merge
+ * row in advance.
+ * For cumulative rowset, there are no necessities to merge row in advance.
+ */
+ RETURN_NOT_OK(_init_merge_ctxs(read_context));
+ if (_is_singleton_rowset && _merge_ctxs.size() > 1) {
+ if (_current_read_context->reader_type == READER_QUERY
+ && _current_read_context->preaggregation) {
+ // 1. QUERY task which set pregaggregation to be true
+ _next_block = &AlphaRowsetReader::_union_block;
+ } else if (_current_read_context->reader_type == READER_QUERY
+ && _current_read_context->tablet_schema->keys_type() ==
DUP_KEYS) {
+ // 2. QUERY task for DUP_KEYS tablet
+ _next_block = &AlphaRowsetReader::_union_block;
+ } else {
+ // 3. COMPACTION/CHECKSUM/ALTER_TABLET task
+ _next_block = &AlphaRowsetReader::_merge_block;
+ merge = true;
}
- }
- return next_flag;
-}
-
-OLAPStatus AlphaRowsetReader::next(RowCursor** row) {
- OLAPStatus status = OLAP_SUCCESS;
- if (_is_cumulative_rowset) {
- status = _get_next_row_for_cumulative_rowset(row);
} else {
- status = _get_next_row_for_singleton_rowset(row);
+ // query task to scan cumulative rowset
+ _next_block = &AlphaRowsetReader::_union_block;
}
- return status;
-}
-OLAPStatus AlphaRowsetReader::next_block(std::shared_ptr<RowBlock> block) {
- block->clear();
- size_t num_rows_in_block = 0;
- while (block->pos() < _num_rows_per_row_block) {
- RowCursor* row_cursor = nullptr;
- OLAPStatus status = next(&row_cursor);
- if (status == OLAP_ERR_DATA_EOF && block->pos() > 0) {
- break;
- } else if (status != OLAP_SUCCESS) {
- LOG(WARNING) << "next block failed.status:" << status;
- return status;
+ if (merge) {
+ _read_block.reset(new (std::nothrow)
RowBlock(_current_read_context->tablet_schema));
+ if (_read_block == nullptr) {
+ LOG(WARNING) << "new row block failed in reader";
+ return OLAP_ERR_MALLOC_ERROR;
+ }
+ RowBlockInfo block_info;
+ block_info.row_num =
_current_read_context->tablet_schema->num_rows_per_row_block();
+ block_info.null_supported = true;
+ _read_block->init(block_info);
+ _dst_cursor = new (std::nothrow) RowCursor();
Review comment:
add if (_dst_cursor == nullptr)
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