kangpinghuang commented on a change in pull request #1341: Add plain page
URL: https://github.com/apache/incubator-doris/pull/1341#discussion_r295880717
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File path: be/src/olap/rowset/segment_v2/plain_page.h
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@@ -0,0 +1,170 @@
+#pragma once
+
+#include "util/coding.h"
+#include "util/faststring.h"
+#include "olap/olap_common.h"
+#include "olap/types.h"
+#include "olap/rowset/segment_v2/page_builder.h"
+#include "olap/rowset/segment_v2/page_decoder.h"
+#include "olap/rowset/segment_v2/options.h"
+
+namespace doris {
+
+namespace segment_v2 {
+
+static const size_t plainPageHeaderSize = sizeof(uint32_t) * 2;
+
+template<FieldType Type>
+class PlainPageBuilder : public PageBuilder {
+public:
+ PlainPageBuilder(const PageBuilderOptions *options) :
+ _options(options) {
+ // Reserve enough space for the block, plus a bit of slop since
+ // we often overrun the block by a few values.
+ _buffer.reserve(plainPageHeaderSize + _options->data_page_size + 1024);
+ reset();
+ }
+
+ bool is_page_full() override {
+ return _buffer.size() > _options->data_page_size;
+ }
+
+ Status add(const uint8_t *vals, size_t *count) override {
+ size_t old_size = _buffer.size();
+ _buffer.resize(old_size + *count * SIZE_OF_TYPE);
+ memcpy(&_buffer[old_size], vals, *count * SIZE_OF_TYPE);
+ _count += *count;
+ return Status::OK();
+ }
+
+ Status get_dictionary_page(Slice *dictionary_page) override {
+ return Status::NotSupported("get_dictionary_page not supported in
plain page builder");
+ }
+
+ Slice finish(const rowid_t page_first_rowid) override {
+ encode_fixed32_le((uint8_t *) &_buffer[0], _count);
+ encode_fixed32_le((uint8_t *) &_buffer[4], page_first_rowid);
+ return Slice(_buffer.data(), plainPageHeaderSize + _count *
SIZE_OF_TYPE);
+ }
+
+ void reset() override {
+ _count = 0;
+ _buffer.clear();
+ _buffer.resize(plainPageHeaderSize);
+ }
+
+ size_t count() const {
+ return _count;
+ }
+
+ // this api will release the memory ownership of encoded data
+ // Note:
+ // release() should be called after finish
+ // reset() should be called after this function before reuse the
builder
+ void release() override {
+ uint8_t *ret = _buffer.release();
+ (void) ret;
+ }
+
+private:
+ faststring _buffer;
+ const PageBuilderOptions *_options;
+ size_t _count;
+ typedef typename TypeTraits<Type>::CppType CppType;
+ enum {
+ SIZE_OF_TYPE = TypeTraits<Type>::size
+ };
+};
+
+
+template<FieldType Type>
+class PlainPageDecoder : public PageDecoder {
+public:
+ PlainPageDecoder(Slice data) : _data(data),
+ _parsed(false),
+ _num_elems(0),
+ _page_first_ordinal(0),
+ _cur_idx(0) { }
+
+ Status init() override {
+ CHECK(!_parsed);
+
+ if (_data.size < plainPageHeaderSize) {
+ std::stringstream ss;
+ ss << "file corrupton: not enough bytes for header in
PlainBlockDecoder ."
+ "invalid data size:" << _data.size << ", header size:" <<
plainPageHeaderSize;
+ return Status::InternalError(ss.str());
+ }
+
+ _num_elems = decode_fixed32_le((const uint8_t *) &_data[0]);
+ _page_first_ordinal = decode_fixed32_le((const uint8_t *) &_data[4]);
+
+ if (_data.size != plainPageHeaderSize + _num_elems * SIZE_OF_TYPE) {
+ std::stringstream ss;
+ ss << "file corrupton: unexpected data size.";
+ return Status::InternalError(ss.str());
+ }
+
+ _parsed = true;
+
+ seek_to_position_in_page(0);
+ return Status::OK();
+ }
+
+ Status seek_to_position_in_page(size_t pos) override {
+ CHECK(_parsed) << "Must call init()";
+
+ if (PREDICT_FALSE(_num_elems == 0)) {
+ DCHECK_EQ(0, pos);
+ return Status::InternalError("invalid pos");
+ }
+
+ DCHECK_LE(pos, _num_elems);
+
+ _cur_idx = pos;
+ return Status::OK();
+ }
+
+ Status next_batch(size_t *n, ColumnVectorView *dst) override {
+ DCHECK(_parsed);
+
+ if (PREDICT_FALSE(*n == 0 || _cur_idx >= _num_elems)) {
+ *n = 0;
+ return Status::OK();
+ }
+
+ size_t max_fetch = std::min(*n, static_cast<size_t>(_num_elems -
_cur_idx));
+ memcpy(dst->column_vector()->col_data(),
Review comment:
should consider row_offset in ColumnVectorView here.
And How to process string and binary values?
It seems that you should store value length for string or binary data?
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