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Nikolai Kochetov 2019-09-11 13:46:41 +03:00
parent 96f7eb1141
commit 172e4d76d7
1 changed files with 9 additions and 1 deletions
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10
dbms/src/Processors/Transforms/AggregatingTransform.cpp
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@ -14,7 +14,8 @@ namespace ProfileEvents
namespace DB
{
/// Convert block to chunk.
/// Adds additional info about aggregation.
static Chunk convertToChunk(const Block & block)
{
auto info = std::make_shared<AggregatedChunkInfo>();
@ -30,6 +31,7 @@ static Chunk convertToChunk(const Block & block)
namespace
{
/// Reads chunks from file in native format. Provide chunks with aggregation info.
class SourceFromNativeStream : public ISource
{
public:
@ -65,6 +67,8 @@ namespace
};
}
/// Worker which merges buckets for two-level aggregation.
/// Atomically increments bucket counter and returns merged result.
class ConvertingAggregatedToChunksSource : public ISource
{
public:
@ -104,6 +108,10 @@ private:
static constexpr UInt32 NUM_BUCKETS = 256;
};
/// Generates chunks with aggregated data.
/// In single level case, aggregates data itself.
/// In two-level case, creates `ConvertingAggregatedToChunksSource` workers.
/// Result chunks guaranteed to be sorted by bucket number.
class ConvertingAggregatedToChunksTransform : public IProcessor
{
public: