ClickHouse/src/Storages/StorageValues.cpp
2021-10-16 17:03:50 +03:00

44 lines
1.2 KiB
C++

#include <Storages/IStorage.h>
#include <Storages/ColumnsDescription.h>
#include <Storages/StorageValues.h>
#include <Processors/Sources/SourceFromSingleChunk.h>
#include <QueryPipeline/Pipe.h>
namespace DB
{
StorageValues::StorageValues(
const StorageID & table_id_,
const ColumnsDescription & columns_,
const Block & res_block_,
const NamesAndTypesList & virtuals_)
: IStorage(table_id_), res_block(res_block_), virtuals(virtuals_)
{
StorageInMemoryMetadata storage_metadata;
storage_metadata.setColumns(columns_);
setInMemoryMetadata(storage_metadata);
}
Pipe StorageValues::read(
const Names & column_names,
const StorageMetadataPtr & metadata_snapshot,
SelectQueryInfo & /*query_info*/,
ContextPtr /*context*/,
QueryProcessingStage::Enum /*processed_stage*/,
size_t /*max_block_size*/,
unsigned /*num_streams*/)
{
metadata_snapshot->check(column_names, getVirtuals(), getStorageID());
/// Get only required columns.
Block block;
for (const auto & name : column_names)
block.insert(res_block.getByName(name));
Chunk chunk(block.getColumns(), block.rows());
return Pipe(std::make_shared<SourceFromSingleChunk>(block.cloneEmpty(), std::move(chunk)));
}
}