ClickHouse/src/Storages/System/StorageSystemDetachedParts.cpp
Alexey Milovidov 03e17405cd Checkpoint
2020-04-22 10:03:43 +03:00

94 lines
3.5 KiB
C++

#include <Storages/System/StorageSystemDetachedParts.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeNullable.h>
#include <DataStreams/OneBlockInputStream.h>
#include <ext/shared_ptr_helper.h>
#include <Storages/IStorage.h>
#include <Storages/System/StorageSystemPartsBase.h>
#include <Processors/Sources/SourceFromSingleChunk.h>
namespace DB
{
/**
* Implements system table 'detached_parts' which allows to get information
* about detached data parts for tables of MergeTree family.
* We don't use StorageSystemPartsBase, because it introduces virtual _state
* column and column aliases which we don't need.
*/
class StorageSystemDetachedParts final :
public ext::shared_ptr_helper<StorageSystemDetachedParts>,
public IStorage
{
friend struct ext::shared_ptr_helper<StorageSystemDetachedParts>;
public:
std::string getName() const override { return "SystemDetachedParts"; }
protected:
explicit StorageSystemDetachedParts()
: IStorage({"system", "detached_parts"})
{
setColumns(ColumnsDescription{{
{"database", std::make_shared<DataTypeString>()},
{"table", std::make_shared<DataTypeString>()},
{"partition_id", std::make_shared<DataTypeNullable>(std::make_shared<DataTypeString>())},
{"name", std::make_shared<DataTypeString>()},
{"disk", std::make_shared<DataTypeString>()},
{"reason", std::make_shared<DataTypeNullable>(std::make_shared<DataTypeString>())},
{"min_block_number", std::make_shared<DataTypeNullable>(std::make_shared<DataTypeInt64>())},
{"max_block_number", std::make_shared<DataTypeNullable>(std::make_shared<DataTypeInt64>())},
{"level", std::make_shared<DataTypeNullable>(std::make_shared<DataTypeUInt32>())}
}});
}
Pipes read(
const Names & /* column_names */,
const SelectQueryInfo & query_info,
const Context & context,
QueryProcessingStage::Enum /*processed_stage*/,
const size_t /*max_block_size*/,
const unsigned /*num_streams*/) override
{
StoragesInfoStream stream(query_info, context);
/// Create the result.
Block block = getSampleBlock();
MutableColumns new_columns = block.cloneEmptyColumns();
while (StoragesInfo info = stream.next())
{
const auto parts = info.data->getDetachedParts();
for (const auto & p : parts)
{
size_t i = 0;
new_columns[i++]->insert(info.database);
new_columns[i++]->insert(info.table);
new_columns[i++]->insert(p.valid_name ? p.partition_id : Field());
new_columns[i++]->insert(p.dir_name);
new_columns[i++]->insert(p.disk);
new_columns[i++]->insert(p.valid_name ? p.prefix : Field());
new_columns[i++]->insert(p.valid_name ? p.min_block : Field());
new_columns[i++]->insert(p.valid_name ? p.max_block : Field());
new_columns[i++]->insert(p.valid_name ? p.level : Field());
}
}
UInt64 num_rows = new_columns.at(0)->size();
Chunk chunk(std::move(new_columns), num_rows);
Pipes pipes;
pipes.emplace_back(std::make_shared<SourceFromSingleChunk>(std::move(block), std::move(chunk)));
return pipes;
}
};
StoragePtr
createDetachedPartsTable()
{
return StorageSystemDetachedParts::create();
}
}