ClickHouse/dbms/src/Storages/System/StorageSystemPartsBase.cpp

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#include <Storages/ColumnsDescription.h>
#include <Storages/System/StorageSystemPartsBase.h>
#include <Common/escapeForFileName.h>
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/DataTypeDateTime.h>
#include <DataTypes/DataTypeDate.h>
#include <DataStreams/OneBlockInputStream.h>
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#include <Storages/MergeTree/MergeTreeData.h>
#include <Storages/VirtualColumnUtils.h>
#include <Databases/IDatabase.h>
#include <Parsers/queryToString.h>
#include <Parsers/ASTIdentifier.h>
namespace DB
{
bool StorageSystemPartsBase::hasStateColumn(const Names & column_names)
{
bool has_state_column = false;
Names real_column_names;
for (const String & column_name : column_names)
{
if (column_name == "_state")
has_state_column = true;
else
real_column_names.emplace_back(column_name);
}
/// Do not check if only _state column is requested
if (!(has_state_column && real_column_names.empty()))
check(real_column_names);
return has_state_column;
}
class StoragesInfoStream
{
public:
StoragesInfoStream(const SelectQueryInfo & query_info, const Context & context, bool has_state_column)
: query_id(context.getCurrentQueryId())
, has_state_column(has_state_column)
{
/// Will apply WHERE to subset of columns and then add more columns.
/// This is kind of complicated, but we use WHERE to do less work.
Block block_to_filter;
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MutableColumnPtr table_column_mut = ColumnString::create();
MutableColumnPtr engine_column_mut = ColumnString::create();
MutableColumnPtr active_column_mut = ColumnUInt8::create();
{
Databases databases = context.getDatabases();
/// Add column 'database'.
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MutableColumnPtr database_column_mut = ColumnString::create();
for (const auto & database : databases)
{
if (context.hasDatabaseAccessRights(database.first))
database_column_mut->insert(database.first);
}
block_to_filter.insert(ColumnWithTypeAndName(
std::move(database_column_mut), std::make_shared<DataTypeString>(), "database"));
/// Filter block_to_filter with column 'database'.
VirtualColumnUtils::filterBlockWithQuery(query_info.query, block_to_filter, context);
rows = block_to_filter.rows();
/// Block contains new columns, update database_column.
ColumnPtr database_column_ = block_to_filter.getByName("database").column;
if (rows)
{
/// Add columns 'table', 'engine', 'active'
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IColumn::Offsets offsets(rows);
for (size_t i = 0; i < rows; ++i)
{
String database_name = (*database_column_)[i].get<String>();
const DatabasePtr database = databases.at(database_name);
offsets[i] = i ? offsets[i - 1] : 0;
for (auto iterator = database->getIterator(context); iterator->isValid(); iterator->next())
{
String table_name = iterator->name();
StoragePtr storage = iterator->table();
String engine_name = storage->getName();
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if (!dynamic_cast<MergeTreeData *>(storage.get()))
continue;
storages[std::make_pair(database_name, iterator->name())] = storage;
/// Add all combinations of flag 'active'.
for (UInt64 active : {0, 1})
{
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table_column_mut->insert(table_name);
engine_column_mut->insert(engine_name);
active_column_mut->insert(active);
}
offsets[i] += 2;
}
}
for (size_t i = 0; i < block_to_filter.columns(); ++i)
{
ColumnPtr & column = block_to_filter.safeGetByPosition(i).column;
column = column->replicate(offsets);
}
}
}
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block_to_filter.insert(ColumnWithTypeAndName(std::move(table_column_mut), std::make_shared<DataTypeString>(), "table"));
block_to_filter.insert(ColumnWithTypeAndName(std::move(engine_column_mut), std::make_shared<DataTypeString>(), "engine"));
block_to_filter.insert(ColumnWithTypeAndName(std::move(active_column_mut), std::make_shared<DataTypeUInt8>(), "active"));
if (rows)
{
/// Filter block_to_filter with columns 'database', 'table', 'engine', 'active'.
VirtualColumnUtils::filterBlockWithQuery(query_info.query, block_to_filter, context);
rows = block_to_filter.rows();
}
database_column = block_to_filter.getByName("database").column;
table_column = block_to_filter.getByName("table").column;
active_column = block_to_filter.getByName("active").column;
next_row = 0;
}
StorageSystemPartsBase::StoragesInfo next()
{
StorageSystemPartsBase::StoragesInfo info;
info.storage = nullptr;
while (next_row < rows)
{
info.database = (*database_column)[next_row].get<String>();
info.table = (*table_column)[next_row].get<String>();
auto isSameTable = [&info, this] (size_t row) -> bool
{
return (*database_column)[row].get<String>() == info.database &&
(*table_column)[row].get<String>() == info.table;
};
/// What 'active' value we need.
bool need[2]{}; /// [active]
for (; next_row < rows && isSameTable(next_row); ++next_row)
{
bool active = (*active_column)[next_row].get<UInt64>() != 0;
need[active] = true;
}
info.storage = storages.at(std::make_pair(info.database, info.table));
try
{
/// For table not to be dropped and set of columns to remain constant.
info.table_lock = info.storage->lockStructureForShare(false, query_id);
}
catch (const Exception & e)
{
/** There are case when IStorage::drop was called,
* but we still own the object.
* Then table will throw exception at attempt to lock it.
* Just skip the table.
*/
if (e.code() == ErrorCodes::TABLE_IS_DROPPED)
continue;
throw;
}
info.engine = info.storage->getName();
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info.data = dynamic_cast<MergeTreeData *>(info.storage.get());
if (!info.data)
throw Exception("Unknown engine " + info.engine, ErrorCodes::LOGICAL_ERROR);
using State = MergeTreeDataPart::State;
auto & all_parts_state = info.all_parts_state;
auto & all_parts = info.all_parts;
if (need[0])
{
/// If has_state_column is requested, return all states.
if (!has_state_column)
all_parts = info.data->getDataPartsVector({State::Committed, State::Outdated}, &all_parts_state);
else
all_parts = info.data->getAllDataPartsVector(&all_parts_state);
}
else
all_parts = info.data->getDataPartsVector({State::Committed}, &all_parts_state);
break;
}
return info;
}
private:
String query_id;
bool has_state_column;
ColumnPtr database_column;
ColumnPtr table_column;
ColumnPtr active_column;
size_t next_row;
size_t rows;
using StoragesMap = std::map<std::pair<String, String>, StoragePtr>;
StoragesMap storages;
};
BlockInputStreams StorageSystemPartsBase::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*/)
{
bool has_state_column = hasStateColumn(column_names);
StoragesInfoStream stream(query_info, context, has_state_column);
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/// Create the result.
MutableColumns res_columns = getSampleBlock().cloneEmptyColumns();
if (has_state_column)
res_columns.push_back(ColumnString::create());
while (StoragesInfo info = stream.next())
{
processNextStorage(res_columns, info, has_state_column);
}
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Block block = getSampleBlock();
if (has_state_column)
block.insert(ColumnWithTypeAndName(std::make_shared<DataTypeString>(), "_state"));
return BlockInputStreams(1, std::make_shared<OneBlockInputStream>(block.cloneWithColumns(std::move(res_columns))));
}
NameAndTypePair StorageSystemPartsBase::getColumn(const String & column_name) const
{
if (column_name == "_state")
return NameAndTypePair("_state", std::make_shared<DataTypeString>());
return IStorage::getColumn(column_name);
}
bool StorageSystemPartsBase::hasColumn(const String & column_name) const
{
if (column_name == "_state")
return true;
return IStorage::hasColumn(column_name);
}
StorageSystemPartsBase::StorageSystemPartsBase(std::string name_, NamesAndTypesList && columns_)
: name(std::move(name_))
{
ColumnsDescription columns(std::move(columns_));
auto add_alias = [&](const String & alias_name, const String & column_name)
{
ColumnDescription column(alias_name, columns.get(column_name).type);
column.default_desc.kind = ColumnDefaultKind::Alias;
column.default_desc.expression = std::make_shared<ASTIdentifier>(column_name);
columns.add(column);
};
/// Add aliases for old column names for backwards compatibility.
add_alias("bytes", "bytes_on_disk");
add_alias("marks_size", "marks_bytes");
setColumns(columns);
}
}