ClickHouse/dbms/src/Storages/StorageChunkRef.cpp
2013-10-26 03:20:51 +00:00

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#include <DB/Parsers/ASTCreateQuery.h>
#include <DB/Parsers/ASTIdentifier.h>
#include <DB/Storages/StorageChunkRef.h>
namespace DB
{
StoragePtr StorageChunkRef::create(const std::string & name_, const Context & context_, const std::string & source_database_name_, const std::string & source_table_name_, bool attach)
{
return (new StorageChunkRef(name_, context_, source_database_name_, source_table_name_, attach))->thisPtr();
}
BlockInputStreams StorageChunkRef::read(
const Names & column_names,
ASTPtr query,
const Settings & settings,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size,
unsigned threads)
{
return getSource().readFromChunk(name, column_names, query, settings, processed_stage, max_block_size, threads);
}
ASTPtr StorageChunkRef::getCustomCreateQuery(const Context & context) const
{
/// Берём CREATE запрос для таблицы, на которую эта ссылается, и меняем в ней имя и движок.
ASTPtr res = context.getCreateQuery(source_database_name, source_table_name);
ASTCreateQuery & res_create = dynamic_cast<ASTCreateQuery &>(*res);
res_create.database.clear();
res_create.table = name;
res_create.storage = new ASTFunction;
ASTFunction & storage_ast = static_cast<ASTFunction &>(*res_create.storage);
storage_ast.name = "ChunkRef";
storage_ast.arguments = new ASTExpressionList;
storage_ast.children.push_back(storage_ast.arguments);
ASTExpressionList & args_ast = static_cast<ASTExpressionList &>(*storage_ast.arguments);
args_ast.children.push_back(new ASTIdentifier(StringRange(), source_database_name, ASTIdentifier::Database));
args_ast.children.push_back(new ASTIdentifier(StringRange(), source_table_name, ASTIdentifier::Table));
return res;
}
void StorageChunkRef::dropImpl()
{
try
{
getSource().removeReference();
}
catch (const Exception & e)
{
if (e.code() != ErrorCodes::UNKNOWN_TABLE)
throw;
LOG_ERROR(&Logger::get("StorageChunkRef"), e.displayText());
/// Если таблицы с данными не существует - дополнительных действий при удалении не требуется.
}
}
StorageChunkRef::StorageChunkRef(const std::string & name_, const Context & context_, const std::string & source_database_name_, const std::string & source_table_name_, bool attach)
: source_database_name(source_database_name_), source_table_name(source_table_name_), name(name_), context(context_)
{
if (!attach)
getSource().addReference();
}
StorageChunks & StorageChunkRef::getSource()
{
return dynamic_cast<StorageChunks &>(*context.getTable(source_database_name, source_table_name));
}
const StorageChunks & StorageChunkRef::getSource() const
{
const StoragePtr table_ptr = context.getTable(source_database_name, source_table_name);
const StorageChunks * chunks = dynamic_cast<const StorageChunks *>(&*table_ptr);
if (chunks == NULL)
throw Exception("Referenced table " + source_table_name + " in database " + source_database_name + " doesn't exist", ErrorCodes::UNKNOWN_TABLE);
return *chunks;
}
}