ClickHouse/src/Storages/SelectQueryDescription.cpp
Ivan 495c6e03aa
Replace all Context references with std::weak_ptr (#22297)
* Replace all Context references with std::weak_ptr

* Fix shared context captured by value

* Fix build

* Fix Context with named sessions

* Fix copy context

* Fix gcc build

* Merge with master and fix build

* Fix gcc-9 build
2021-04-11 02:33:54 +03:00

136 lines
4.4 KiB
C++

#include <Storages/SelectQueryDescription.h>
#include <Parsers/ASTSelectWithUnionQuery.h>
#include <Parsers/ASTSelectQuery.h>
#include <Interpreters/getTableExpressions.h>
#include <Interpreters/AddDefaultDatabaseVisitor.h>
#include <Interpreters/Context.h>
namespace DB
{
namespace ErrorCodes
{
extern const int QUERY_IS_NOT_SUPPORTED_IN_MATERIALIZED_VIEW;
extern const int LOGICAL_ERROR;
}
SelectQueryDescription::SelectQueryDescription(const SelectQueryDescription & other)
: select_table_id(other.select_table_id)
, select_query(other.select_query ? other.select_query->clone() : nullptr)
, inner_query(other.inner_query ? other.inner_query->clone() : nullptr)
{
}
SelectQueryDescription & SelectQueryDescription::SelectQueryDescription::operator=(const SelectQueryDescription & other)
{
if (&other == this)
return *this;
select_table_id = other.select_table_id;
if (other.select_query)
select_query = other.select_query->clone();
else
select_query.reset();
if (other.inner_query)
inner_query = other.inner_query->clone();
else
inner_query.reset();
return *this;
}
namespace
{
StorageID extractDependentTableFromSelectQuery(ASTSelectQuery & query, ContextPtr context, bool add_default_db = true)
{
if (add_default_db)
{
AddDefaultDatabaseVisitor visitor(context->getCurrentDatabase(), false, nullptr);
visitor.visit(query);
}
if (auto db_and_table = getDatabaseAndTable(query, 0))
{
return StorageID(db_and_table->database, db_and_table->table/*, db_and_table->uuid*/);
}
else if (auto subquery = extractTableExpression(query, 0))
{
auto * ast_select = subquery->as<ASTSelectWithUnionQuery>();
if (!ast_select)
throw Exception("Logical error while creating StorageMaterializedView. "
"Could not retrieve table name from select query.",
DB::ErrorCodes::LOGICAL_ERROR);
if (ast_select->list_of_selects->children.size() != 1)
throw Exception("UNION is not supported for MATERIALIZED VIEW",
ErrorCodes::QUERY_IS_NOT_SUPPORTED_IN_MATERIALIZED_VIEW);
auto & inner_query = ast_select->list_of_selects->children.at(0);
return extractDependentTableFromSelectQuery(inner_query->as<ASTSelectQuery &>(), context, false);
}
else
return StorageID::createEmpty();
}
void checkAllowedQueries(const ASTSelectQuery & query)
{
if (query.prewhere() || query.final() || query.sampleSize())
throw Exception("MATERIALIZED VIEW cannot have PREWHERE, SAMPLE or FINAL.", DB::ErrorCodes::QUERY_IS_NOT_SUPPORTED_IN_MATERIALIZED_VIEW);
ASTPtr subquery = extractTableExpression(query, 0);
if (!subquery)
return;
if (const auto * ast_select = subquery->as<ASTSelectWithUnionQuery>())
{
if (ast_select->list_of_selects->children.size() != 1)
throw Exception("UNION is not supported for MATERIALIZED VIEW", ErrorCodes::QUERY_IS_NOT_SUPPORTED_IN_MATERIALIZED_VIEW);
const auto & inner_query = ast_select->list_of_selects->children.at(0);
checkAllowedQueries(inner_query->as<ASTSelectQuery &>());
}
}
}
/// check if only one single select query in SelectWithUnionQuery
static bool isSingleSelect(const ASTPtr & select, ASTPtr & res)
{
auto new_select = select->as<ASTSelectWithUnionQuery &>();
if (new_select.list_of_selects->children.size() != 1)
return false;
auto & new_inner_query = new_select.list_of_selects->children.at(0);
if (new_inner_query->as<ASTSelectQuery>())
{
res = new_inner_query;
return true;
}
else
return isSingleSelect(new_inner_query, res);
}
SelectQueryDescription SelectQueryDescription::getSelectQueryFromASTForMatView(const ASTPtr & select, ContextPtr context)
{
ASTPtr new_inner_query;
if (!isSingleSelect(select, new_inner_query))
throw Exception("UNION is not supported for MATERIALIZED VIEW", ErrorCodes::QUERY_IS_NOT_SUPPORTED_IN_MATERIALIZED_VIEW);
auto & select_query = new_inner_query->as<ASTSelectQuery &>();
checkAllowedQueries(select_query);
SelectQueryDescription result;
result.select_table_id = extractDependentTableFromSelectQuery(select_query, context);
result.select_query = select->as<ASTSelectWithUnionQuery &>().clone();
result.inner_query = new_inner_query->clone();
return result;
}
}