ClickHouse/src/Interpreters/IInterpreterUnionOrSelectQuery.h

64 lines
2.5 KiB
C++

#pragma once
#include <Interpreters/Context.h>
#include <Interpreters/IInterpreter.h>
#include <Interpreters/SelectQueryOptions.h>
#include <Parsers/IAST_fwd.h>
#include <DataTypes/DataTypesNumber.h>
namespace DB
{
class IInterpreterUnionOrSelectQuery : public IInterpreter
{
public:
IInterpreterUnionOrSelectQuery(const ASTPtr & query_ptr_, ContextPtr context_, const SelectQueryOptions & options_)
: query_ptr(query_ptr_)
, context(Context::createCopy(context_))
, options(options_)
, max_streams(context->getSettingsRef().max_threads)
{
if (options.shard_num)
context->addLocalScalar(
"_shard_num",
Block{{DataTypeUInt32().createColumnConst(1, *options.shard_num), std::make_shared<DataTypeUInt32>(), "_shard_num"}});
if (options.shard_count)
context->addLocalScalar(
"_shard_count",
Block{{DataTypeUInt32().createColumnConst(1, *options.shard_count), std::make_shared<DataTypeUInt32>(), "_shard_count"}});
}
virtual void buildQueryPlan(QueryPlan & query_plan) = 0;
QueryPipelineBuilder buildQueryPipeline();
virtual void ignoreWithTotals() = 0;
virtual ~IInterpreterUnionOrSelectQuery() override = default;
Block getSampleBlock() { return result_header; }
size_t getMaxStreams() const { return max_streams; }
void extendQueryLogElemImpl(QueryLogElement & elem, const ASTPtr &, ContextPtr) const override;
/// Returns whether the query uses the view source from the Context
/// The view source is a virtual storage that currently only materialized views use to replace the source table
/// with the incoming block only
/// This flag is useful to know for how long we can cache scalars generated by this query: If it doesn't use the virtual storage
/// then we can cache the scalars forever (for any query that doesn't use the virtual storage either), but if it does use the virtual
/// storage then we can only keep the scalar result around while we are working with that source block
/// You can find more details about this under ExecuteScalarSubqueriesMatcher::visit
bool usesViewSource() { return uses_view_source; }
protected:
ASTPtr query_ptr;
ContextMutablePtr context;
Block result_header;
SelectQueryOptions options;
size_t max_streams = 1;
bool settings_limit_offset_needed = false;
bool settings_limit_offset_done = false;
bool uses_view_source = false;
};
}