hybridse::vm::Engine

#include <engine.h>

An engine is responsible to compile SQL on the specific Catalog.

Summary

class hybridse::vm::Engine;

An engine is responsible to compile SQL on the specific Catalog.

An engine can be used to `compile sql and explain the compiling result. It maintains a LRU cache for compiling result.

Example

// Assuming the catalog has been created and initialized before
base::Status status;
EngineOptions options;
Engine engine(catalog, options);
BatchRunSession session;
std::db = "test_db";
std::string sql = "select col0, col1, col2, col1+col2 as col12 from t1;";
engine.Get(sql, db, session, status);
engine.Explain(sql, db, EngineMode::kBatchMode, &output, &status);

Public functions
Engine(const std::shared_ptr< Catalog > & cl)	Create an Engine with a specific Catalog object.
Engine(const std::shared_ptr< Catalog > & cl, const EngineOptions & options)	Create an Engine a specific Catalog object, configuring it with EngineOptions.
~Engine()
Get(const std::string & sql, const std::string & db, RunSession & session, base::Status & status)	bool Compile sql in db and stored the results in the session.
GetDependentTables(const std::string & sql, const std::string & db, EngineMode engine_mode, std::set< std::string > * tables, base::Status & status)	bool Search all tables related to the specific sql in db.
Explain(const std::string & sql, const std::string & db, EngineMode engine_mode, ExplainOutput * explain_output, base::Status * status)	bool Explain sql compiling result.
Explain(const std::string & sql, const std::string & db, EngineMode engine_mode, const std::set< size_t > & common_column_indices, ExplainOutput * explain_output, base::Status * status)	bool Same as above, but allowing compiling with configuring common column indices.
UpdateCatalog(std::shared_ptr< Catalog > cl)	void Update engine's catalog.
ClearCacheLocked(const std::string & db)	void Clear engine's compiling result cache.
InitializeGlobalLLVM()	void Initialize LLVM environments.

Public Functions

function Engine

explicit Engine(
    const std::shared_ptr< Catalog > & cl
)

Create an Engine with a specific Catalog object.

function Engine

Engine(
    const std::shared_ptr< Catalog > & cl,
    const EngineOptions & options
)

Create an Engine a specific Catalog object, configuring it with EngineOptions.

function ~Engine

~Engine()

function Get

bool Get(
    const std::string & sql,
    const std::string & db,
    RunSession & session,
    base::Status & status
)

Compile sql in db and stored the results in the session.

function GetDependentTables

bool GetDependentTables(
    const std::string & sql,
    const std::string & db,
    EngineMode engine_mode,
    std::set< std::string > * tables,
    base::Status & status
)

Search all tables related to the specific sql in db.

The tables' names are returned in tables

function Explain

bool Explain(
    const std::string & sql,
    const std::string & db,
    EngineMode engine_mode,
    ExplainOutput * explain_output,
    base::Status * status
)

Explain sql compiling result.

The results are returned as ExplainOutput in explain_output. The success or fail status message is returned as Status in status. TODO: base::Status* status -> base::Status& status

function Explain

bool Explain(
    const std::string & sql,
    const std::string & db,
    EngineMode engine_mode,
    const std::set< size_t > & common_column_indices,
    ExplainOutput * explain_output,
    base::Status * status
)

Same as above, but allowing compiling with configuring common column indices.

The common column indices are used for common column optimization under EngineMode::kBatchRequestMode

function UpdateCatalog

inline void UpdateCatalog(
    std::shared_ptr< Catalog > cl
)

Update engine's catalog.

function ClearCacheLocked

void ClearCacheLocked(
    const std::string & db
)

Clear engine's compiling result cache.

function InitializeGlobalLLVM

static void InitializeGlobalLLVM()

Initialize LLVM environments.