//---------------------------------------------------------------------------
//	Greenplum Database
//	Copyright (C) 2012 Greenplum, Inc.
//
//	@filename:
//		CGPOptimizer.cpp
//
//	@doc:
//		Entry point to GP optimizer
//
//	@test:
//
//
//---------------------------------------------------------------------------

#include "gpopt/CGPOptimizer.h"

#include "gpopt/utils/CMemoryPoolPalloc.h"
#include "gpopt/utils/CMemoryPoolPallocManager.h"
#include "gpopt/utils/COptTasks.h"

// the following headers are needed to reference optimizer library initializers
#include "gpos/_api.h"
#include "gpos/memory/CMemoryPoolManager.h"

#include "gpopt/gpdbwrappers.h"
#include "gpopt/init.h"
#include "naucrates/exception.h"
#include "naucrates/init.h"
#include "naucrates/statistics/CFilterStatsProcessor.h"

#include "utils/guc.h"
#include "utils/memutils.h"

extern MemoryContext MessageContext;

//---------------------------------------------------------------------------
//	@function:
//		CGPOptimizer::PlstmtOptimize
//
//	@doc:
//		Optimize given query using GP optimizer
//
//---------------------------------------------------------------------------
PlannedStmt *
CGPOptimizer::GPOPTOptimizedPlan(
	Query *query,
	bool *had_unexpected_failure,
	bool trace_fallback)
{
	SOptContext gpopt_context;
	PlannedStmt *plStmt = nullptr;

	*had_unexpected_failure = false;

	GPOS_TRY
	{
		plStmt = COptTasks::GPOPTOptimizedPlan(query, &gpopt_context);
		// clean up context
		gpopt_context.Free(gpopt_context.epinQuery, gpopt_context.epinPlStmt);
	}
	GPOS_CATCH_EX(ex)
	{
		// clone the error message before context free.
		BOOL clone_failed = false;
		CHAR *serialized_error_msg =
			gpopt_context.CloneErrorMsg(MessageContext, &clone_failed);
		// clean up context
		gpopt_context.Free(gpopt_context.epinQuery, gpopt_context.epinPlStmt);

		// Special handler for a few common user-facing errors. In particular,
		// we want to use the correct error code for these, in case an application
		// tries to do something smart with them.

		if (clone_failed || GPOS_MATCH_EX(ex, gpdxl::ExmaGPDB, gpdxl::ExmiGPDBError))
		{
			PG_RE_THROW();
		}
		else if (GPOS_MATCH_EX(ex, CException::ExmaInvalid,
							   CException::ExmiORCAInvalidState))
		{
			// The fallback logic below cannot be used because the current 
			// exception stack does not belong to the current QUERY.
			if (errstart(LOG, TEXTDOMAIN))
			{
				errcode(ERRCODE_INTERNAL_ERROR);
				errmsg(
					"Worker is already registered! This is an invalid state, please report this error. ");
				errfinish(ex.Filename(), ex.Line(), nullptr);
			}
			GPOS_RESET_EX;
		}

		// Failed to produce a plan, but it wasn't an error that should
		// be propagated to the user. Log the failure if needed, and
		// return without a plan. The caller should fall back to the
		// Postgres planner.

		if (trace_fallback)
		{
			if (errstart(INFO, TEXTDOMAIN))
			{
				errcode(ERRCODE_FEATURE_NOT_SUPPORTED);
				errmsg("pg_orca: falling back to standard planner");
				if (serialized_error_msg)
					errdetail("%s", serialized_error_msg);
				errfinish(ex.Filename(), ex.Line(), nullptr);
			}
		}

		*had_unexpected_failure = gpopt_context.m_is_unexpected_failure;

		if (serialized_error_msg)
		{
			pfree(serialized_error_msg);
		}
	}
	GPOS_CATCH_END;
	return plStmt;
}


//---------------------------------------------------------------------------
//	@function:
//		CGPOptimizer::SerializeDXLPlan
//
//	@doc:
//		Serialize planned statement into DXL
//
//---------------------------------------------------------------------------
char *
CGPOptimizer::SerializeDXLPlan(Query *query)
{
	GPOS_TRY;
	{
		return COptTasks::Optimize(query);
	}
	GPOS_CATCH_EX(ex);
	{
		if (errstart(ERROR, TEXTDOMAIN))
		{
			errcode(ERRCODE_INTERNAL_ERROR);
			errmsg("optimizer failed to produce plan");
			errfinish(ex.Filename(), ex.Line(), nullptr);
		}
	}
	GPOS_CATCH_END;
	return nullptr;
}

//---------------------------------------------------------------------------
//	@function:
//		InitGPOPT()
//
//	@doc:
//		Initialize GPTOPT and dependent libraries
//
//---------------------------------------------------------------------------
void
CGPOptimizer::InitGPOPT()
{
	/* Always use palloc allocators in extension mode */
	CMemoryPoolPallocManager::Init();

	struct gpos_init_params params = {gpdb::IsAbortRequested};

	gpos_init(&params);
	gpdxl_init();
	gpopt_init();

	// Wire the encoding-aware LIKE matcher (PG's textlike) into the ORCA
	// statistics layer so histogram_selectivity-style estimation walks
	// characters instead of raw bytes.
	gpnaucrates::CFilterStatsProcessor::SetLikeMatchFn(&gpdb::TextLikeMatch);
}

//---------------------------------------------------------------------------
//	@function:
//		TerminateGPOPT()
//
//	@doc:
//		Terminate GPOPT and dependent libraries
//
//---------------------------------------------------------------------------
void
CGPOptimizer::TerminateGPOPT()
{
	gpopt_terminate();
	gpdxl_terminate();
	gpos_terminate();
}

//---------------------------------------------------------------------------
//	@function:
//		GPOPTOptimizedPlan
//
//	@doc:
//		Expose GP optimizer API to C files
//
//---------------------------------------------------------------------------
extern "C" {
PlannedStmt *
GPOPTOptimizedPlan(Query *query, bool *had_unexpected_failure, bool trace_fallback)
{
	return CGPOptimizer::GPOPTOptimizedPlan(query, had_unexpected_failure,
											trace_fallback);
}
}

//---------------------------------------------------------------------------
//	@function:
//		SerializeDXLPlan
//
//	@doc:
//		Serialize planned statement to DXL
//
//---------------------------------------------------------------------------
extern "C" {
char *
SerializeDXLPlan(Query *query)
{
	return CGPOptimizer::SerializeDXLPlan(query);
}
}

//---------------------------------------------------------------------------
//	@function:
//		InitGPOPT()
//
//	@doc:
//		Initialize GPTOPT and dependent libraries
//
//---------------------------------------------------------------------------
extern "C" {
void
InitGPOPT()
{
	GPOS_TRY
	{
		try
		{
			CGPOptimizer::InitGPOPT();
		}
		catch (CException ex)
		{
			throw ex;
		}
		catch (...)
		{
			// unexpected failure
			GPOS_RAISE(CException::ExmaUnhandled, CException::ExmiUnhandled);
		}
	}
	GPOS_CATCH_EX(ex)
	{
		if (GPOS_MATCH_EX(ex, gpdxl::ExmaGPDB, gpdxl::ExmiGPDBError))
		{
			PG_RE_THROW();
		}

		if (errstart(ERROR, TEXTDOMAIN))
		{
			errcode(ERRCODE_INTERNAL_ERROR);
			errmsg("optimizer failed to init");
			errfinish(ex.Filename(), ex.Line(), nullptr);
		}
	}
	GPOS_CATCH_END;
}
}

//---------------------------------------------------------------------------
//	@function:
//		TerminateGPOPT()
//
//	@doc:
//		Terminate GPOPT and dependent libraries
//
//---------------------------------------------------------------------------
extern "C" {
void
TerminateGPOPT()
{
	GPOS_TRY
	{
		return CGPOptimizer::TerminateGPOPT();
	}
	GPOS_CATCH_EX(ex)
	{
		if (GPOS_MATCH_EX(ex, gpdxl::ExmaGPDB, gpdxl::ExmiGPDBError))
		{
			PG_RE_THROW();
		}
	}
	GPOS_CATCH_END;
}
}

// EOF