/*****************************************************************************

Copyright (c) 1996, 2015, Oracle and/or its affiliates. All Rights Reserved.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file include/trx0rseg.h
Rollback segment

Created 3/26/1996 Heikki Tuuri
*******************************************************/

#ifndef trx0rseg_h
#define trx0rseg_h

#include "univ.i"
#include "trx0types.h"
#include "trx0sys.h"
#include "fut0lst.h"
#include <vector>

/** Gets a rollback segment header.
@param[in]	space		space where placed
@param[in]	page_no		page number of the header
@param[in]	page_size	page size
@param[in,out]	mtr		mini-transaction
@return rollback segment header, page x-latched */
UNIV_INLINE
trx_rsegf_t*
trx_rsegf_get(
	ulint			space,
	ulint			page_no,
	const page_size_t&	page_size,
	mtr_t*			mtr);

/** Gets a newly created rollback segment header.
@param[in]	space		space where placed
@param[in]	page_no		page number of the header
@param[in]	page_size	page size
@param[in,out]	mtr		mini-transaction
@return rollback segment header, page x-latched */
UNIV_INLINE
trx_rsegf_t*
trx_rsegf_get_new(
	ulint			space,
	ulint			page_no,
	const page_size_t&	page_size,
	mtr_t*			mtr);

/***************************************************************//**
Gets the file page number of the nth undo log slot.
@return page number of the undo log segment */
UNIV_INLINE
ulint
trx_rsegf_get_nth_undo(
/*===================*/
	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
	ulint		n,	/*!< in: index of slot */
	mtr_t*		mtr);	/*!< in: mtr */
/***************************************************************//**
Sets the file page number of the nth undo log slot. */
UNIV_INLINE
void
trx_rsegf_set_nth_undo(
/*===================*/
	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
	ulint		n,	/*!< in: index of slot */
	ulint		page_no,/*!< in: page number of the undo log segment */
	mtr_t*		mtr);	/*!< in: mtr */
/****************************************************************//**
Looks for a free slot for an undo log segment.
@return slot index or ULINT_UNDEFINED if not found */
UNIV_INLINE
ulint
trx_rsegf_undo_find_free(
/*=====================*/
	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
	mtr_t*		mtr);	/*!< in: mtr */
/******************************************************************//**
Looks for a rollback segment, based on the rollback segment id.
@return rollback segment */
UNIV_INLINE
trx_rseg_t*
trx_rseg_get_on_id(
/*===============*/
	ulint	id,		/*!< in: rollback segment id */
	bool	is_redo_rseg);	/*!< in: true if redo rseg else false. */

/** Creates a rollback segment header.
This function is called only when a new rollback segment is created in
the database.
@param[in]	space		space id
@param[in]	page_size	page size
@param[in]	max_size	max size in pages
@param[in]	rseg_slot_no	rseg id == slot number in trx sys
@param[in,out]	mtr		mini-transaction
@return page number of the created segment, FIL_NULL if fail */
ulint
trx_rseg_header_create(
	ulint			space,
	const page_size_t&	page_size,
	ulint			max_size,
	ulint			rseg_slot_no,
	mtr_t*			mtr);

/*********************************************************************//**
Creates the memory copies for rollback segments and initializes the
rseg array in trx_sys at a database startup. */
void
trx_rseg_array_init(
/*================*/
	purge_pq_t*	purge_queue);	/*!< in: rseg queue */

/***************************************************************************
Free's an instance of the rollback segment in memory. */
void
trx_rseg_mem_free(
/*==============*/
	trx_rseg_t*	rseg,		/*!< in, own: instance to free */
	trx_rseg_t**	rseg_array);	/*!< out: add rseg reference to this
					central array. */
/*********************************************************************
Creates a rollback segment. */
trx_rseg_t*
trx_rseg_create(
/*============*/
	ulint	space_id,	/*!< in: id of UNDO tablespace */
	ulint   nth_free_slot);	/*!< in: allocate nth free slot.
				0 means next free slots. */

/********************************************************************
Get the number of unique rollback tablespaces in use except space id 0.
The last space id will be the sentinel value ULINT_UNDEFINED. The array
will be sorted on space id. Note: space_ids should have have space for
TRX_SYS_N_RSEGS + 1 elements.
@return number of unique rollback tablespaces in use. */
ulint
trx_rseg_get_n_undo_tablespaces(
/*============================*/
	ulint*		space_ids);	/*!< out: array of space ids of
					UNDO tablespaces */
/* Number of undo log slots in a rollback segment file copy */
#define TRX_RSEG_N_SLOTS	(UNIV_PAGE_SIZE / 16)

/* Maximum number of transactions supported by a single rollback segment */
#define TRX_RSEG_MAX_N_TRXS	(TRX_RSEG_N_SLOTS / 2)

/** The rollback segment memory object */
struct trx_rseg_t {
	/*--------------------------------------------------------*/
	/** rollback segment id == the index of its slot in the trx
	system file copy */
	ulint				id;

	/** mutex protecting the fields in this struct except id,space,page_no
	which are constant */
	RsegMutex			mutex;

	/** space where the rollback segment header is placed */
	ulint				space;

	/** page number of the rollback segment header */
	ulint				page_no;

	/** page size of the relevant tablespace */
	page_size_t			page_size;

	/** maximum allowed size in pages */
	ulint				max_size;

	/** current size in pages */
	ulint				curr_size;

	/*--------------------------------------------------------*/
	/* Fields for update undo logs */
	/** List of update undo logs */
	UT_LIST_BASE_NODE_T(trx_undo_t)	update_undo_list;

	/** List of update undo log segments cached for fast reuse */
	UT_LIST_BASE_NODE_T(trx_undo_t)	update_undo_cached;

	/*--------------------------------------------------------*/
	/* Fields for insert undo logs */
	/** List of insert undo logs */
	UT_LIST_BASE_NODE_T(trx_undo_t) insert_undo_list;

	/** List of insert undo log segments cached for fast reuse */
	UT_LIST_BASE_NODE_T(trx_undo_t) insert_undo_cached;

	/*--------------------------------------------------------*/

	/** Page number of the last not yet purged log header in the history
	list; FIL_NULL if all list purged */
	ulint				last_page_no;

	/** Byte offset of the last not yet purged log header */
	ulint				last_offset;

	/** Transaction number of the last not yet purged log */
	trx_id_t			last_trx_no;

	/** TRUE if the last not yet purged log needs purging */
	ibool				last_del_marks;

	/** Reference counter to track rseg allocated transactions. */
	ulint				trx_ref_count;

	/** If true, then skip allocating this rseg as it reside in
	UNDO-tablespace marked for truncate. */
	bool				skip_allocation;
};

/* Undo log segment slot in a rollback segment header */
/*-------------------------------------------------------------*/
#define	TRX_RSEG_SLOT_PAGE_NO	0	/* Page number of the header page of
					an undo log segment */
/*-------------------------------------------------------------*/
/* Slot size */
#define TRX_RSEG_SLOT_SIZE	4

/* The offset of the rollback segment header on its page */
#define	TRX_RSEG		FSEG_PAGE_DATA

/* Transaction rollback segment header */
/*-------------------------------------------------------------*/
#define	TRX_RSEG_MAX_SIZE	0	/* Maximum allowed size for rollback
					segment in pages */
#define	TRX_RSEG_HISTORY_SIZE	4	/* Number of file pages occupied
					by the logs in the history list */
#define	TRX_RSEG_HISTORY	8	/* The update undo logs for committed
					transactions */
#define	TRX_RSEG_FSEG_HEADER	(8 + FLST_BASE_NODE_SIZE)
					/* Header for the file segment where
					this page is placed */
#define TRX_RSEG_UNDO_SLOTS	(8 + FLST_BASE_NODE_SIZE + FSEG_HEADER_SIZE)
					/* Undo log segment slots */
/*-------------------------------------------------------------*/

#ifndef UNIV_NONINL
#include "trx0rseg.ic"
#endif

#endif
