~drizzle-trunk/drizzle/development

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

Copyright (c) 1995, 2009, Innobase Oy. 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 as published by the Free Software

Foundation; version 2 of the License.

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 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., 59 Temple

Place, Suite 330, Boston, MA 02111-1307 USA

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

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

Mini-transaction buffer

Created 11/26/1995 Heikki Tuuri

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

#include "mtr0mtr.h"

#ifdef UNIV_NONINL

#include "mtr0mtr.ic"

#endif

#include "buf0buf.h"

#include "page0types.h"

#include "mtr0log.h"

#include "log0log.h"

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

Releases the item in the slot given. */

UNIV_INLINE

void

mtr_memo_slot_release(

/*==================*/

	mtr_t*			mtr,	/* in: mtr */

	mtr_memo_slot_t*	slot)	/* in: memo slot */

{

	void*	object;

	ulint	type;

	ut_ad(mtr && slot);

	object = slot->object;

	type = slot->type;

	if (UNIV_LIKELY(object != NULL)) {

		if (type <= MTR_MEMO_BUF_FIX) {

			buf_page_release((buf_block_t*)object, type, mtr);

		} else if (type == MTR_MEMO_S_LOCK) {

			rw_lock_s_unlock((rw_lock_t*)object);

#ifdef UNIV_DEBUG

		} else if (type != MTR_MEMO_X_LOCK) {

			ut_ad(type == MTR_MEMO_MODIFY);

			ut_ad(mtr_memo_contains(mtr, object,

						MTR_MEMO_PAGE_X_FIX));

#endif /* UNIV_DEBUG */

		} else {

			rw_lock_x_unlock((rw_lock_t*)object);

		}

	}

	slot->object = NULL;

}

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

Releases the mlocks and other objects stored in an mtr memo. They are released

in the order opposite to which they were pushed to the memo. NOTE! It is

essential that the x-rw-lock on a modified buffer page is not released before

buf_page_note_modification is called for that page! Otherwise, some thread

might race to modify it, and the flush list sort order on lsn would be

destroyed. */

UNIV_INLINE

void

mtr_memo_pop_all(

/*=============*/

	mtr_t*	mtr)	/* in: mtr */

{

	mtr_memo_slot_t* slot;

	dyn_array_t*	memo;

	ulint		offset;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	ut_ad(mtr->state == MTR_COMMITTING); /* Currently only used in

					     commit */

	memo = &(mtr->memo);

	offset = dyn_array_get_data_size(memo);

	while (offset > 0) {

		offset -= sizeof(mtr_memo_slot_t);

		slot = dyn_array_get_element(memo, offset);

		mtr_memo_slot_release(mtr, slot);

	}

}

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

Writes the contents of a mini-transaction log, if any, to the database log. */

static

void

mtr_log_reserve_and_write(

/*======================*/

	mtr_t*	mtr)	/* in: mtr */

{

	dyn_array_t*	mlog;

	dyn_block_t*	block;

	ulint		data_size;

	ibool		success;

	byte*		first_data;

	ut_ad(mtr);

	mlog = &(mtr->log);

	first_data = dyn_block_get_data(mlog);

	if (mtr->n_log_recs > 1) {

		mlog_catenate_ulint(mtr, MLOG_MULTI_REC_END, MLOG_1BYTE);

	} else {

		*first_data = (byte)((ulint)*first_data

				     | MLOG_SINGLE_REC_FLAG);

	}

	if (mlog->heap == NULL) {

		mtr->end_lsn = log_reserve_and_write_fast(

			first_data, dyn_block_get_used(mlog),

			&(mtr->start_lsn), &success);

		if (success) {

			return;

		}

	}

	data_size = dyn_array_get_data_size(mlog);

	/* Open the database log for log_write_low */

	mtr->start_lsn = log_reserve_and_open(data_size);

	if (mtr->log_mode == MTR_LOG_ALL) {

		block = mlog;

		while (block != NULL) {

			log_write_low(dyn_block_get_data(block),

				      dyn_block_get_used(block));

			block = dyn_array_get_next_block(mlog, block);

		}

	} else {

		ut_ad(mtr->log_mode == MTR_LOG_NONE);

		/* Do nothing */

	}

	mtr->end_lsn = log_close();

}

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

Commits a mini-transaction. */

UNIV_INTERN

void

mtr_commit(

/*=======*/

	mtr_t*	mtr)	/* in: mini-transaction */

{

	ibool		write_log;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	ut_ad(mtr->state == MTR_ACTIVE);

	ut_d(mtr->state = MTR_COMMITTING);

	write_log = mtr->modifications && mtr->n_log_recs;

	if (write_log) {

		mtr_log_reserve_and_write(mtr);

	}

	/* We first update the modification info to buffer pages, and only

	after that release the log mutex: this guarantees that when the log

	mutex is free, all buffer pages contain an up-to-date info of their

	modifications. This fact is used in making a checkpoint when we look

	at the oldest modification of any page in the buffer pool. It is also

	required when we insert modified buffer pages in to the flush list

	which must be sorted on oldest_modification. */

	mtr_memo_pop_all(mtr);

	if (write_log) {

		log_release();

	}

	ut_d(mtr->state = MTR_COMMITTED);

	dyn_array_free(&(mtr->memo));

	dyn_array_free(&(mtr->log));

}

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

Releases the latches stored in an mtr memo down to a savepoint.

NOTE! The mtr must not have made changes to buffer pages after the

savepoint, as these can be handled only by mtr_commit. */

UNIV_INTERN

void

mtr_rollback_to_savepoint(

/*======================*/

	mtr_t*	mtr,		/* in: mtr */

	ulint	savepoint)	/* in: savepoint */

{

	mtr_memo_slot_t* slot;

	dyn_array_t*	memo;

	ulint		offset;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	ut_ad(mtr->state == MTR_ACTIVE);

	memo = &(mtr->memo);

	offset = dyn_array_get_data_size(memo);

	ut_ad(offset >= savepoint);

	while (offset > savepoint) {

		offset -= sizeof(mtr_memo_slot_t);

		slot = dyn_array_get_element(memo, offset);

		ut_ad(slot->type != MTR_MEMO_MODIFY);

		mtr_memo_slot_release(mtr, slot);

	}

}

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

Releases an object in the memo stack. */

UNIV_INTERN

void

mtr_memo_release(

/*=============*/

	mtr_t*	mtr,	/* in: mtr */

	void*	object,	/* in: object */

	ulint	type)	/* in: object type: MTR_MEMO_S_LOCK, ... */

{

	mtr_memo_slot_t* slot;

	dyn_array_t*	memo;

	ulint		offset;

	ut_ad(mtr);

	ut_ad(mtr->magic_n == MTR_MAGIC_N);

	ut_ad(mtr->state == MTR_ACTIVE);

	memo = &(mtr->memo);

	offset = dyn_array_get_data_size(memo);

	while (offset > 0) {

		offset -= sizeof(mtr_memo_slot_t);

		slot = dyn_array_get_element(memo, offset);

		if ((object == slot->object) && (type == slot->type)) {

			mtr_memo_slot_release(mtr, slot);

			break;

		}

	}

}

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

Reads 1 - 4 bytes from a file page buffered in the buffer pool. */

UNIV_INTERN

ulint

mtr_read_ulint(

/*===========*/

				/* out: value read */

	const byte*	ptr,	/* in: pointer from where to read */

	ulint		type,	/* in: MLOG_1BYTE, MLOG_2BYTES, MLOG_4BYTES */

	mtr_t*		mtr __attribute__((unused)))

				/* in: mini-transaction handle */

{

	ut_ad(mtr->state == MTR_ACTIVE);

	ut_ad(mtr_memo_contains_page(mtr, ptr, MTR_MEMO_PAGE_S_FIX)

	      || mtr_memo_contains_page(mtr, ptr, MTR_MEMO_PAGE_X_FIX));

	if (type == MLOG_1BYTE) {

		return(mach_read_from_1(ptr));

	} else if (type == MLOG_2BYTES) {

		return(mach_read_from_2(ptr));

	} else {

		ut_ad(type == MLOG_4BYTES);

		return(mach_read_from_4(ptr));

	}

}

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

Reads 8 bytes from a file page buffered in the buffer pool. */

UNIV_INTERN

dulint

mtr_read_dulint(

/*============*/

				/* out: value read */

	const byte*	ptr,	/* in: pointer from where to read */

	mtr_t*		mtr __attribute__((unused)))

				/* in: mini-transaction handle */

{

	ut_ad(mtr->state == MTR_ACTIVE);

	ut_ad(mtr_memo_contains_page(mtr, ptr, MTR_MEMO_PAGE_S_FIX)

	      || mtr_memo_contains_page(mtr, ptr, MTR_MEMO_PAGE_X_FIX));

	return(mach_read_from_8(ptr));

}

#ifdef UNIV_DEBUG

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

Checks if memo contains the given page. */

UNIV_INTERN

ibool

mtr_memo_contains_page(

/*===================*/

				/* out: TRUE if contains */

	mtr_t*		mtr,	/* in: mtr */

	const byte*	ptr,	/* in: pointer to buffer frame */

	ulint		type)	/* in: type of object */

{

	return(mtr_memo_contains(mtr, buf_block_align(ptr), type));

}

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

Prints info of an mtr handle. */

UNIV_INTERN

void

mtr_print(

/*======*/

	mtr_t*	mtr)	/* in: mtr */

{

	fprintf(stderr,

		"Mini-transaction handle: memo size %lu bytes"

		" log size %lu bytes\n",

		(ulong) dyn_array_get_data_size(&(mtr->memo)),

		(ulong) dyn_array_get_data_size(&(mtr->log)));

}

#endif /* UNIV_DEBUG */