~drizzle-trunk/drizzle/development

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

Copyright (c) 2005, 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

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

/******************************************************
Compressed page interface

Created June 2005 by Marko Makela
*******************************************************/

#ifndef page0zip_h
#define page0zip_h

#ifdef UNIV_MATERIALIZE
# undef UNIV_INLINE
# define UNIV_INLINE
#endif

#include "mtr0types.h"
#include "page0types.h"
#include "buf0types.h"
#include "dict0types.h"
#include "mem0mem.h"

/**************************************************************************
Determine the size of a compressed page in bytes. */
UNIV_INLINE
ulint
page_zip_get_size(
/*==============*/
						/* out: size in bytes */
	const page_zip_des_t*	page_zip)	/* in: compressed page */
	__attribute__((nonnull, pure));
/**************************************************************************
Set the size of a compressed page in bytes. */
UNIV_INLINE
void
page_zip_set_size(
/*==============*/
	page_zip_des_t*	page_zip,	/* in/out: compressed page */
	ulint		size);		/* in: size in bytes */

/**************************************************************************
Determine if a record is so big that it needs to be stored externally. */
UNIV_INLINE
ibool
page_zip_rec_needs_ext(
/*===================*/
				/* out: FALSE if the entire record
				can be stored locally on the page */
	ulint	rec_size,	/* in: length of the record in bytes */
	ulint	comp,		/* in: nonzero=compact format */
	ulint	n_fields,	/* in: number of fields in the record;
				ignored if zip_size == 0 */
	ulint	zip_size)	/* in: compressed page size in bytes, or 0 */
	__attribute__((__const__));

/**************************************************************************
Determine the guaranteed free space on an empty page. */
UNIV_INTERN
ulint
page_zip_empty_size(
/*================*/
				/* out: minimum payload size on the page */
	ulint	n_fields,	/* in: number of columns in the index */
	ulint	zip_size)	/* in: compressed page size in bytes */
	__attribute__((const));

/**************************************************************************
Initialize a compressed page descriptor. */
UNIV_INLINE
void
page_zip_des_init(
/*==============*/
	page_zip_des_t*	page_zip);	/* in/out: compressed page
					descriptor */

/**************************************************************************
Configure the zlib allocator to use the given memory heap. */
UNIV_INTERN
void
page_zip_set_alloc(
/*===============*/
	void*		stream,		/* in/out: zlib stream */
	mem_heap_t*	heap);		/* in: memory heap to use */

/**************************************************************************
Compress a page. */
UNIV_INTERN
ibool
page_zip_compress(
/*==============*/
				/* out: TRUE on success, FALSE on failure;
				page_zip will be left intact on failure. */
	page_zip_des_t*	page_zip,/* in: size; out: data, n_blobs,
				m_start, m_end, m_nonempty */
	const page_t*	page,	/* in: uncompressed page */
	dict_index_t*	index,	/* in: index of the B-tree node */
	mtr_t*		mtr)	/* in: mini-transaction, or NULL */
	__attribute__((nonnull(1,2,3)));

/**************************************************************************
Decompress a page.  This function should tolerate errors on the compressed
page.  Instead of letting assertions fail, it will return FALSE if an
inconsistency is detected. */
UNIV_INTERN
ibool
page_zip_decompress(
/*================*/
				/* out: TRUE on success, FALSE on failure */
	page_zip_des_t*	page_zip,/* in: data, ssize;
				out: m_start, m_end, m_nonempty, n_blobs */
	page_t*		page)	/* out: uncompressed page, may be trashed */
	__attribute__((nonnull));

#ifdef UNIV_DEBUG
/**************************************************************************
Validate a compressed page descriptor. */
UNIV_INLINE
ibool
page_zip_simple_validate(
/*=====================*/
						/* out: TRUE if ok */
	const page_zip_des_t*	page_zip);	/* in: compressed page
						descriptor */
#endif /* UNIV_DEBUG */

#ifdef UNIV_ZIP_DEBUG
/**************************************************************************
Check that the compressed and decompressed pages match. */
UNIV_INTERN
ibool
page_zip_validate_low(
/*==================*/
					/* out: TRUE if valid, FALSE if not */
	const page_zip_des_t*	page_zip,/* in: compressed page */
	const page_t*		page,	/* in: uncompressed page */
	ibool			sloppy)	/* in: FALSE=strict,
					TRUE=ignore the MIN_REC_FLAG */
	__attribute__((nonnull));
/**************************************************************************
Check that the compressed and decompressed pages match. */
UNIV_INTERN
ibool
page_zip_validate(
/*==============*/
	const page_zip_des_t*	page_zip,/* in: compressed page */
	const page_t*		page)	/* in: uncompressed page */
	__attribute__((nonnull));
#endif /* UNIV_ZIP_DEBUG */

/**************************************************************************
Determine how big record can be inserted without recompressing the page. */
UNIV_INLINE
lint
page_zip_max_ins_size(
/*==================*/
					/* out: a positive number
					indicating the maximum size of
					a record whose insertion is
					guaranteed to succeed, or
					zero or negative */
	const page_zip_des_t*	page_zip,/* in: compressed page */
	ibool			is_clust)/* in: TRUE if clustered index */
	__attribute__((nonnull, pure));

/**************************************************************************
Determine if enough space is available in the modification log. */
UNIV_INLINE
ibool
page_zip_available(
/*===============*/
					/* out: TRUE if page_zip_write_rec()
					will succeed */
	const page_zip_des_t*	page_zip,/* in: compressed page */
	ibool			is_clust,/* in: TRUE if clustered index */
	ulint			length,	/* in: combined size of the record */
	ulint			create)	/* in: nonzero=add the record to
					the heap */
	__attribute__((nonnull, pure));

/**************************************************************************
Write an entire record on the compressed page.  The data must already
have been written to the uncompressed page. */
UNIV_INTERN
void
page_zip_write_rec(
/*===============*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	const byte*	rec,	/* in: record being written */
	dict_index_t*	index,	/* in: the index the record belongs to */
	const ulint*	offsets,/* in: rec_get_offsets(rec, index) */
	ulint		create)	/* in: nonzero=insert, zero=update */
	__attribute__((nonnull));

/***************************************************************
Parses a log record of writing a BLOB pointer of a record. */
UNIV_INTERN
byte*
page_zip_parse_write_blob_ptr(
/*==========================*/
				/* out: end of log record or NULL */
	byte*		ptr,	/* in: redo log buffer */
	byte*		end_ptr,/* in: redo log buffer end */
	page_t*		page,	/* in/out: uncompressed page */
	page_zip_des_t*	page_zip);/* in/out: compressed page */

/**************************************************************************
Write a BLOB pointer of a record on the leaf page of a clustered index.
The information must already have been updated on the uncompressed page. */
UNIV_INTERN
void
page_zip_write_blob_ptr(
/*====================*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	const byte*	rec,	/* in/out: record whose data is being
				written */
	dict_index_t*	index,	/* in: index of the page */
	const ulint*	offsets,/* in: rec_get_offsets(rec, index) */
	ulint		n,	/* in: column index */
	mtr_t*		mtr)	/* in: mini-transaction handle,
				or NULL if no logging is needed */
	__attribute__((nonnull(1,2,3,4)));

/***************************************************************
Parses a log record of writing the node pointer of a record. */
UNIV_INTERN
byte*
page_zip_parse_write_node_ptr(
/*==========================*/
				/* out: end of log record or NULL */
	byte*		ptr,	/* in: redo log buffer */
	byte*		end_ptr,/* in: redo log buffer end */
	page_t*		page,	/* in/out: uncompressed page */
	page_zip_des_t*	page_zip);/* in/out: compressed page */

/**************************************************************************
Write the node pointer of a record on a non-leaf compressed page. */
UNIV_INTERN
void
page_zip_write_node_ptr(
/*====================*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	byte*		rec,	/* in/out: record */
	ulint		size,	/* in: data size of rec */
	ulint		ptr,	/* in: node pointer */
	mtr_t*		mtr)	/* in: mini-transaction, or NULL */
	__attribute__((nonnull(1,2)));

/**************************************************************************
Write the trx_id and roll_ptr of a record on a B-tree leaf node page. */
UNIV_INTERN
void
page_zip_write_trx_id_and_roll_ptr(
/*===============================*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	byte*		rec,	/* in/out: record */
	const ulint*	offsets,/* in: rec_get_offsets(rec, index) */
	ulint		trx_id_col,/* in: column number of TRX_ID in rec */
	dulint		trx_id,	/* in: transaction identifier */
	dulint		roll_ptr)/* in: roll_ptr */
	__attribute__((nonnull));

/**************************************************************************
Insert a record to the dense page directory. */
UNIV_INTERN
void
page_zip_dir_insert(
/*================*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	const byte*	prev_rec,/* in: record after which to insert */
	const byte*	free_rec,/* in: record from which rec was
				allocated, or NULL */
	byte*		rec);	/* in: record to insert */

/***************************************************************
Parses a log record of writing to the header of a page. */
UNIV_INTERN
byte*
page_zip_parse_write_header(
/*========================*/
				/* out: end of log record or NULL */
	byte*		ptr,	/* in: redo log buffer */
	byte*		end_ptr,/* in: redo log buffer end */
	page_t*		page,	/* in/out: uncompressed page */
	page_zip_des_t*	page_zip);/* in/out: compressed page */

/**************************************************************************
Write data to the uncompressed header portion of a page.  The data must
already have been written to the uncompressed page.
However, the data portion of the uncompressed page may differ from
the compressed page when a record is being inserted in
page_cur_insert_rec_low(). */
UNIV_INLINE
void
page_zip_write_header(
/*==================*/
	page_zip_des_t*	page_zip,/* in/out: compressed page */
	const byte*	str,	/* in: address on the uncompressed page */
	ulint		length,	/* in: length of the data */
	mtr_t*		mtr)	/* in: mini-transaction, or NULL */
	__attribute__((nonnull(1,2)));

/**************************************************************************
Reorganize and compress a page.  This is a low-level operation for
compressed pages, to be used when page_zip_compress() fails.
On success, a redo log entry MLOG_ZIP_PAGE_COMPRESS will be written.
The function btr_page_reorganize() should be preferred whenever possible.
IMPORTANT: if page_zip_reorganize() is invoked on a leaf page of a
non-clustered index, the caller must update the insert buffer free
bits in the same mini-transaction in such a way that the modification
will be redo-logged. */
UNIV_INTERN
ibool
page_zip_reorganize(
/*================*/
				/* out: TRUE on success, FALSE on failure;
				page and page_zip will be left intact
				on failure. */
	buf_block_t*	block,	/* in/out: page with compressed page;
				on the compressed page, in: size;
				out: data, n_blobs,
				m_start, m_end, m_nonempty */
	dict_index_t*	index,	/* in: index of the B-tree node */
	mtr_t*		mtr)	/* in: mini-transaction */
	__attribute__((nonnull));
/**************************************************************************
Copy the records of a page byte for byte.  Do not copy the page header
or trailer, except those B-tree header fields that are directly
related to the storage of records.  Also copy PAGE_MAX_TRX_ID.
NOTE: The caller must update the lock table and the adaptive hash index. */
UNIV_INTERN
void
page_zip_copy_recs(
/*===============*/
	page_zip_des_t*		page_zip,	/* out: copy of src_zip
						(n_blobs, m_start, m_end,
						m_nonempty, data[0..size-1]) */
	page_t*			page,		/* out: copy of src */
	const page_zip_des_t*	src_zip,	/* in: compressed page */
	const page_t*		src,		/* in: page */
	dict_index_t*		index,		/* in: index of the B-tree */
	mtr_t*			mtr)		/* in: mini-transaction */
	__attribute__((nonnull(1,2,3,4)));

/**************************************************************************
Parses a log record of compressing an index page. */
UNIV_INTERN
byte*
page_zip_parse_compress(
/*====================*/
				/* out: end of log record or NULL */
	byte*		ptr,	/* in: buffer */
	byte*		end_ptr,/* in: buffer end */
	page_t*		page,	/* out: uncompressed page */
	page_zip_des_t*	page_zip)/* out: compressed page */
	__attribute__((nonnull(1,2)));

/**************************************************************************
Calculate the compressed page checksum. */
UNIV_INTERN
ulint
page_zip_calc_checksum(
/*===================*/
                                /* out: page checksum */
        const void*     data,   /* in: compressed page */
        ulint           size)   /* in: size of compressed page */
	__attribute__((nonnull));

#ifdef UNIV_MATERIALIZE
# undef UNIV_INLINE
# define UNIV_INLINE	UNIV_INLINE_ORIGINAL
#endif

#ifndef UNIV_NONINL
# include "page0zip.ic"
#endif

#endif /* page0zip_h */