MySQL 9.1.0
Source Code Documentation
fil0types.h
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27
28/** @file include/fil0types.h
29 The low-level file system page header & trailer offsets
30
31 Created 10/25/1995 Heikki Tuuri
32 *******************************************************/
33
34#ifndef fil0types_h
35#define fil0types_h
36
37#include "univ.i"
38
39/** The byte offsets on a file page for various variables. */
40
41/** MySQL-4.0.14 space id the page belongs to (== 0) but in later
42versions the 'new' checksum of the page */
43constexpr uint32_t FIL_PAGE_SPACE_OR_CHKSUM = 0;
44
45/** page offset inside space */
46constexpr uint32_t FIL_PAGE_OFFSET = 4;
47
48/** if there is a 'natural' predecessor of the page, its offset.
49Otherwise FIL_NULL. This field is not set on BLOB pages, which are stored as a
50singly-linked list. See also FIL_PAGE_NEXT. */
51constexpr uint32_t FIL_PAGE_PREV = 8;
52
53/** On page 0 of the tablespace, this is the server version ID */
54constexpr uint32_t FIL_PAGE_SRV_VERSION = 8;
55
56/** if there is a 'natural' successor of the page, its offset. Otherwise
57FIL_NULL. B-tree index pages(FIL_PAGE_TYPE contains FIL_PAGE_INDEX) on the
58same PAGE_LEVEL are maintained as a doubly linked list via FIL_PAGE_PREV and
59FIL_PAGE_NEXT in the collation order of the smallest user record on each
60page. */
61constexpr uint32_t FIL_PAGE_NEXT = 12;
62
63/** On page 0 of the tablespace, this is the server version ID */
64constexpr uint32_t FIL_PAGE_SPACE_VERSION = 12;
65
66/** lsn of the end of the newest modification log record to the page */
67constexpr uint32_t FIL_PAGE_LSN = 16;
68
69/** file page type: FIL_PAGE_INDEX,..., 2 bytes. The contents of this field
70can only be trusted in the following case: if the page is an uncompressed
71B-tree index page, then it is guaranteed that the value is FIL_PAGE_INDEX.
72The opposite does not hold.
73
74In tablespaces created by MySQL/InnoDB 5.1.7 or later, the contents of this
75field is valid for all uncompressed pages. */
76constexpr uint32_t FIL_PAGE_TYPE = 24;
77
78/** this is only defined for the first page of the system tablespace: the file
79has been flushed to disk at least up to this LSN. For FIL_PAGE_COMPRESSED
80pages, we store the compressed page control information in these 8 bytes. */
81constexpr uint32_t FIL_PAGE_FILE_FLUSH_LSN = 26;
82
83/** If page type is FIL_PAGE_COMPRESSED then the 8 bytes starting at
84FIL_PAGE_FILE_FLUSH_LSN are broken down as follows: */
85
86/** Control information version format (u8) */
88
89/** Compression algorithm (u8) */
90constexpr uint32_t FIL_PAGE_ALGORITHM_V1 = FIL_PAGE_VERSION + 1;
91
92/** Original page type (u16) */
94
95/** Original data size in bytes (u16)*/
97
98/** Size after compression (u16) */
100
101/** This overloads FIL_PAGE_FILE_FLUSH_LSN for RTREE Split Sequence Number */
103
104/** starting from 4.1.x this contains the space id of the page */
105constexpr uint32_t FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID = 34;
106
107/** alias for space id */
109
110/** start of the data on the page */
111constexpr uint32_t FIL_PAGE_DATA = 38;
112
113/** File page trailer */
114/** the low 4 bytes of this are used to store the page checksum, the
115last 4 bytes should be identical to the last 4 bytes of FIL_PAGE_LSN */
116constexpr uint32_t FIL_PAGE_END_LSN_OLD_CHKSUM = 8;
117
118/** size of the page trailer */
119constexpr uint32_t FIL_PAGE_DATA_END = 8;
120
121/** First in address is the page offset. */
122constexpr size_t FIL_ADDR_PAGE = 0;
123
124/** Then comes 2-byte byte offset within page.*/
125constexpr size_t FIL_ADDR_BYTE = 4;
126
127/** Address size is 6 bytes. */
128constexpr size_t FIL_ADDR_SIZE = 6;
129
130/** Path separator e.g., 'dir;...;dirN' */
131constexpr char FIL_PATH_SEPARATOR = ';';
132
133/** A wrapper class to help print and inspect the file page header. */
135 /** The constructor that takes a pointer to page header as argument.
136 @param[in] frame the pointer to the page header. */
137 explicit Fil_page_header(const byte *frame) : m_frame(frame) {}
138
139 /** Get the space id from the page header.
140 @return the space identifier. */
141 [[nodiscard]] space_id_t get_space_id() const noexcept;
142
143 /** Get the page number from the page header.
144 @return the page number. */
145 [[nodiscard]] page_no_t get_page_no() const noexcept;
146
147 /** Get the FIL_PAGE_PREV header value.
148 @return the previous page number. */
149 [[nodiscard]] page_no_t get_page_prev() const noexcept;
150
151 /** Get the FIL_PAGE_NEXT header value.
152 @return the next page number. */
153 [[nodiscard]] page_no_t get_page_next() const noexcept;
154
155 /** Get the page type from the page header.
156 @return the page type. */
157 [[nodiscard]] uint16_t get_page_type() const noexcept;
158
159 /** Print the page header to the given output stream.
160 @param[in] out the output stream.
161 @return the output stream. */
162 std::ostream &print(std::ostream &out) const noexcept;
163
164 private:
165 /** Pointer to the page header. */
166 const byte *m_frame{};
167};
168
169/** Overload the global output operator to handle an object of type
170Fil_page_header.
171@param[in] out the output stream.
172@param[in] header an object of type Fil_page_header.
173@return the output stream. */
174inline std::ostream &operator<<(std::ostream &out,
175 const Fil_page_header &header) noexcept {
176 return (header.print(out));
177}
178
179#endif /* fil0types_h */
uint32_t space_id_t
Tablespace identifier.
Definition: api0api.h:48
uint32_t page_no_t
Page number.
Definition: api0api.h:46
std::ostream & operator<<(std::ostream &out, const Fil_page_header &header) noexcept
Overload the global output operator to handle an object of type Fil_page_header.
Definition: fil0types.h:174
constexpr uint32_t FIL_PAGE_VERSION
If page type is FIL_PAGE_COMPRESSED then the 8 bytes starting at FIL_PAGE_FILE_FLUSH_LSN are broken d...
Definition: fil0types.h:87
constexpr uint32_t FIL_PAGE_COMPRESS_SIZE_V1
Size after compression (u16)
Definition: fil0types.h:99
constexpr uint32_t FIL_PAGE_TYPE
file page type: FIL_PAGE_INDEX,..., 2 bytes.
Definition: fil0types.h:76
constexpr size_t FIL_ADDR_PAGE
First in address is the page offset.
Definition: fil0types.h:122
constexpr uint32_t FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID
starting from 4.1.x this contains the space id of the page
Definition: fil0types.h:105
constexpr uint32_t FIL_PAGE_OFFSET
page offset inside space
Definition: fil0types.h:46
constexpr uint32_t FIL_PAGE_DATA
start of the data on the page
Definition: fil0types.h:111
constexpr size_t FIL_ADDR_SIZE
Address size is 6 bytes.
Definition: fil0types.h:128
constexpr uint32_t FIL_PAGE_FILE_FLUSH_LSN
this is only defined for the first page of the system tablespace: the file has been flushed to disk a...
Definition: fil0types.h:81
constexpr uint32_t FIL_PAGE_ORIGINAL_TYPE_V1
Original page type (u16)
Definition: fil0types.h:93
constexpr uint32_t FIL_PAGE_LSN
lsn of the end of the newest modification log record to the page
Definition: fil0types.h:67
constexpr uint32_t FIL_PAGE_SPACE_ID
alias for space id
Definition: fil0types.h:108
constexpr uint32_t FIL_PAGE_ALGORITHM_V1
Compression algorithm (u8)
Definition: fil0types.h:90
constexpr uint32_t FIL_PAGE_NEXT
if there is a 'natural' successor of the page, its offset.
Definition: fil0types.h:61
constexpr uint32_t FIL_PAGE_SPACE_OR_CHKSUM
The byte offsets on a file page for various variables.
Definition: fil0types.h:43
constexpr uint32_t FIL_PAGE_END_LSN_OLD_CHKSUM
File page trailer.
Definition: fil0types.h:116
constexpr uint32_t FIL_PAGE_PREV
if there is a 'natural' predecessor of the page, its offset.
Definition: fil0types.h:51
constexpr uint32_t FIL_PAGE_SPACE_VERSION
On page 0 of the tablespace, this is the server version ID.
Definition: fil0types.h:64
constexpr uint32_t FIL_PAGE_SRV_VERSION
On page 0 of the tablespace, this is the server version ID.
Definition: fil0types.h:54
constexpr uint32_t FIL_RTREE_SPLIT_SEQ_NUM
This overloads FIL_PAGE_FILE_FLUSH_LSN for RTREE Split Sequence Number.
Definition: fil0types.h:102
constexpr uint32_t FIL_PAGE_DATA_END
size of the page trailer
Definition: fil0types.h:119
constexpr char FIL_PATH_SEPARATOR
Path separator e.g., 'dir;...;dirN'.
Definition: fil0types.h:131
constexpr uint32_t FIL_PAGE_ORIGINAL_SIZE_V1
Original data size in bytes (u16)
Definition: fil0types.h:96
constexpr size_t FIL_ADDR_BYTE
Then comes 2-byte byte offset within page.
Definition: fil0types.h:125
Definition: gcs_xcom_synode.h:64
A wrapper class to help print and inspect the file page header.
Definition: fil0types.h:134
const byte * m_frame
Pointer to the page header.
Definition: fil0types.h:166
page_no_t get_page_prev() const noexcept
Get the FIL_PAGE_PREV header value.
Definition: fil0fil.cc:11665
Fil_page_header(const byte *frame)
The constructor that takes a pointer to page header as argument.
Definition: fil0types.h:137
page_no_t get_page_next() const noexcept
Get the FIL_PAGE_NEXT header value.
Definition: fil0fil.cc:11669
space_id_t get_space_id() const noexcept
Get the space id from the page header.
Definition: fil0fil.cc:11653
uint16_t get_page_type() const noexcept
Get the page type from the page header.
Definition: fil0fil.cc:11661
page_no_t get_page_no() const noexcept
Get the page number from the page header.
Definition: fil0fil.cc:11657
std::ostream & print(std::ostream &out) const noexcept
Print the page header to the given output stream.
Definition: fil0fil.cc:11643
Version control for database, common definitions, and include files.