rem0types.h

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/** @file include/rem0types.h
 Record manager global types
 
 Created 5/30/1994 Heikki Tuuri
 *************************************************************************/
 
#ifndef rem0types_h
#define rem0types_h
 
#include "data0type.h"
#include "univ.i"
 
/* We define the physical record simply as an array of bytes */
typedef byte rec_t;
 
/* Maximum number of rows version allowed when columns are added/dropped
INSTANTly. After this limit is reached, any attempt to do ADD/DROP INSTANT
column will result in error. */
const uint8_t MAX_ROW_VERSION = 255;
 
/* Type of Row version which is stamped on rows inserted/updated after an
INSTANT ADD/DROP column is done. Maximum allowed row version is MAX_ROW_VERSION
which is 255. This is stamped on rows header on disk in 1 byte. But in-memory,
we use uint16_t to represent a row version to accommodate invalid row versions
which is defined as INVALID_ROW_VERSION. */
using row_version_t = uint16_t;
 
/* Invalid row version */
const row_version_t INVALID_ROW_VERSION = UINT16_UNDEFINED;
 
/* Maximum values for various fields (for non-blob tuples) */
constexpr uint32_t REC_MAX_N_FIELDS = 1024 - 1;
constexpr uint32_t REC_MAX_HEAP_NO = 2 * 8192 - 1;
constexpr uint32_t REC_MAX_N_OWNED = 16 - 1;
 
/* Maximum number of user defined fields/columns. The reserved columns
are the ones InnoDB adds internally: DB_ROW_ID, DB_TRX_ID, DB_ROLL_PTR.
We need "* 2" because mlog_parse_index() creates a dummy table object
possibly, with some of the system columns in it, and then adds the 3
system columns (again) using dict_table_add_system_columns(). The problem
is that mlog_parse_index() cannot recognize the system columns by
just having n_fields, n_uniq and the lengths of the columns. */
constexpr uint32_t REC_MAX_N_USER_FIELDS =
    REC_MAX_N_FIELDS - DATA_N_SYS_COLS * 2;
 
/* REC_ANTELOPE_MAX_INDEX_COL_LEN is measured in bytes and is the maximum
indexed field length (or indexed prefix length) for indexes on tables of
ROW_FORMAT=REDUNDANT and ROW_FORMAT=COMPACT format.
Before we support UTF-8 encodings with mbmaxlen = 4, a UTF-8 character
may take at most 3 bytes.  So the limit was set to 3*256, so that one
can create a column prefix index on 256 characters of a TEXT or VARCHAR
column also in the UTF-8 charset.
This constant MUST NOT BE CHANGED, or the compatibility of InnoDB data
files would be at risk! */
constexpr uint32_t REC_ANTELOPE_MAX_INDEX_COL_LEN = 768;
 
/** Maximum indexed field length for tables that have atomic BLOBs.
This (3072) is the maximum index row length allowed, so we cannot create index
prefix column longer than that. */
constexpr uint32_t REC_VERSION_56_MAX_INDEX_COL_LEN = 3072;
 
/** Innodb row types are a subset of the MySQL global enum row_type.
They are made into their own enum so that switch statements can account
for each of them. */
enum rec_format_enum {
  REC_FORMAT_REDUNDANT = 0,  /*!< REDUNDANT row format */
  REC_FORMAT_COMPACT = 1,    /*!< COMPACT row format */
  REC_FORMAT_COMPRESSED = 2, /*!< COMPRESSED row format */
  REC_FORMAT_DYNAMIC = 3     /*!< DYNAMIC row format */
};
typedef enum rec_format_enum rec_format_t;
 
#endif