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mariadb/sql/unireg.h
Sachin Setiya 84726906c9 MDEV-10177 Invisible Columns and Invisible Index 
Feature Definition:-

This feature adds invisible column functionality to server.
There is 4 level of "invisibility":

1. Not invisible (NOT_INVISIBLE) — Normal columns created by the user

2. A little bit invisible (USER_DEFINED_INVISIBLE) — columns that the
    user has marked invisible. They aren't shown in SELECT * and they
    don't require values in INSERT table VALUE (...). Otherwise
    they behave as normal columns.

3. More invisible (SYSTEM_INVISIBLE) — Can be queried explicitly,
    otherwise invisible from everything. Think ROWID sytem column.
    Because they're invisible from ALTER TABLE and from CREATE TABLE
    they cannot be created or dropped, they're created by the system.
    User cant not create a column name which is same as of
    SYSTEM_INVISIBLE.

4. Very invisible (COMPLETELY_INVISIBLE) — as above, but cannot be
    queried either. They can only show up in EXPLAIN EXTENDED (might
    be possible for a very invisible indexed virtual column) but
    otherwise they don't exist for the user.If user creates a columns
    which has same name as of COMPLETELY_INVISIBLE then
    COMPLETELY_INVISIBLE column is renamed again. So it is completely
    invisible from user.

Invisible Index(HA_INVISIBLE_KEY):-
   Creation of invisible columns require a new type of index which
   will be only visible to system. User cant see/alter/create/delete
   this index. If user creates a index which is same name as of
   invisible index then it will be renamed.

Syntax Details:-

  Only USER_DEFINED_INVISIBLE column can be created by user. This
  can be created by adding INVISIBLE suffix after column definition.

  Create table t1( a int invisible, b int);

Rules:-
  There are some rules/restrictions related to use of invisible columns
  1. All the columns in table cant be invisible.
     Create table t1(a int invisible); \\error
     Create table t1(a int invisible, b int invisble); \\error
  2. If you want invisible column to be NOT NULL then you have to supply
     Default value for the column.
     Create table t1(a int, b int not null); \\error
  3. If you create a view/create table with select * then this wont copy
     invisible fields. So newly created view/table wont have any invisible
     columns.
     Create table t2 as select * from t1;//t2 wont have t1 invisible column
     Create view v1 as select * from t1;//v1 wont have t1 invisible column
  4. Invisibility wont be forwarded to next table in any case of create
     table/view as select */(a,b,c) from table.
     Create table t2 as select a,b,c from t1; // t2 will have t1 invisible
                           // column(b), but this wont be invisible in t2
     Create view v1 as select a,b,c from t1; // v1 will have t1 invisible
                           // column(b), but this wont be invisible in v1

Implementation Details:-
  Parsing:- INVISIBLE_SYM is added into vcol_attribute(so its like unique
      suffix), It is also added into keyword_sp_not_data_type so that table
      can have column with name invisible.
  Implementation detail is given by each modified function/created function.
   (Some function are left as they were self explanatory)
   (m= Modified, n= Newly Created)

  mysql_prepare_create_table(m):- Extra checks for invisible columns are
  added. Also some DEBUG_EXECUTE_IF are also added for test cases.

  mysql_prepare_alter_table(m):- Now this will drop all the
  COMPLETELY_INVISIBLE column and HA_INVISIBLE_KEY index. Further
  Modifications are made to stop drop/change/delete of SYSTEM_INVISIBLE
  column.

  build_frm_image(m):- Now this allows incorporating field_visibility
  status into frm image. To remain compatible with old frms
  field_visibility info will be only written when any of the field is
  not NOT_INVISIBLE.

  extra2_write_additional_field_properties(n):- This will write field
  visibility info into buffer. We first write EXTRA2_FIELD_FLAGS into
  buffer/frm , then each next char will have field_visibility for each
  field.

  init_from_binary_frm_image(m):- Now if we get EXTRA2_FIELD_FLAGS,
  then we will read the next n(n= number of fields) chars and set the
  field_visibility. We also increment
  thd->status_var.feature_invisible_columns. One important thing to
  note if we find out that key contains a field whose visibility is
  > USER_DEFINED_INVISIBLE then , we declare this key as invisible
  key.

  sql_show.cc is changed accordingly to make show table, show keys
  correct.

  mysql_insert(m):- If we get to know that we are doing insert in
  this way insert into t1 values(1,1); without explicitly specifying
  columns, then we check for if we have invisible fields if yes then
  we reset the whole record, Why ? Because first we want hidden columns
  to get default/null value. Second thing auto_increment has property
  no default and no null which voilates invisible key rule 2, And
  because of this it was giving error. Reseting table->record[0]
  eliminates this issue. More info put breakpoint on handler::write_row
  and see auto_increment value.

  fill_record(m):- we continue loop if we find invisible column because
  this is already reseted/will get its value if it is default.

Test cases:- Since we can not directly add > USER_DEFINED_INVISIBLE
  column then I have debug_dbug to create it in mysql_prepare_create_table.

  Patch Credit:- Serg Golubchik
2017-12-15 02:41:52 +05:30

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#ifndef UNIREG_INCLUDED
#define UNIREG_INCLUDED
/*
Copyright (c) 2000, 2011, Oracle and/or its affiliates.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */
#include <mysql_version.h> /* FRM_VER */
/* Extra functions used by unireg library */
#ifndef NO_ALARM_LOOP
#define NO_ALARM_LOOP /* lib5 and popen can't use alarm */
#endif
/* These paths are converted to other systems (WIN95) before use */
#define LANGUAGE "english/"
#define ERRMSG_FILE "errmsg.sys"
#define TEMP_PREFIX "MY"
#define LOG_PREFIX "ML"
#define PROGDIR "bin/"
#ifndef MYSQL_DATADIR
#define MYSQL_DATADIR "data/"
#endif
#ifndef SHAREDIR
#define SHAREDIR "share/"
#endif
#ifndef PLUGINDIR
#define PLUGINDIR "lib/plugin"
#endif
#define MAX_ERROR_RANGES 4 /* 1000-2000, 2000-3000, 3000-4000, 4000-5000 */
#define ERRORS_PER_RANGE 1000
#define DEFAULT_ERRMSGS my_default_lc_messages->errmsgs->errmsgs
#define CURRENT_THD_ERRMSGS (current_thd)->variables.errmsgs
#define ER_DEFAULT(X) DEFAULT_ERRMSGS[((X)-ER_ERROR_FIRST) / ERRORS_PER_RANGE][(X)% ERRORS_PER_RANGE]
#define ER_THD(thd,X) ((thd)->variables.errmsgs[((X)-ER_ERROR_FIRST) / ERRORS_PER_RANGE][(X) % ERRORS_PER_RANGE])
#define ER(X) ER_THD(current_thd, (X))
#define ER_THD_OR_DEFAULT(thd,X) ((thd) ? ER_THD(thd, (X)) : ER_DEFAULT(X))
#define ME_INFO (ME_HOLDTANG | ME_NOREFRESH)
#define ME_ERROR (ME_BELL | ME_NOREFRESH)
#define MYF_RW MYF(MY_WME+MY_NABP) /* Vid my_read & my_write */
#define SPECIAL_USE_LOCKS 1 /* Lock used databases */
#define SPECIAL_NO_NEW_FUNC 2 /* Skip new functions */
#define SPECIAL_SKIP_SHOW_DB 4 /* Don't allow 'show db' */
#define SPECIAL_WAIT_IF_LOCKED 8 /* Wait if locked database */
#define SPECIAL_SAME_DB_NAME 16 /* form name = file name */
#define SPECIAL_ENGLISH 32 /* English error messages */
#define SPECIAL_NO_RESOLVE 64 /* Don't use gethostname */
#define SPECIAL_NO_PRIOR 128 /* Obsolete */
#define SPECIAL_BIG_SELECTS 256 /* Don't use heap tables */
#define SPECIAL_NO_HOST_CACHE 512 /* Don't cache hosts */
#define SPECIAL_SHORT_LOG_FORMAT 1024
#define SPECIAL_SAFE_MODE 2048
#define SPECIAL_LOG_QUERIES_NOT_USING_INDEXES 4096 /* Obsolete */
/* Extern defines */
#define store_record(A,B) memcpy((A)->B,(A)->record[0],(size_t) (A)->s->reclength)
#define restore_record(A,B) memcpy((A)->record[0],(A)->B,(size_t) (A)->s->reclength)
#define cmp_record(A,B) memcmp((A)->record[0],(A)->B,(size_t) (A)->s->reclength)
#define empty_record(A) { \
restore_record((A),s->default_values); \
bfill((A)->null_flags,(A)->s->null_bytes,255);\
}
/* Defines for use with openfrm, openprt and openfrd */
#define READ_ALL (1 << 0) /* openfrm: Read all parameters */
#define EXTRA_RECORD (1 << 3) /* Reserve space for an extra record */
#define DELAYED_OPEN (1 << 12) /* Open table later */
#define OPEN_VIEW_NO_PARSE (1 << 14) /* Open frm only if it's a view,
but do not parse view itself */
/**
This flag is used in function get_all_tables() which fills
I_S tables with data which are retrieved from frm files and storage engine
The flag means that we need to open FRM file only to get necessary data.
*/
#define OPEN_FRM_FILE_ONLY (1 << 15)
/**
This flag is used in function get_all_tables() which fills
I_S tables with data which are retrieved from frm files and storage engine
The flag means that we need to process tables only to get necessary data.
Views are not processed.
*/
#define OPEN_TABLE_ONLY (1 << 16)
/**
This flag is used in function get_all_tables() which fills
I_S tables with data which are retrieved from frm files and storage engine
The flag means that we need to process views only to get necessary data.
Tables are not processed.
*/
#define OPEN_VIEW_ONLY (1 << 17)
/**
This flag is used in function get_all_tables() which fills
I_S tables with data which are retrieved from frm files and storage engine.
The flag means that we need to open a view using
open_normal_and_derived_tables() function.
*/
#define OPEN_VIEW_FULL (1 << 18)
/**
This flag is used in function get_all_tables() which fills
I_S tables with data which are retrieved from frm files and storage engine.
The flag means that I_S table uses optimization algorithm.
*/
#define OPTIMIZE_I_S_TABLE (1 << 19)
/**
This flag is used to instruct tdc_open_view() to check metadata version.
*/
#define CHECK_METADATA_VERSION (1 << 20)
/*
The flag means that we need to process trigger files only.
*/
#define OPEN_TRIGGER_ONLY (1 << 21)
/*
Minimum length pattern before Turbo Boyer-Moore is used
for SELECT "text" LIKE "%pattern%", excluding the two
wildcards in class Item_func_like.
*/
#define MIN_TURBOBM_PATTERN_LEN 3
/*
Defines for binary logging.
Do not decrease the value of BIN_LOG_HEADER_SIZE.
Do not even increase it before checking code.
*/
#define BIN_LOG_HEADER_SIZE 4
#define DEFAULT_KEY_CACHE_NAME "default"
/* Include prototypes for unireg */
#include "mysqld_error.h"
#include "structs.h" /* All structs we need */
#include "sql_list.h" /* List<> */
#include "field.h" /* Create_field */
/*
Types of values in the MariaDB extra2 frm segment.
Each value is written as
type: 1 byte
length: 1 byte (1..255) or \0 and 2 bytes.
binary value of the 'length' bytes.
Older MariaDB servers can ignore values of unknown types if
the type code is less than 128 (EXTRA2_ENGINE_IMPORTANT).
Otherwise older (but newer than 10.0.1) servers are required
to report an error.
*/
enum extra2_frm_value_type {
EXTRA2_TABLEDEF_VERSION=0,
EXTRA2_DEFAULT_PART_ENGINE=1,
EXTRA2_GIS=2,
#define EXTRA2_ENGINE_IMPORTANT 128
EXTRA2_ENGINE_TABLEOPTS=128,
EXTRA2_FIELD_FLAGS=129
};
int rea_create_table(THD *thd, LEX_CUSTRING *frm,
const char *path, const char *db, const char *table_name,
HA_CREATE_INFO *create_info, handler *file,
bool no_ha_create_table);
LEX_CUSTRING build_frm_image(THD *thd, const char *table,
HA_CREATE_INFO *create_info,
List<Create_field> &create_fields,
uint keys, KEY *key_info, handler *db_file);
#define FRM_HEADER_SIZE 64
#define FRM_FORMINFO_SIZE 288
#define FRM_MAX_SIZE (512*1024)
static inline bool is_binary_frm_header(uchar *head)
{
return head[0] == 254
&& head[1] == 1
&& head[2] >= FRM_VER
&& head[2] <= FRM_VER_CURRENT;
}
#endif
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