← Back to team overview

maria-developers team mailing list archive

Re: MDEV-10142 - bb-10.2-compatibility

 

Hi Alexander,
I think something is wrong in Item_func_concat_operator_oracle, if the first argument is empty and the second argument is null ,then res is null and res->set_charset fail.
Example: select ''||null||'a'


for (i++ ; i < arg_count ; i++)
  {
    if (res->length() == 0)
    {
      // See comments in Item_func_concat::val_str()
-->>      if (!(res= arg_val_str(i, str, &is_const)))
        continue;
    }
    else
    {
      const String *res2;
      if (!(res2= args[i]->val_str(use_as_buff)))
        continue;
      if (!(res= append_value(res, is_const, str, &use_as_buff, res2)))
        goto null;
      is_const= 0;
    }
  }
-->>  res->set_charset(collation.collation);

Best regards,
Jérôme.


-----Message d'origine-----
De : Alexander Barkov [mailto:bar@xxxxxxxxxxx] 
Envoyé : lundi 23 janvier 2017 12:28
À : jerome brauge
Cc : MariaDB Developers; Sergei Golubchik
Objet : Re: MDEV-10142 - bb-10.2-compatibility

Hi Jerome,


On 01/19/2017 05:15 PM, jerome brauge wrote:
> Hello Alexander, Sergei,
> Concat function exists in Oracle, but it accepts only two operand. Due to this, it's not very useful and we don't use it. 

Thanks for clarification!

> Changing only operator || is fine for us.

I created an MDEV for this:
https://jira.mariadb.org/browse/MDEV-11880

and modified your patch to implement this approach.

To safe on performance slightly, I created two different classes for the MariaDB style concatenation and for Oracle style || concatenation.

Please find the new version attached. Do you think it's fine?


Note, before we can push it, we'd like to fix this problem first:

https://jira.mariadb.org/browse/MDEV-11848

Greetings.

> 
> Regards,
> Jérôme.
> 
> -----Message d'origine-----
> De : Alexander Barkov [mailto:bar@xxxxxxxxxxx] Envoyé : jeudi 19 
> janvier 2017 13:18 À : jerome brauge Cc : MariaDB Developers; Sergei 
> Golubchik Objet : Re: MDEV-10142 - bb-10.2-compatibility
> 
> Hello Jerome,
> 
> 
> On 01/16/2017 02:45 PM, jerome brauge wrote:
>> Hello Alexander,
>> According to your comments, this is the new version.
> 
> Thanks for addressing my suggestions.
> 
> We're discussing the change with our architect Sergei Golubchik.
> 
> Briefly, the idea is:
> 
> Perhaps we should not change the function CONCAT().
> This is a non-standard MySQL/MariaDB function, and it does not exist in Oracle. So probably it should stay sql_mode independent, while sql_mode should affect only the concatenation operator ||.
> 
> Would this solution work for you?
> 
> We're still discussing details. I'll get back to you soon.
> 
> Greetings.
> 
>>
>> Best regards,
>> Jérôme.
>>
>>
>> -----Message d'origine-----
>> De : Alexander Barkov [mailto:bar@xxxxxxxxxxx] Envoyé : vendredi 30 
>> décembre 2016 10:36 À : jerome brauge Cc : MariaDB Developers Objet :
>> Re: MDEV-10142 - bb-10.2-compatibility
>>
>>   Hello Jerome,
>>
>>
>> On 12/29/2016 08:15 PM, jerome brauge wrote:
>>> Hello Alexander,
>>> I built a patch for concat of strings and nulls when sql_mode=oracle.
>>> Can you review it ?
>>
>> Thank you very much for your patch.
>> It generally looks fine.
>> I suggest only small changes.
>>
>> Please see inline.
>>
>>>
>>> Best regards,
>>> Jérôme.
>>>
>>>
>>
>>
>>> From 6250ce0bcfe563491b25d2e1b4c879f697623537 Mon Sep 17 00:00:00
>>> 2001
>>> From: jb <jb@JB-PC>
>>> Date: Mon, 26 Dec 2016 15:03:41 +0100
>>> Subject: [PATCH] Adding sql_mode=CONCAT_NULL_YIELDS_NULL_OFF which 
>>> is added by
>>
>> I'm not sure about _OFF at the end. It sounds confusing.
>>
>>
>> Perhaps CONCAT_NULL_YIELDS_NOT_NULL would be a better name.
>>
>>
>>>  default to sql_mode=ORACLE. Concatenating a zero-length character 
>>> string with  another operand always results in the other operand, so 
>>> null can result only  from the concatenation of two null strings.
>>>
>>> ---
>>>  include/my_bit.h                                   |  5 +++
>>>  .../suite/compat/oracle/r/func_concat.result       | 16 ++++++++
>>>  mysql-test/suite/compat/oracle/t/func_concat.test  | 17 ++++++++
>>>  scripts/mysql_system_tables.sql                    |  4 +-
>>>  scripts/mysql_system_tables_fix.sql                |  3 +-
>>>  sql/event_db_repository.cc                         |  2 +-
>>>  sql/item_strfunc.cc                                | 47 +++++++++++++++++-----
>>>  sql/sp.cc                                          |  2 +-
>>>  sql/sql_class.h                                    |  1 +
>>>  sql/sys_vars.cc                                    |  5 ++-
>>>  sql/sys_vars.ic                                    |  8 ++--
>>>  11 files changed, 89 insertions(+), 21 deletions(-)  create mode
>>> 100644 mysql-test/suite/compat/oracle/r/func_concat.result
>>>  create mode 100644 
>>> mysql-test/suite/compat/oracle/t/func_concat.test
>>>
>>> diff --git a/include/my_bit.h b/include/my_bit.h index
>>> a50403c..4918815 100644
>>> --- a/include/my_bit.h
>>> +++ b/include/my_bit.h
>>> @@ -130,6 +130,11 @@ static inline uint32 my_set_bits(int n)
>>>    return (((1UL << (n - 1)) - 1) << 1) | 1;  }
>>>  
>>> +static inline uint64 my_set_bits64(int n) {
>>> +  return (((1ULL << (n - 1)) - 1) << 1) | 1; }
>>> +
>>>  C_MODE_END
>>>  
>>>  #endif /* MY_BIT_INCLUDED */
>>> diff --git a/mysql-test/suite/compat/oracle/r/func_concat.result
>>> b/mysql-test/suite/compat/oracle/r/func_concat.result
>>> new file mode 100644
>>> index 0000000..d055192
>>> --- /dev/null
>>> +++ b/mysql-test/suite/compat/oracle/r/func_concat.result
>>> @@ -0,0 +1,16 @@
>>> +SET sql_mode=ORACLE;
>>> +SELECT 'a'||'b';
>>> +'a'||'b'
>>> +ab
>>> +SELECT 'a'||'b'||NULL;
>>> +'a'||'b'||NULL
>>> +ab
>>> +SELECT NULL||'b'||NULL;
>>> +NULL||'b'||NULL
>>> +b
>>> +SELECT NULL||NULL||'c';
>>> +NULL||NULL||'c'
>>> +c
>>> +SELECT NULL||NULL;
>>> +NULL||NULL
>>> +NULL
>>
>>
>> Can you please add tests with table fields?
>> The implementation of Item_func_concat:val_str() use args[x]->const_item(). So using non-const arguments would improve coverage.
>>
>> Something like this would be nice:
>>
>> CREATE TABLE t1 (a VARCHAR(10), b VARCHAR(10), c VARCHAR(10)); INSERT 
>> INTO t1 VALUES (NULL,NULL,NULL); INSERT INTO t1 VALUES 
>> ('a',NULL,NULL); INSERT INTO t1 VALUES (NULL,'b',NULL); INSERT INTO 
>> t1 VALUES (NULL,NULL,'c'); INSERT INTO t1 VALUES ('a','b',NULL); 
>> INSERT INTO t1 VALUES (NULL,'b','c'); INSERT INTO t1 VALUES 
>> ('a',NULL,'c'); SELECT a||b||c FROM t1; DROP TABLE t1;
>>
>>
>>
>>> diff --git a/mysql-test/suite/compat/oracle/t/func_concat.test
>>> b/mysql-test/suite/compat/oracle/t/func_concat.test
>>> new file mode 100644
>>> index 0000000..8d84707
>>> --- /dev/null
>>> +++ b/mysql-test/suite/compat/oracle/t/func_concat.test
>>> @@ -0,0 +1,17 @@
>>> +#
>>> +# Testing CONCAT with null value
>>> +#
>>> +
>>> +SET sql_mode=ORACLE;
>>> +
>>> +SELECT 'a'||'b';
>>> +
>>> +SELECT 'a'||'b'||NULL;
>>> +
>>> +SELECT NULL||'b'||NULL;
>>> +
>>> +SELECT NULL||NULL||'c';
>>> +
>>> +SELECT NULL||NULL;
>>> +
>>> +
>>> diff --git a/scripts/mysql_system_tables.sql 
>>> b/scripts/mysql_system_tables.sql index 7b61416..eb2c97f 100644
>>> --- a/scripts/mysql_system_tables.sql
>>> +++ b/scripts/mysql_system_tables.sql
>>> @@ -80,7 +80,7 @@ CREATE TABLE IF NOT EXISTS time_zone_transition_type (   Time_zone_id int unsign
>>>  
>>>  CREATE TABLE IF NOT EXISTS time_zone_leap_second (   Transition_time bigint signed NOT NULL, Correction int signed NOT NULL, PRIMARY KEY TranTime (Transition_time) ) engine=MyISAM CHARACTER SET utf8   comment='Leap seconds information for time zones';
>>>  
>>> -CREATE TABLE IF NOT EXISTS proc (db char(64) collate utf8_bin 
>>> DEFAULT '' NOT NULL, name char(64) DEFAULT '' NOT NULL, type
>>> enum('FUNCTION','PROCEDURE') NOT NULL, specific_name char(64) 
>>> DEFAULT '' NOT NULL, language enum('SQL') DEFAULT 'SQL' NOT NULL, 
>>> sql_data_access enum( 'CONTAINS_SQL', 'NO_SQL', 'READS_SQL_DATA',
>>> 'MODIFIES_SQL_DATA') DEFAULT 'CONTAINS_SQL' NOT NULL, 
>>> is_deterministic
>>> enum('YES','NO') DEFAULT 'NO' NOT NULL, security_type
>>> enum('INVOKER','DEFINER') DEFAULT 'DEFINER' NOT NULL, param_list 
>>> blob NOT NULL, returns longblob NOT NULL, body longblob NOT NULL, 
>>> definer
>>> char(141) collate utf8_bin DEFAULT '' NOT NULL, created timestamp 
>>> NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
>>> modified timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', sql_mode 
>>> set( 'REAL_AS_FLOAT', 'PIPES_AS_CONCAT', 'ANSI_QUOTES', 
>>> 'IGNORE_SPACE', 'IGNORE_BAD_TABLE_OPTIONS', 'ONLY_FULL_GROUP_BY', 
>>> 'NO_UNSIGNED_SUBTRACTION', 'NO_DIR_IN_CREATE', 'POSTGRESQL', 
>>> 'ORACLE', 'MSSQL', 'DB2', 'MAXDB', 'NO_KEY_OPTIONS', 
>>> 'NO_TABLE_OPTIONS', 'NO_FIELD_OPTIONS', 'MYSQL323', 'MYSQL40', 
>>> 'ANSI', 'NO_AUTO_VALUE_ON_ZERO', 'NO_BACKSLASH_ESCAPES', 
>>> 'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 'NO_ZERO_IN_DATE', 
>>> 'NO_ZERO_DATE', 'INVALID_DATES', 'ERROR_FOR_DIVISION_BY_ZERO', 
>>> 'TRADITIONAL', 'NO_AUTO_CREATE_USER', 'HIGH_NOT_PRECEDENCE', 
>>> 'NO_ENGINE_SUBSTITUTION', 'PAD_CHAR_TO_FULL_LENGTH') DEFAULT '' NOT 
>>> NULL, comment text collate utf8_bin NOT NULL, character_set_client
>>> char(32) collate utf8_bin, collation_connection char(32) collate 
>>> utf8_bin, db_collation char(32) collate utf8_bin, body_utf8 
>>> longblob, PRIMARY KEY (db,name,type)) engine=MyISAM character set 
>>> utf8 comment='Stored Procedures';
>>> +CREATE TABLE IF NOT EXISTS proc (db char(64) collate utf8_bin 
>>> +DEFAULT '' NOT NULL, name char(64) DEFAULT '' NOT NULL, type
>>> +enum('FUNCTION','PROCEDURE') NOT NULL, specific_name char(64) 
>>> +DEFAULT '' NOT NULL, language enum('SQL') DEFAULT 'SQL' NOT NULL, 
>>> +sql_data_access enum( 'CONTAINS_SQL', 'NO_SQL', 'READS_SQL_DATA',
>>> +'MODIFIES_SQL_DATA') DEFAULT 'CONTAINS_SQL' NOT NULL, 
>>> +is_deterministic enum('YES','NO') DEFAULT 'NO' NOT NULL, 
>>> +security_type enum('INVOKER','DEFINER') DEFAULT 'DEFINER' NOT NULL, 
>>> +param_list blob NOT NULL, returns longblob NOT NULL, body longblob 
>>> +NOT NULL, definer char(141) collate utf8_bin DEFAULT '' NOT NULL, 
>>> +created timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE 
>>> +CURRENT_TIMESTAMP, modified timestamp NOT NULL DEFAULT '0000-00-00 
>>> +00:00:00', sql_mode set( 'REAL_AS_FLOAT', 'PIPES_AS_CONCAT', 
>>> +'ANSI_QUOTES', 'IGNORE_SPACE', 'IGNORE_BAD_TABLE_OPTIONS', 
>>> +'ONLY_FULL_GROUP_BY', 'NO_UNSIGNED_SUBTRACTION', 
>>> +'NO_DIR_IN_CREATE', 'POSTGRESQL', 'ORACLE', 'MSSQL', 'DB2', 
>>> +'MAXDB', 'NO_KEY_OPTIONS', 'NO_TABLE_OPTIONS', 'NO_FIELD_OPTIONS', 
>>> +'MYSQL323', 'MYSQL40', 'ANSI', 'NO_AUTO_VALUE_ON_ZERO', 
>>> +'NO_BACKSLASH_ESCAPES', 'STRICT_TRANS_TABLES', 'STRICT_ALL_TABLES', 
>>> +'NO_ZERO_IN_DATE', 'NO_ZERO_DATE', 'INVALID_DATES', 
>>> +'ERROR_FOR_DIVISION_BY_ZERO', 'TRADITIONAL', 'NO_AUTO_CREATE_USER', 
>>> +'HIGH_NOT_PRECEDENCE', 'NO_ENGINE_SUBSTITUTION',
>>> +'PAD_CHAR_TO_FULL_LENGTH','CONCAT_NULL_YIELDS_NULL_OFF') DEFAULT '' 
>>> +NOT NULL, comment text collate utf8_bin NOT NULL, 
>>> +character_set_client char(32) collate utf8_bin, 
>>> +collation_connection
>>> +char(32) collate utf8_bin, db_collation char(32) collate utf8_bin,
>>> +body_utf8 longblob, PRIMARY KEY (db,name,type)) engine=MyISAM 
>>> +character set utf8 comment='Stored Procedures';
>>>  
>>>  CREATE TABLE IF NOT EXISTS procs_priv ( Host char(60) binary DEFAULT '' NOT NULL, Db char(64) binary DEFAULT '' NOT NULL, User char(80) binary DEFAULT '' NOT NULL, Routine_name char(64) COLLATE utf8_general_ci DEFAULT '' NOT NULL, Routine_type enum('FUNCTION','PROCEDURE') NOT NULL, Grantor char(141) DEFAULT '' NOT NULL, Proc_priv set('Execute','Alter Routine','Grant') COLLATE utf8_general_ci DEFAULT '' NOT NULL, Timestamp timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (Host,Db,User,Routine_name,Routine_type), KEY Grantor (Grantor) ) engine=MyISAM CHARACTER SET utf8 COLLATE utf8_bin   comment='Procedure privileges';
>>>  
>>> @@ -101,7 +101,7 @@ PREPARE stmt FROM @str;  EXECUTE stmt;  DROP 
>>> PREPARE stmt;
>>>  
>>> -CREATE TABLE IF NOT EXISTS event ( db char(64) CHARACTER SET utf8 
>>> COLLATE utf8_bin NOT NULL default '', name char(64) CHARACTER SET
>>> utf8 NOT NULL default '', body longblob NOT NULL, definer char(141) 
>>> CHARACTER SET utf8 COLLATE utf8_bin NOT NULL default '', execute_at 
>>> DATETIME default NULL, interval_value int(11) default NULL, 
>>> interval_field 
>>> ENUM('YEAR','QUARTER','MONTH','DAY','HOUR','MINUTE','WEEK','SECOND','
>>> M
>>> ICROSECOND','YEAR_MONTH','DAY_HOUR','DAY_MINUTE','DAY_SECOND','HOUR_
>>> M
>>> I
>>> NUTE','HOUR_SECOND','MINUTE_SECOND','DAY_MICROSECOND','HOUR_MICROSEC
>>> O
>>> N
>>> D','MINUTE_MICROSECOND','SECOND_MICROSECOND') default NULL, created 
>>> TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE 
>>> CURRENT_TIMESTAMP, modified TIMESTAMP NOT NULL DEFAULT '0000-00-00 
>>> 00:00:00', last_executed DATETIME default NULL, starts DATETIME 
>>> default NULL, ends DATETIME default NULL, status
>>> ENUM('ENABLED','DISABLED','SLAVESIDE_DISABLED') NOT NULL default 
>>> 'ENABLED', on_completion ENUM('DROP','PRESERVE') NOT NULL default 
>>> 'DROP', sql_mode 
>>> set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','
>>> I
>>> G
>>> NORE_BAD_TABLE_OPTIONS','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION'
>>> ,'NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_
>>> K
>>> E
>>> Y_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40'
>>> ,
>>> 'ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_
>>> T
>>> A
>>> BLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_
>>> D
>>> A
>>> TES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER'
>>> ,
>>> 'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LEN
>>> G
>>> T
>>> H') DEFAULT '' NOT NULL, comment char(64) CHARACTER SET utf8 COLLATE 
>>> utf8_bin NOT NULL default '', originator INTEGER UNSIGNED NOT NULL, 
>>> time_zone char(64) CHARACTER SET latin1 NOT NULL DEFAULT 'SYSTEM', 
>>> character_set_client char(32) collate utf8_bin, collation_connection
>>> char(32) collate utf8_bin, db_collation char(32) collate utf8_bin,
>>> body_utf8 longblob, PRIMARY KEY (db, name) ) ENGINE=MyISAM DEFAULT
>>> CHARSET=utf8 COMMENT 'Events';
>>> +CREATE TABLE IF NOT EXISTS event ( db char(64) CHARACTER SET utf8 
>>> +COLLATE utf8_bin NOT NULL default '', name char(64) CHARACTER SET
>>> +utf8 NOT NULL default '', body longblob NOT NULL, definer char(141) 
>>> +CHARACTER SET utf8 COLLATE utf8_bin NOT NULL default '', execute_at 
>>> +DATETIME default NULL, interval_value int(11) default NULL, 
>>> +interval_field 
>>> +ENUM('YEAR','QUARTER','MONTH','DAY','HOUR','MINUTE','WEEK','SECOND','
>>> +MICROSECOND','YEAR_MONTH','DAY_HOUR','DAY_MINUTE','DAY_SECOND','HOU
>>> +R
>>> +_
>>> +MINUTE','HOUR_SECOND','MINUTE_SECOND','DAY_MICROSECOND','HOUR_MICRO
>>> +S
>>> +E
>>> +COND','MINUTE_MICROSECOND','SECOND_MICROSECOND') default NULL, 
>>> +created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE 
>>> +CURRENT_TIMESTAMP, modified TIMESTAMP NOT NULL DEFAULT '0000-00-00 
>>> +00:00:00', last_executed DATETIME default NULL, starts DATETIME 
>>> +default NULL, ends DATETIME default NULL, status
>>> +ENUM('ENABLED','DISABLED','SLAVESIDE_DISABLED') NOT NULL default 
>>> +'ENABLED', on_completion ENUM('DROP','PRESERVE') NOT NULL default 
>>> +'DROP', sql_mode 
>>> +set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','
>>> +I
>>> +GNORE_BAD_TABLE_OPTIONS','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACT
>>> +I
>>> +O
>>> +N','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','
>>> +N
>>> +O
>>> +_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYS
>>> +Q
>>> +L
>>> +40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_T
>>> +R
>>> +A
>>> +NS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','IN
>>> +V
>>> +A
>>> +LID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREA
>>> +T
>>> +E
>>> +_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_
>>> +F
>>> +U
>>> +LL_LENGTH','CONCAT_NULL_YIELDS_NULL_OFF') DEFAULT '' NOT NULL, 
>>> +comment char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL 
>>> +default '', originator INTEGER UNSIGNED NOT NULL, time_zone 
>>> +char(64) CHARACTER SET latin1 NOT NULL DEFAULT 'SYSTEM', 
>>> +character_set_client
>>> +char(32) collate utf8_bin, collation_connection char(32) collate 
>>> +utf8_bin, db_collation char(32) collate utf8_bin, body_utf8 
>>> +longblob, PRIMARY KEY (db, name) ) ENGINE=MyISAM DEFAULT
>>> +CHARSET=utf8 COMMENT 'Events';
>>>  
>>>  SET @create_innodb_table_stats="CREATE TABLE IF NOT EXISTS innodb_table_stats (
>>>  	database_name			VARCHAR(64) NOT NULL,
>>> diff --git a/scripts/mysql_system_tables_fix.sql
>>> b/scripts/mysql_system_tables_fix.sql
>>> index ea1059c..b3c0ce9 100644
>>> --- a/scripts/mysql_system_tables_fix.sql
>>> +++ b/scripts/mysql_system_tables_fix.sql
>>> @@ -442,7 +442,8 @@ ALTER TABLE proc MODIFY name char(64) DEFAULT '' NOT NULL,
>>>                              'NO_AUTO_CREATE_USER',
>>>                              'HIGH_NOT_PRECEDENCE',
>>>                              'NO_ENGINE_SUBSTITUTION',
>>> -                            'PAD_CHAR_TO_FULL_LENGTH'
>>> +                            'PAD_CHAR_TO_FULL_LENGTH',
>>> +                            'CONCAT_NULL_YIELDS_NULL_OFF'
>>>                              ) DEFAULT '' NOT NULL,
>>>                   DEFAULT CHARACTER SET utf8;
>>>  
>>> diff --git a/sql/event_db_repository.cc b/sql/event_db_repository.cc 
>>> index 9de55c4..c279a85 100644
>>> --- a/sql/event_db_repository.cc
>>> +++ b/sql/event_db_repository.cc
>>> @@ -123,7 +123,7 @@ const TABLE_FIELD_TYPE event_table_fields[ET_FIELD_COUNT] =
>>>      "'ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES',"
>>>      "'STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES',"
>>>      "'ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER',"
>>> -    "'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH')") },
>>> +    
>>> + "'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_
>>> + L
>>> + E
>>> + NGTH','CONCAT_NULL_YIELDS_NULL_OFF')") },
>>>      {NULL, 0}
>>>    },
>>>    {
>>> diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc index 
>>> fe1c470..7b22f4b 100644
>>> --- a/sql/item_strfunc.cc
>>> +++ b/sql/item_strfunc.cc
>>> @@ -619,19 +619,42 @@ String *Item_func_concat::val_str(String *str)
>>>    DBUG_ASSERT(fixed == 1);
>>>    String *res,*res2,*use_as_buff;
>>>    uint i;
>>> -  bool is_const= 0;
>>> +  bool is_const = 0;
>>
>> Please follow the MariaDB coding style:
>>
>> 1. In assignment operator:
>> - there is no space before "="
>> - there is one space after "=".
>>
>> So the above line "bool is_const= 0;" should not be modified.
>>
>> 2. Don't use tabs, use spaces instead.
>>
>> 3. There should not be trailing white spaces.
>>    Please use "git diff --check".
>>
>>
>> Note, the old code may not always be following the coding style.
>> So don't be confused :) Some lines are old enough, older than the coding style policy.
>>
>> Please make sure that all new and modified line follows the coding style.
>>
>>
>>> +  uint firstarg = 0;
>>> +  uint nextarg = 1;
>>
>> These two variables basically repeat each other, and repeat "i".
>>
>> Also, I noticed that args[0]->val_str() is called twice.
>>
>> One time in the "// Search first non null argument" loop, and then before the "for (i= nextarg; i < arg_count ; i++)" again.
>>
>> I suggest to remove firstarg and nextarg and always use "i" instead, and to make sure that val_str() is not called twice for the same argument.
>>
>>
>>
>>>  
>>> -  null_value=0;
>>> -  if (!(res=args[0]->val_str(str)))
>>> +  if (current_thd->variables.sql_mode &
>>> + MODE_CONCAT_NULL_YIELDS_NULL_OFF)
>>
>> current_thd is a heavy function.
>> It's better to avoid its execution per row.
>> Please add a new boolean member and initialize it to false in constructors:
>>
>>
>> class Item_func_concat :public Item_str_func {
>>   m_null_yierds_not_null;
>>   String tmp_value;
>> public:
>>   Item_func_concat(THD *thd, List<Item> &list):
>>     Item_str_func(thd, list),
>>     m_null_yield_not_null(false)
>>   {}
>>   Item_func_concat(THD *thd, Item *a, Item *b):
>>     Item_str_func(thd, a, b),
>>     m_null_yield_not_null(false)
>>   {}
>> ...
>> };
>>
>>
>> and then set it according to sql_mode in fix_length_and_dec():
>>
>>
>>
>> void Item_func_concat::fix_length_and_dec()
>> {
>>   m_null_yields_not_null= current_thd->variables.sql_mode & MODE_CONCAT_NULL_YIELDS_NULL_OFF;
>>   ...
>> }
>>
>>
>> After this, we change all tests like:
>>
>>    if (current_thd->variables.sql_mode &
>> MODE_CONCAT_NULL_YIELDS_NULL_OFF)
>>
>> to
>>
>>   if (m_null_yields_not_null)
>>
>>
>>> +  {
>>> +    // Search first non null argument
>>> +    i = 0;
>>> +    while (!(res = args[i]->val_str(str)))
>>> +    {
>>> +      if (++i == arg_count)
>>> +        break;
>>> +    }
>>> +    if (res)
>>> +    {
>>> +      firstarg=i++;
>>> +      nextarg = i;
>>> +    }
>>> +  }
>>
>> I find something like this more readable:
>>
>> ...
>>   // Search first non null argument
>>   for (i= 0; i < arg_count; i++)
>>   {
>>     if ((res= args[i]->val_str(str))
>>       break;
>>   }
>>   if (i == arg_count)
>>     goto null;
>> ...
>>
>>
>>> +
>>> +	null_value = 0;
>>> +	if (!(res = args[firstarg]->val_str(str)))
>>
>> There are tabs in the above two lines. Please use spaces.
>>
>>
>>>      goto null;
>>> -  use_as_buff= &tmp_value;
>>> -  is_const= args[0]->const_item();
>>> -  for (i=1 ; i < arg_count ; i++)
>>> +  use_as_buff = &tmp_value;
>>> +  is_const = args[firstarg]->const_item();
>>> + 
>>> +  for (i= nextarg; i < arg_count ; i++)
>>>    {
>>>      if (res->length() == 0)
>>>      {
>>> -      if (!(res=args[i]->val_str(str)))
>>> -	goto null;
>>> +      if (!(res = args[i]->val_str(str)))
>>> +      {
>>> +        if (current_thd->variables.sql_mode &
>>> + MODE_CONCAT_NULL_YIELDS_NULL_OFF)
>>
>>   if (m_null_yields_not_null)
>>
>>> +          continue;
>>> +        goto null;
>>> +      }
>>>        /*
>>>         CONCAT accumulates its result in the result of its the first
>>>         non-empty argument. Because of this we need is_const to be 
>>> @@
>>> -641,8 +664,12 @@ String *Item_func_concat::val_str(String *str)
>>>      }
>>>      else
>>>      {
>>> -      if (!(res2=args[i]->val_str(use_as_buff)))
>>> -	goto null;
>>> +    if (!(res2 = args[i]->val_str(use_as_buff)))
>>> +    {
>>> +      if (current_thd->variables.sql_mode &
>>> + MODE_CONCAT_NULL_YIELDS_NULL_OFF)
>>
>>   if (m_null_yields_not_null)
>>
>>
>>> +        continue;
>>> +      goto null;
>>> +    }
>>>        if (res2->length() == 0)
>>>  	continue;
>>>        if (res->length()+res2->length() > diff --git a/sql/sp.cc 
>>> b/sql/sp.cc index eb542a6..288b7a9 100644
>>> --- a/sql/sp.cc
>>> +++ b/sql/sp.cc
>>> @@ -130,7 +130,7 @@ TABLE_FIELD_TYPE proc_table_fields[MYSQL_PROC_FIELD_COUNT] =
>>>      "'ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES',"
>>>      "'STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES',"
>>>      "'ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER',"
>>> -    "'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH')") },
>>> +    
>>> + "'HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_
>>> + L
>>> + E
>>> + NGTH','CONCAT_NULL_YIELDS_NULL_OFF')") },
>>>      { NULL, 0 }
>>>    },
>>>    {
>>> diff --git a/sql/sql_class.h b/sql/sql_class.h index 
>>> 6f8e884..c754092
>>> 100644
>>> --- a/sql/sql_class.h
>>> +++ b/sql/sql_class.h
>>> @@ -139,6 +139,7 @@ enum enum_binlog_row_image {
>>>  #define MODE_HIGH_NOT_PRECEDENCE        (1ULL << 29)
>>>  #define MODE_NO_ENGINE_SUBSTITUTION     (1ULL << 30)
>>>  #define MODE_PAD_CHAR_TO_FULL_LENGTH    (1ULL << 31)
>>> +#define MODE_CONCAT_NULL_YIELDS_NULL_OFF (1ULL << 32)
>>>  
>>>  /* Bits for different old style modes */
>>>  #define OLD_MODE_NO_DUP_KEY_WARNINGS_WITH_IGNORE	(1 << 0)
>>> diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc index
>>> 27e6463..c51b1de3
>>> 100644
>>> --- a/sql/sys_vars.cc
>>> +++ b/sql/sys_vars.cc
>>> @@ -3032,7 +3032,8 @@ export sql_mode_t expand_sql_mode(sql_mode_t sql_mode)
>>>      sql_mode|= (MODE_PIPES_AS_CONCAT | MODE_ANSI_QUOTES |
>>>                  MODE_IGNORE_SPACE |
>>>                  MODE_NO_KEY_OPTIONS | MODE_NO_TABLE_OPTIONS |
>>> -                MODE_NO_FIELD_OPTIONS | MODE_NO_AUTO_CREATE_USER);
>>> +                MODE_NO_FIELD_OPTIONS | MODE_NO_AUTO_CREATE_USER |
>>> +                MODE_CONCAT_NULL_YIELDS_NULL_OFF);
>>>    if (sql_mode & MODE_MSSQL)
>>>      sql_mode|= (MODE_PIPES_AS_CONCAT | MODE_ANSI_QUOTES |
>>>                  MODE_IGNORE_SPACE | @@ -3097,7 +3098,7 @@ static 
>>> const char *sql_mode_names[]=
>>>    "STRICT_ALL_TABLES", "NO_ZERO_IN_DATE", "NO_ZERO_DATE",
>>>    "ALLOW_INVALID_DATES", "ERROR_FOR_DIVISION_BY_ZERO", "TRADITIONAL",
>>>    "NO_AUTO_CREATE_USER", "HIGH_NOT_PRECEDENCE", 
>>> "NO_ENGINE_SUBSTITUTION",
>>> -  "PAD_CHAR_TO_FULL_LENGTH",
>>> +  "PAD_CHAR_TO_FULL_LENGTH","CONCAT_NULL_YIELDS_NULL_OFF",
>>>    0
>>>  };
>>>  
>>> diff --git a/sql/sys_vars.ic b/sql/sys_vars.ic index 
>>> c7f148a..fc93534
>>> 100644
>>> --- a/sql/sys_vars.ic
>>> +++ b/sql/sys_vars.ic
>>> @@ -1228,7 +1228,7 @@ class Sys_var_flagset: public Sys_var_typelib
>>>      global_var(ulonglong)= def_val;
>>>      SYSVAR_ASSERT(typelib.count > 1);
>>>      SYSVAR_ASSERT(typelib.count <= 65);
>>> -    SYSVAR_ASSERT(def_val < my_set_bits(typelib.count));
>>> +    SYSVAR_ASSERT(def_val < my_set_bits64(typelib.count));
>>>      SYSVAR_ASSERT(strcmp(values[typelib.count-1], "default") == 0);
>>>      SYSVAR_ASSERT(size == sizeof(ulonglong));
>>>    }
>>> @@ -1276,7 +1276,7 @@ class Sys_var_flagset: public Sys_var_typelib
>>>      {
>>>        longlong tmp=var->value->val_int();
>>>        if ((tmp < 0 && ! var->value->unsigned_flag)
>>> -          || (ulonglong)tmp > my_set_bits(typelib.count))
>>> +          || (ulonglong)tmp > my_set_bits64(typelib.count))
>>>          return true;
>>>        else
>>>          var->save_result.ulonglong_value= tmp; @@ -1337,7 +1337,7 
>>> @@ class Sys_var_set: public Sys_var_typelib
>>>      global_var(ulonglong)= def_val;
>>>      SYSVAR_ASSERT(typelib.count > 0);
>>>      SYSVAR_ASSERT(typelib.count <= 64);
>>> -    SYSVAR_ASSERT(def_val <= my_set_bits(typelib.count));
>>> +    SYSVAR_ASSERT(def_val <= my_set_bits64(typelib.count));
>>>      SYSVAR_ASSERT(size == sizeof(ulonglong));
>>>    }
>>>    bool do_check(THD *thd, set_var *var) @@ -1375,7 +1375,7 @@ class
>>> Sys_var_set: public Sys_var_typelib
>>>      {
>>>        longlong tmp=var->value->val_int();
>>>        if ((tmp < 0 && ! var->value->unsigned_flag)
>>> -          || (ulonglong)tmp > my_set_bits(typelib.count))
>>> +          || (ulonglong)tmp > my_set_bits64(typelib.count))
>>>          return true;
>>>        else
>>>          var->save_result.ulonglong_value= tmp;
>>> --
>>> 2.6.3.windows.1


Follow ups

References