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Re: 4f070b59005: 29 Jan, MDEV-371 Unique indexes for blobs

 

Hi, Sachin!

That's generally pretty good.
But I still don't understand what you store in frm and how you
manipulate TABLE and TABLE_SHARE key lists.

Could you please explain that?

On Jan 29, Sachin Setiya wrote:

> diff --git a/mysql-test/main/long_unique.result b/mysql-test/main/long_unique.result
> new file mode 100644
> --- /dev/null
> +++ b/mysql-test/main/long_unique.result
> @@ -0,0 +1,1392 @@
> +#Structure of tests
> +#First we will check all option for
> +#table containing single unique column
> +#table containing keys like unique(a,b,c,d) etc
> +#then table containing 2 blob unique etc
> +set @allowed_packet= @@max_allowed_packet;
> +#table with single long blob column;
> +create table t1(a blob  unique );
> +insert into t1 values(1),(2),(3),(56),('sachin'),('maria'),(123456789034567891),(null),(null),(123456789034567890);
> +#blob with primary key not allowed
> +create table t2(a blob,primary key(a(10000)));
> +ERROR 42000: Specified key was too long; max key length is 1000 bytes
> +create table t3(a varchar(10000) primary key);
> +ERROR 42000: Specified key was too long; max key length is 1000 bytes
> +insert into t1 values(2);
> +ERROR 23000: Duplicate entry '2' for key 'a'
> +#table structure;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	t1
> +Non_unique	0
> +Key_name	a
> +Seq_in_index	1
> +Column_name	a
> +Collation	A
> +Cardinality	NULL
> +Sub_part	NULL
> +Packed	NULL
> +Null	YES
> +Index_type	HASH

Good.
But this also mean that HASH is a valid index type, and that one
can write

 CREATE TABLE t1 (a blob, unique (a) USING HASH)

generally, this should work. And one can write

 CREATE TABLE t1 (a blob, unique (a) USING BTREE)

and this should fail, "key too long; max key length is 1000 bytes"
Note, the syntax is already possible. You just need to handle
these cases correctly in mysql_prepare_create_table().

And if neither HASH nor BTREE is specified, it's auto-detection,
basically. For short keys it's BTREE, for long keys it's HASH.
This is already implemented by this patch :)

> +Comment	
> +Index_comment	
> +
> +MyISAM file:         DATADIR/test/t1
> +Record format:       Packed
> +Character set:       latin1_swedish_ci (8)
> +Data records:                   10  Deleted blocks:                 0
> +Recordlength:                   20
> +
> +table description:
> +Key Start Len Index   Type
> +1   12    8   multip. ulonglong NULL       
> +select * from information_schema.columns where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	COLUMN_DEFAULT	IS_NULLABLE	DATA_TYPE	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH	NUMERIC_PRECISION	NUMERIC_SCALE	DATETIME_PRECISION	CHARACTER_SET_NAME	COLLATION_NAME	COLUMN_TYPE	COLUMN_KEY	EXTRA	PRIVILEGES	COLUMN_COMMENT	IS_GENERATED	GENERATION_EXPRESSION
> +def	test	t1	a	1	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob	UNI		select,insert,update,references		NEVER	NULL
> +select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	NON_UNIQUE	INDEX_SCHEMA	INDEX_NAME	SEQ_IN_INDEX	COLUMN_NAME	COLLATION	CARDINALITY	SUB_PART	PACKED	NULLABLE	INDEX_TYPE	COMMENT	INDEX_COMMENT
> +def	test	t1	0	test	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +select   * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
> +CONSTRAINT_CATALOG	def
> +CONSTRAINT_SCHEMA	test
> +CONSTRAINT_NAME	a
> +TABLE_CATALOG	def
> +TABLE_SCHEMA	test
> +TABLE_NAME	t1
> +COLUMN_NAME	a
> +ORDINAL_POSITION	1
> +POSITION_IN_UNIQUE_CONSTRAINT	NULL
> +REFERENCED_TABLE_SCHEMA	NULL
> +REFERENCED_TABLE_NAME	NULL
> +REFERENCED_COLUMN_NAME	NULL
> +# table select we should not be able to see db_row_hash_column;
> +select * from t1 order by a;
> +a
> +NULL
> +NULL
> +1
> +123456789034567890
> +123456789034567891
> +2
> +3
> +56
> +maria
> +sachin
> +select db_row_hash_1 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +#duplicate entry test;
> +insert into t1 values(2);
> +ERROR 23000: Duplicate entry '2' for key 'a'
> +insert into t1 values('sachin');
> +ERROR 23000: Duplicate entry 'sachin' for key 'a'
> +insert into t1 values(123456789034567891);
> +ERROR 23000: Duplicate entry '123456789034567891' for key 'a'
> +select * from t1 order by a;
> +a
> +NULL
> +NULL
> +1
> +123456789034567890
> +123456789034567891
> +2
> +3
> +56
> +maria
> +sachin
> +insert into t1 values(11),(22),(33);
> +insert into t1 values(12),(22);
> +ERROR 23000: Duplicate entry '22' for key 'a'
> +select * from t1 order by a;
> +a
> +NULL
> +NULL
> +1
> +11
> +12
> +123456789034567890
> +123456789034567891
> +2
> +22
> +3
> +33
> +56
> +maria
> +sachin
> +insert into t1 values(repeat('s',4000*10)),(repeat('s',4001*10));
> +insert into t1 values(repeat('m',4000*10)),(repeat('m',4000*10));
> +ERROR 23000: Duplicate entry 'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm' for key 'a'
> +insert into t1 values(repeat('m',4001)),(repeat('m',4002));
> +truncate table t1;
> +insert into t1 values(1),(2),(3),(4),(5),(8),(7);
> +
> +MyISAM file:         DATADIR/test/t1
> +Record format:       Packed
> +Character set:       latin1_swedish_ci (8)
> +Data records:                    7  Deleted blocks:                 0
> +Recordlength:                   20
> +
> +table description:
> +Key Start Len Index   Type
> +1   12    8   multip. ulonglong NULL       
> +#now some alter commands;
> +alter table t1 add column b int;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +b	int(11)	YES		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 values(1,2);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +insert into t1 values(2,2);
> +ERROR 23000: Duplicate entry '2' for key 'a'
> +select db_row_hash_1 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +#now try to change db_row_hash_1 column;
> +alter table t1 drop column db_row_hash_1;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 add column d int , add column e int , drop column db_row_hash_1;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 modify column db_row_hash_1 int ;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column a int , add column b int, modify column db_row_hash_1 int ;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 change column db_row_hash_1 dsds int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column asd int, change column db_row_hash_1 dsds int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 drop column b , add column c int;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `c` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +#now add some column with name db_row_hash;
> +alter table t1 add column db_row_hash_1 int unique;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535)),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 values(45,1,55),(46,1,55);
> +ERROR 23000: Duplicate entry '55' for key 'db_row_hash_1'
> +insert into t1 values(45,1,55),(45,1,55);
> +ERROR 23000: Duplicate entry '45' for key 'a'
> +alter table t1 add column db_row_hash_2 int, add column db_row_hash_3 int;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +c	int(11)	YES		NULL	
> +db_row_hash_1	int(11)	YES	UNI	NULL	
> +db_row_hash_2	int(11)	YES		NULL	
> +db_row_hash_3	int(11)	YES		NULL	
> +#this should also drop the unique index ;
> +alter table t1 drop column a;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +#add column with unique index on blob ;
> +alter table t1 add column a blob unique;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  `a` blob DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +# try to change the blob unique name;
> +#this will change index to b tree;
> +alter table t1 change column a aa blob ;

eh, the comment is wrong. Your old code
changed the column to int, that was indeed changing the
index to a btree. But now you simply rename the blob.
the index is not changed to btree anymore.

> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  `aa` blob DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `a` (`aa`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	aa	A	NULL	NULL	NULL	YES	HASH		
> +# try to change the blob unique datatype;
> +#this will change index to b tree;
> +alter table t1 modify  column aa  int ;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  `aa` int(11) DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `a` (`aa`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	aa	A	NULL	NULL	NULL	YES	BTREE		
> +alter table t1 add column clm blob unique;
> +#try changing the name ;
> +alter table t1 change column clm clm_changed blob;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  `aa` int(11) DEFAULT NULL,
> +  `clm_changed` blob DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `a` (`aa`),
> +  UNIQUE KEY `clm` (`clm_changed`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	aa	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	clm	1	clm_changed	A	NULL	NULL	NULL	YES	HASH		
> +#now drop the unique key;
> +alter table t1 drop key clm;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `c` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  `aa` int(11) DEFAULT NULL,
> +  `clm_changed` blob DEFAULT NULL,
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `a` (`aa`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	aa	A	NULL	NULL	NULL	YES	BTREE		
> +drop table t1;
> +create table t1 (a TEXT CHARSET latin1 COLLATE latin1_german2_ci unique);
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	text	YES	UNI	NULL	
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +insert into t1 values ('ae');
> +insert into t1 values ('AE');
> +ERROR 23000: Duplicate entry 'AE' for key 'a'
> +insert  into t1 values ('Ä');
> +drop table t1;
> +create table t1 (a int primary key, b blob unique);
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	int(11)	NO	PRI	NULL	
> +b	blob	YES	UNI	NULL	
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	PRIMARY	1	a	A	0	NULL	NULL		BTREE		
> +t1	0	b	1	b	A	NULL	NULL	NULL	YES	HASH		
> +insert into t1 values(1,1),(2,2),(3,3);
> +insert into t1 values(1,1);
> +ERROR 23000: Duplicate entry '1' for key 'b'
> +insert into t1 values(7,1);
> +ERROR 23000: Duplicate entry '1' for key 'b'
> +drop table t1;
> +#table with multiple  long blob column and varchar text column ;
> +create table t1(a blob unique, b int , c blob unique , d text unique , e varchar(3000) unique);
> +insert into t1 values(1,2,3,4,5),(2,11,22,33,44),(3111,222,333,444,555),(5611,2222,3333,4444,5555),
> +('sachin',341,'fdf','gfgfgfg','hghgr'),('maria',345,'frter','dasd','utyuty'),
> +(123456789034567891,353534,53453453453456,64565464564564,45435345345345),
> +(123456789034567890,43545,657567567567,78967657567567,657567567567567676);
> +#table structure;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +b	int(11)	YES		NULL	
> +c	blob	YES	UNI	NULL	
> +d	text	YES	UNI	NULL	
> +e	varchar(3000)	YES	UNI	NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`),
> +  UNIQUE KEY `c` (`c`),
> +  UNIQUE KEY `d` (`d`),
> +  UNIQUE KEY `e` (`e`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	d	1	d	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	HASH		
> +
> +MyISAM file:         DATADIR/test/t1
> +Record format:       Packed
> +Character set:       latin1_swedish_ci (8)
> +Data records:                    8  Deleted blocks:                 0
> +Recordlength:                 3072
> +
> +table description:
> +Key Start Len Index   Type
> +1   3063  8   multip. ulonglong NULL       
> +2   3055  8   multip. ulonglong NULL       
> +3   3047  8   multip. ulonglong NULL       
> +4   3039  8   multip. ulonglong NULL       
> +select * from information_schema.columns where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	COLUMN_DEFAULT	IS_NULLABLE	DATA_TYPE	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH	NUMERIC_PRECISION	NUMERIC_SCALE	DATETIME_PRECISION	CHARACTER_SET_NAME	COLLATION_NAME	COLUMN_TYPE	COLUMN_KEY	EXTRA	PRIVILEGES	COLUMN_COMMENT	IS_GENERATED	GENERATION_EXPRESSION
> +def	test	t1	a	1	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob	UNI		select,insert,update,references		NEVER	NULL
> +def	test	t1	b	2	NULL	YES	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11)			select,insert,update,references		NEVER	NULL
> +def	test	t1	c	3	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob	UNI		select,insert,update,references		NEVER	NULL
> +def	test	t1	d	4	NULL	YES	text	65535	65535	NULL	NULL	NULL	latin1	latin1_swedish_ci	text	UNI		select,insert,update,references		NEVER	NULL
> +def	test	t1	e	5	NULL	YES	varchar	3000	3000	NULL	NULL	NULL	latin1	latin1_swedish_ci	varchar(3000)	UNI		select,insert,update,references		NEVER	NULL
> +select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	NON_UNIQUE	INDEX_SCHEMA	INDEX_NAME	SEQ_IN_INDEX	COLUMN_NAME	COLLATION	CARDINALITY	SUB_PART	PACKED	NULLABLE	INDEX_TYPE	COMMENT	INDEX_COMMENT
> +def	test	t1	0	test	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	d	1	d	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	e	1	e	A	NULL	NULL	NULL	YES	HASH		
> +select * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
> +CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_TABLE_SCHEMA	REFERENCED_TABLE_NAME	REFERENCED_COLUMN_NAME
> +def	test	a	def	test	t1	a	1	NULL	NULL	NULL	NULL
> +def	test	c	def	test	t1	c	1	NULL	NULL	NULL	NULL
> +def	test	d	def	test	t1	d	1	NULL	NULL	NULL	NULL
> +def	test	e	def	test	t1	e	1	NULL	NULL	NULL	NULL
> +#table select we should not be able to see db_row_hash_1 column;
> +select * from t1 order by a;
> +a	b	c	d	e
> +1	2	3	4	5
> +123456789034567890	43545	657567567567	78967657567567	657567567567567676
> +123456789034567891	353534	53453453453456	64565464564564	45435345345345
> +2	11	22	33	44
> +3111	222	333	444	555
> +5611	2222	3333	4444	5555
> +maria	345	frter	dasd	utyuty
> +sachin	341	fdf	gfgfgfg	hghgr
> +select db_row_hash_1 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +select db_row_hash_2 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_2' in 'field list'
> +select db_row_hash_3 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_3' in 'field list'
> +#duplicate entry test;
> +insert into t1 values(21,2,3,42,51);
> +ERROR 23000: Duplicate entry '3' for key 'c'
> +insert into t1 values('sachin',null,null,null,null);
> +ERROR 23000: Duplicate entry 'sachin' for key 'a'
> +insert into t1 values(1234567890345671890,4353451,6575675675617,789676575675617,657567567567567676);
> +ERROR 23000: Duplicate entry '657567567567567676' for key 'e'
> +select * from t1 order by a;
> +a	b	c	d	e
> +1	2	3	4	5
> +123456789034567890	43545	657567567567	78967657567567	657567567567567676
> +123456789034567891	353534	53453453453456	64565464564564	45435345345345
> +2	11	22	33	44
> +3111	222	333	444	555
> +5611	2222	3333	4444	5555
> +maria	345	frter	dasd	utyuty
> +sachin	341	fdf	gfgfgfg	hghgr
> +insert into t1 values(repeat('s',4000*10),100,repeat('s',4000*10),repeat('s',4000*10),
> +repeat('s',400)),(repeat('s',4001*10),1000,repeat('s',4001*10),repeat('s',4001*10),
> +repeat('s',2995));
> +insert into t1 values(repeat('m',4000*11),10,repeat('s',4000*11),repeat('s',4000*11),repeat('s',2995));
> +ERROR 23000: Duplicate entry 'ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss' for key 'e'
> +truncate table t1;
> +insert into t1 values(1,2,3,4,5),(2,11,22,33,44),(3111,222,333,444,555),(5611,2222,3333,4444,5555);
> +#now some alter commands;
> +alter table t1 add column f int;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +b	int(11)	YES		NULL	
> +c	blob	YES	UNI	NULL	
> +d	text	YES	UNI	NULL	
> +e	varchar(3000)	YES	UNI	NULL	
> +f	int(11)	YES		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535)),
> +  UNIQUE KEY `c` (`c`(65535)),
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +#unique key should not break;
> +insert into t1 values(1,2,3,4,5,6);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +select db_row_hash_1 , db_row_hash_2, db_row_hash_3 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +#now try to change db_row_hash_1 column;
> +alter table t1 drop column db_row_hash_1, drop column db_row_hash_2, drop column db_row_hash_3;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 add column dg int , add column ef int , drop column db_row_hash_1;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 modify column db_row_hash_1 int , modify column db_row_hash_2 int, modify column db_row_hash_3 int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column ar int , add column rb int, modify column db_row_hash_1 int , modify column db_row_hash_3 int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 change column db_row_hash_1 dsds int , change column  db_row_hash_2  dfdf int , change column db_row_hash_3 gdfg int ;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column asd int, drop column a, change column db_row_hash_1 dsds int, change db_row_hash_3 fdfdfd int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 drop column b , add column g int;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535)),
> +  UNIQUE KEY `c` (`c`(65535)),
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +#now add some column with name db_row_hash;
> +alter table t1 add column db_row_hash_1 int unique;
> +alter table t1 add column db_row_hash_2 int unique;
> +alter table t1 add column db_row_hash_3 int unique;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_3` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535)),
> +  UNIQUE KEY `c` (`c`(65535)),
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
> +  UNIQUE KEY `db_row_hash_3` (`db_row_hash_3`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +alter table t1 add column db_row_hash_7 int, add column db_row_hash_5 int , add column db_row_hash_4 int ;
> +alter table t1 drop column db_row_hash_7,drop column db_row_hash_3, drop column db_row_hash_4;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +c	blob	YES	UNI	NULL	
> +d	text	YES	UNI	NULL	
> +e	varchar(3000)	YES	UNI	NULL	
> +f	int(11)	YES		NULL	
> +g	int(11)	YES		NULL	
> +db_row_hash_1	int(11)	YES	UNI	NULL	
> +db_row_hash_2	int(11)	YES	UNI	NULL	
> +db_row_hash_5	int(11)	YES		NULL	
> +#this should not break anything;
> +insert into t1 values(1,2,3,4,5,6,23,5,6);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +#this should also drop the unique index;
> +alter table t1 drop column a, drop column c;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	d	1	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_2	1	db_row_hash_2	A	NULL	NULL	NULL	YES	BTREE		
> +#add column with unique index on blob;
> +alter table t1 add column a blob unique;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  `a` blob DEFAULT NULL,
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	d	1	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_2	1	db_row_hash_2	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +#try to change the blob unique column name;
> +#this will change index to b tree;
> +alter table t1 modify  column a  int ,  modify column e int;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `d` text DEFAULT NULL,
> +  `e` int(11) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  `a` int(11) DEFAULT NULL,
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	d	1	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_2	1	db_row_hash_2	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
> +alter table t1 add column clm1 blob unique,add column clm2 blob unique;
> +#try changing the name; 
> +alter table t1 change column clm1 clm_changed1 blob, change column clm2 clm_changed2 blob;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `d` text DEFAULT NULL,
> +  `e` int(11) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  `a` int(11) DEFAULT NULL,
> +  `clm_changed1` blob DEFAULT NULL,
> +  `clm_changed2` blob DEFAULT NULL,
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
> +  UNIQUE KEY `a` (`a`),
> +  UNIQUE KEY `clm1` (`clm_changed1`),
> +  UNIQUE KEY `clm2` (`clm_changed2`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	d	1	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_2	1	db_row_hash_2	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	clm1	1	clm_changed1	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	clm2	1	clm_changed2	A	NULL	NULL	NULL	YES	HASH		
> +#now drop the unique key;
> +alter table t1 drop key clm1, drop key clm2;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `d` text DEFAULT NULL,
> +  `e` int(11) DEFAULT NULL,
> +  `f` int(11) DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  `a` int(11) DEFAULT NULL,
> +  `clm_changed1` blob DEFAULT NULL,
> +  `clm_changed2` blob DEFAULT NULL,
> +  UNIQUE KEY `d` (`d`(65535)),
> +  UNIQUE KEY `e` (`e`),
> +  UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
> +  UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	d	1	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_1	1	db_row_hash_1	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	db_row_hash_2	1	db_row_hash_2	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
> +drop table t1;
> +#now the table with key on multiple columns; the ultimate test;
> +create table t1(a blob, b int , c varchar(2000) , d text  , e varchar(3000) , f longblob , g int , h text ,
> +unique(a,b,c), unique(c,d,e),unique(e,f,g,h), unique(b,d,g,h));
> +insert into t1 values(1,1,1,1,1,1,1,1),(2,2,2,2,2,2,2,2),(3,3,3,3,3,3,3,3),(4,4,4,4,4,4,4,4),(5,5,5,5,5,5,5,5),
> +('maria',6,'maria','maria','maria','maria',6,'maria'),('mariadb',7,'mariadb','mariadb','mariadb','mariadb',8,'mariadb')
> +,(null,null,null,null,null,null,null,null),(null,null,null,null,null,null,null,null);
> +#table structure;
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	MUL	NULL	
> +b	int(11)	YES	MUL	NULL	
> +c	varchar(2000)	YES	MUL	NULL	
> +d	text	YES		NULL	
> +e	varchar(3000)	YES	MUL	NULL	
> +f	longblob	YES		NULL	
> +g	int(11)	YES		NULL	
> +h	text	YES		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`,`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`,`e`),
> +  UNIQUE KEY `e` (`e`,`f`,`g`,`h`),
> +  UNIQUE KEY `b` (`b`,`d`,`g`,`h`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	NULL	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	NULL	NULL	YES	HASH		
> +
> +MyISAM file:         DATADIR/test/t1
> +Record format:       Packed
> +Character set:       latin1_swedish_ci (8)
> +Data records:                    9  Deleted blocks:                 0
> +Recordlength:                 5092
> +
> +table description:
> +Key Start Len Index   Type
> +1   5081  8   multip. ulonglong NULL       
> +2   5073  8   multip. ulonglong NULL       
> +3   5065  8   multip. ulonglong NULL       
> +4   5057  8   multip. ulonglong NULL       
> +select * from information_schema.columns where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	COLUMN_DEFAULT	IS_NULLABLE	DATA_TYPE	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH	NUMERIC_PRECISION	NUMERIC_SCALE	DATETIME_PRECISION	CHARACTER_SET_NAME	COLLATION_NAME	COLUMN_TYPE	COLUMN_KEY	EXTRA	PRIVILEGES	COLUMN_COMMENT	IS_GENERATED	GENERATION_EXPRESSION
> +def	test	t1	a	1	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob	MUL		select,insert,update,references		NEVER	NULL
> +def	test	t1	b	2	NULL	YES	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11)	MUL		select,insert,update,references		NEVER	NULL
> +def	test	t1	c	3	NULL	YES	varchar	2000	2000	NULL	NULL	NULL	latin1	latin1_swedish_ci	varchar(2000)	MUL		select,insert,update,references		NEVER	NULL
> +def	test	t1	d	4	NULL	YES	text	65535	65535	NULL	NULL	NULL	latin1	latin1_swedish_ci	text			select,insert,update,references		NEVER	NULL
> +def	test	t1	e	5	NULL	YES	varchar	3000	3000	NULL	NULL	NULL	latin1	latin1_swedish_ci	varchar(3000)	MUL		select,insert,update,references		NEVER	NULL
> +def	test	t1	f	6	NULL	YES	longblob	4294967295	4294967295	NULL	NULL	NULL	NULL	NULL	longblob			select,insert,update,references		NEVER	NULL
> +def	test	t1	g	7	NULL	YES	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11)			select,insert,update,references		NEVER	NULL
> +def	test	t1	h	8	NULL	YES	text	65535	65535	NULL	NULL	NULL	latin1	latin1_swedish_ci	text			select,insert,update,references		NEVER	NULL
> +select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
> +TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	NON_UNIQUE	INDEX_SCHEMA	INDEX_NAME	SEQ_IN_INDEX	COLUMN_NAME	COLLATION	CARDINALITY	SUB_PART	PACKED	NULLABLE	INDEX_TYPE	COMMENT	INDEX_COMMENT
> +def	test	t1	0	test	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	c	2	d	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	c	3	e	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	e	1	e	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	e	2	f	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	e	3	g	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	e	4	h	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	b	1	b	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	b	2	d	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	b	3	g	A	0	NULL	NULL	YES	HASH		
> +def	test	t1	0	test	b	4	h	A	0	NULL	NULL	YES	HASH		
> +select * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
> +CONSTRAINT_CATALOG	CONSTRAINT_SCHEMA	CONSTRAINT_NAME	TABLE_CATALOG	TABLE_SCHEMA	TABLE_NAME	COLUMN_NAME	ORDINAL_POSITION	POSITION_IN_UNIQUE_CONSTRAINT	REFERENCED_TABLE_SCHEMA	REFERENCED_TABLE_NAME	REFERENCED_COLUMN_NAME
> +def	test	a	def	test	t1	a	1	NULL	NULL	NULL	NULL
> +def	test	a	def	test	t1	b	2	NULL	NULL	NULL	NULL
> +def	test	a	def	test	t1	c	3	NULL	NULL	NULL	NULL
> +def	test	c	def	test	t1	c	1	NULL	NULL	NULL	NULL
> +def	test	c	def	test	t1	d	2	NULL	NULL	NULL	NULL
> +def	test	c	def	test	t1	e	3	NULL	NULL	NULL	NULL
> +def	test	e	def	test	t1	e	1	NULL	NULL	NULL	NULL
> +def	test	e	def	test	t1	f	2	NULL	NULL	NULL	NULL
> +def	test	e	def	test	t1	g	3	NULL	NULL	NULL	NULL
> +def	test	e	def	test	t1	h	4	NULL	NULL	NULL	NULL
> +def	test	b	def	test	t1	b	1	NULL	NULL	NULL	NULL
> +def	test	b	def	test	t1	d	2	NULL	NULL	NULL	NULL
> +def	test	b	def	test	t1	g	3	NULL	NULL	NULL	NULL
> +def	test	b	def	test	t1	h	4	NULL	NULL	NULL	NULL
> +# table select we should not be able to see db_row_hash_1 column;
> +select * from t1 order by a;
> +a	b	c	d	e	f	g	h
> +NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
> +NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
> +1	1	1	1	1	1	1	1
> +2	2	2	2	2	2	2	2
> +3	3	3	3	3	3	3	3
> +4	4	4	4	4	4	4	4
> +5	5	5	5	5	5	5	5
> +maria	6	maria	maria	maria	maria	6	maria
> +mariadb	7	mariadb	mariadb	mariadb	mariadb	8	mariadb
> +select db_row_hash_1 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +select db_row_hash_2 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_2' in 'field list'
> +select db_row_hash_3 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_3' in 'field list'
> +#duplicate entry test;
> +#duplicate keys entry;
> +insert into t1 values(1,1,1,0,0,0,0,0);
> +ERROR 23000: Duplicate entry '1-1-1' for key 'a'
> +insert into t1 values(0,0,1,1,1,0,0,0);
> +ERROR 23000: Duplicate entry '1-1-1' for key 'c'
> +insert into t1 values(0,0,0,0,1,1,1,1);
> +ERROR 23000: Duplicate entry '1-1-1-1' for key 'e'
> +insert into t1 values(1,1,1,1,1,0,0,0);
> +ERROR 23000: Duplicate entry '1-1-1' for key 'a'
> +insert into t1 values(0,0,0,0,1,1,1,1);
> +ERROR 23000: Duplicate entry '1-1-1-1' for key 'e'
> +insert into t1 values(1,1,1,1,1,1,1,1);
> +ERROR 23000: Duplicate entry '1-1-1' for key 'a'
> +select db_row_hash_1,db_row_hash_2,db_row_hash_3,db_row_hash_4,db_row_hash_5 from t1;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
> +alter table t1 drop column db_row_hash_1, drop column db_row_hash_2, drop column db_row_hash_3;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 add column dg int , add column ef int , drop column db_row_hash_1;
> +ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
> +alter table t1 modify column db_row_hash_1 int , modify column db_row_hash_2 int, modify column db_row_hash_3 int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column ar int , add column rb int, modify column db_row_hash_1 int , modify column db_row_hash_3 int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 change column db_row_hash_1 dsds int , change column  db_row_hash_2  dfdf int , change column db_row_hash_3 gdfg int ;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +alter table t1 add column asd int, drop column a, change column db_row_hash_1 dsds int, change db_row_hash_3 fdfdfd int;
> +ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`,`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`,`e`),
> +  UNIQUE KEY `e` (`e`,`f`,`g`,`h`),
> +  UNIQUE KEY `b` (`b`,`d`,`g`,`h`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +# add column named db_row_hash_*;
> +alter table t1 add column db_row_hash_7 int , add column db_row_hash_5 int,
> +add column db_row_hash_1 int, add column db_row_hash_2 int;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  `db_row_hash_7` int(11) DEFAULT NULL,
> +  `db_row_hash_5` int(11) DEFAULT NULL,
> +  `db_row_hash_1` int(11) DEFAULT NULL,
> +  `db_row_hash_2` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535),`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`(65535),`e`),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `b` (`b`,`d`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +alter table t1 drop column db_row_hash_7  , drop column db_row_hash_5 ,
> +drop column db_row_hash_1, drop column db_row_hash_2 ;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` int(11) DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `d` text DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535),`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`(65535),`e`),
> +  UNIQUE KEY `b` (`b`,`d`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +#try to change column names;
> +alter table t1 change column a aa blob , change column b bb blob , change column d dd blob;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `aa` blob DEFAULT NULL,
> +  `bb` blob DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `dd` blob DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`aa`(65535),`bb`,`c`),
> +  UNIQUE KEY `c` (`c`,`dd`(65535),`e`),
> +  UNIQUE KEY `b` (`bb`,`dd`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	aa	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	bb	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	dd	A	0	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	1	bb	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	dd	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +alter table t1 change column aa a blob , change column bb b blob , change column dd d blob;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` blob DEFAULT NULL,
> +  `c` varchar(2000) DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535),`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`(65535),`e`),
> +  UNIQUE KEY `b` (`b`,`d`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +#now we will change the data type to int and varchar limit so that we no longer  require hash_index;
> +#on key a_b_c;
> +alter table t1 modify column a varchar(20) , modify column b varchar(20) , modify column c varchar(20);
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` varchar(20) DEFAULT NULL,
> +  `b` varchar(20) DEFAULT NULL,
> +  `c` varchar(20) DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`,`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`(65535),`e`),
> +  UNIQUE KEY `b` (`b`,`d`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	BTREE		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	NULL	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +#change it back;
> +alter table t1 modify column a blob , modify column b blob , modify column c blob;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` blob DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`,`b`,`c`),
> +  UNIQUE KEY `c` (`c`,`d`(65535),`e`),
> +  UNIQUE KEY `b` (`b`,`d`(65535),`g`,`h`(65535)),
> +  UNIQUE KEY `e` (`e`,`f`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	c	3	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	2	f	A	0	65535	NULL	YES	HASH		
> +t1	0	e	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	e	4	h	A	0	65535	NULL	YES	HASH		
> +#try to delete blob column in unique;
> +truncate table t1;
> +#now try to delete keys;
> +alter table t1 drop key c, drop key e;
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` blob DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  `e` varchar(3000) DEFAULT NULL,
> +  `f` longblob DEFAULT NULL,
> +  `g` int(11) DEFAULT NULL,
> +  `h` text DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535),`b`(65535),`c`(65535)),
> +  UNIQUE KEY `b` (`b`(65535),`d`(65535),`g`,`h`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	3	c	A	0	65535	NULL	YES	HASH		
> +t1	0	b	1	b	A	0	65535	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	b	3	g	A	0	NULL	NULL	YES	HASH		
> +t1	0	b	4	h	A	0	65535	NULL	YES	HASH		
> +drop table t1;
> +#now alter table containing some data basically some tests with ignore;
> +create table t1 (a blob);
> +insert into t1 values(1),(2),(3);
> +#normal alter table;
> +alter table t1 add unique key(a);
> +alter table t1 drop key a;
> +truncate table t1;
> +insert into t1 values(1),(1),(2),(2),(3);
> +alter table t1 add unique key(a);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +alter ignore table t1 add unique key(a);
> +select * from t1 order by a;
> +a
> +1
> +2
> +3
> +insert into t1 values(1);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +drop table t1;
> +#Now with multiple keys;
> +create table t1(a blob , b blob, c blob , d blob , e int);
> +insert into t1 values (1,1,1,1,1);
> +insert into t1 values (1,1,1,1,1);
> +insert into t1 values (2,1,1,1,1);
> +insert into t1 values (2,2,2,2,2);
> +insert into t1 values (3,3,4,4,4);
> +insert into t1 values (4,4,4,4,4);
> +alter table t1 add unique key(a,c), add unique key(b,d), add unique key(e);
> +ERROR 23000: Duplicate entry '1-1' for key 'a'
> +alter ignore  table t1 add unique key(a,c), add unique key(b,d), add unique key(e);
> +select * from t1 order by a;
> +a	b	c	d	e
> +1	1	1	1	1
> +2	2	2	2	2
> +3	3	4	4	4
> +insert into t1 values (1,12,1,13,14);
> +ERROR 23000: Duplicate entry '1-1' for key 'a'
> +insert into t1 values (12,1,14,1,14);
> +ERROR 23000: Duplicate entry '1-1' for key 'b'
> +insert into t1 values (13,12,13,14,4);
> +ERROR 23000: Duplicate entry '4' for key 'e'
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  `b` blob DEFAULT NULL,
> +  `c` blob DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  `e` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(65535),`c`(65535)),
> +  UNIQUE KEY `b` (`b`(65535),`d`(65535)),
> +  UNIQUE KEY `e` (`e`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	65535	NULL	YES	HASH		
> +t1	0	a	2	c	A	NULL	65535	NULL	YES	HASH		
> +t1	0	b	1	b	A	NULL	65535	NULL	YES	HASH		
> +t1	0	b	2	d	A	0	65535	NULL	YES	HASH		
> +t1	0	e	1	e	A	0	NULL	NULL	YES	BTREE		
> +drop table t1;
> +#visibility of db_row_hash 
> +create table t1 (a blob unique , b blob unique);
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +b	blob	YES	UNI	NULL	
> +insert into t1 values(1,19);
> +insert into t1 values(2,29);
> +insert into t1 values(3,39);
> +insert into t1 values(4,49);
> +create table t2 (DB_ROW_HASH_1 int, DB_ROW_HASH_2 int);
> +insert into t2 values(11,1);
> +insert into t2 values(22,2);
> +insert into t2 values(33,3);
> +insert into t2 values(44,4);
> +select * from t1 order by a;
> +a	b
> +1	19
> +2	29
> +3	39
> +4	49
> +select * from t2 order by DB_ROW_HASH_1;
> +DB_ROW_HASH_1	DB_ROW_HASH_2
> +11	1
> +22	2
> +33	3
> +44	4
> +select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1;
> +ERROR 42S22: Unknown column 'DB_ROW_HASH_1' in 'field list'
> +#bug
> +select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1,t2;
> +DB_ROW_HASH_1	DB_ROW_HASH_2
> +11	1
> +11	1
> +11	1
> +11	1
> +22	2
> +22	2
> +22	2
> +22	2
> +33	3
> +33	3
> +33	3
> +33	3
> +44	4
> +44	4
> +44	4
> +44	4
> +select * from t1 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t2);
> +ERROR 42S22: Unknown column 'DB_ROW_HASH_1' in 'IN/ALL/ANY subquery'
> +select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1,t2 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t2);
> +DB_ROW_HASH_1	DB_ROW_HASH_2
> +11	1
> +22	2
> +33	3
> +44	4
> +11	1
> +22	2
> +33	3
> +44	4
> +11	1
> +22	2
> +33	3
> +44	4
> +11	1
> +22	2
> +33	3
> +44	4
> +select * from t2 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t1);
> +DB_ROW_HASH_1	DB_ROW_HASH_2
> +11	1
> +22	2
> +33	3
> +44	4
> +select DB_ROW_HASH_1 from t1,t2 where t1.DB_ROW_HASH_1 = t2.DB_ROW_HASH_2;
> +ERROR 42S22: Unknown column 't1.DB_ROW_HASH_1' in 'where clause'
> +select DB_ROW_HASH_1 from t1 inner join t2 on t1.a = t2.DB_ROW_HASH_2;
> +DB_ROW_HASH_1
> +11
> +22
> +33
> +44
> +drop table t1,t2;
> +#very long blob entry;
> +SET @@GLOBAL.max_allowed_packet=67108864;
> +connect  'newcon', localhost, root,,;
> +connection newcon;
> +show variables like 'max_allowed_packet';
> +Variable_name	Value
> +max_allowed_packet	67108864
> +create table t1(a longblob unique, b longblob , c longblob , unique(b,c));
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	longblob	YES	UNI	NULL	
> +b	longblob	YES	MUL	NULL	
> +c	longblob	YES		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` longblob DEFAULT NULL,
> +  `b` longblob DEFAULT NULL,
> +  `c` longblob DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`),
> +  UNIQUE KEY `b` (`b`,`c`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	b	1	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	b	2	c	A	0	NULL	NULL	YES	HASH		
> +insert into t1 values(concat(repeat('sachin',10000000),'1'),concat(repeat('sachin',10000000),'1'),
> +concat(repeat('sachin',10000000),'1'));
> +insert into t1 values(concat(repeat('sachin',10000000),'2'),concat(repeat('sachin',10000000),'2'),
> +concat(repeat('sachin',10000000),'1'));
> +insert into t1 values(concat(repeat('sachin',10000000),'2'),concat(repeat('sachin',10000000),'2'),
> +concat(repeat('sachin',10000000),'4'));
> +ERROR 23000: Duplicate entry 'sachinsachinsachinsachinsachinsachinsachinsachinsachinsachinsach' for key 'a'
> +insert into t1 values(concat(repeat('sachin',10000000),'3'),concat(repeat('sachin',10000000),'1'),
> +concat(repeat('sachin',10000000),'1'));
> +ERROR 23000: Duplicate entry 'sachinsachinsachinsachinsachinsachinsachinsachinsachinsachinsach' for key 'b'
> +drop table t1;
> +#long key unique with different key length
> +create table t1(a blob, unique(a(3000)));
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	YES	UNI	NULL	
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	3000	NULL	YES	HASH		
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(3000))
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 value(concat(repeat('s',3000),'1'));
> +insert into t1 value(concat(repeat('s',3000),'2'));
> +ERROR 23000: Duplicate entry 'ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss' for key 'a'
> +insert into t1 value(concat(repeat('a',3000),'2'));
> +drop table t1;
> +create table t1(a varchar(4000), b longblob , c varchar(5000), d longblob, 
> +unique(a(3500), b), unique(c(4500), d));
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	varchar(4000)	YES	MUL	NULL	
> +b	longblob	YES		NULL	
> +c	varchar(5000)	YES	MUL	NULL	
> +d	longblob	YES		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` varchar(4000) DEFAULT NULL,
> +  `b` longblob DEFAULT NULL,
> +  `c` varchar(5000) DEFAULT NULL,
> +  `d` longblob DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`(3500),`b`),
> +  UNIQUE KEY `c` (`c`(4500),`d`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +show keys from t1;
> +Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
> +t1	0	a	1	a	A	NULL	3500	NULL	YES	HASH		
> +t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
> +t1	0	c	1	c	A	0	4500	NULL	YES	HASH		
> +t1	0	c	2	d	A	0	NULL	NULL	YES	HASH		
> +drop table t1;
> +disconnect newcon;
> +connection default;
> +SET @@GLOBAL.max_allowed_packet=4194304;
> +#ext bug
> +create table t1(a int primary key, b blob unique, c int, d blob , index(c));
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` int(11) NOT NULL,
> +  `b` blob DEFAULT NULL,
> +  `c` int(11) DEFAULT NULL,
> +  `d` blob DEFAULT NULL,
> +  PRIMARY KEY (`a`),
> +  UNIQUE KEY `b` (`b`),
> +  KEY `c` (`c`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 values(1,23,1,33);
> +insert into t1 values(2,23,1,33);
> +ERROR 23000: Duplicate entry '23' for key 'b'
> +drop table t1;
> +create table t2 (a blob unique , c int , index(c));
> +show create table t2;
> +Table	Create Table
> +t2	CREATE TABLE `t2` (
> +  `a` blob DEFAULT NULL,
> +  `c` int(11) DEFAULT NULL,
> +  UNIQUE KEY `a` (`a`),
> +  KEY `c` (`c`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t2 values(1,1);
> +insert into t2 values(2,1);
> +drop table t2;
> +#not null test //todo solve warnings
> +create table t1(a blob unique not null);
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	NO	UNI	NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob NOT NULL,
> +  UNIQUE KEY `a` (`a`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 values(1);
> +insert into t1 values(3);
> +insert into t1 values(1);
> +ERROR 23000: Duplicate entry '1' for key 'a'
> +drop table t1;
> +create table t1(a int primary key, b blob unique , c blob unique not null);
> +insert into t1 values(1,1,1);
> +insert into t1 values(2,1,2);
> +ERROR 23000: Duplicate entry '1' for key 'b'
> +insert into t1 values(3,3,1);
> +ERROR 23000: Duplicate entry '1' for key 'c'
> +drop table t1;
> +create table t1 (a blob unique not null, b blob not null, c blob not null, unique(b,c));
> +desc t1;
> +Field	Type	Null	Key	Default	Extra
> +a	blob	NO	UNI	NULL	
> +b	blob	NO	MUL	NULL	
> +c	blob	NO		NULL	
> +show create table t1;
> +Table	Create Table
> +t1	CREATE TABLE `t1` (
> +  `a` blob NOT NULL,
> +  `b` blob NOT NULL,
> +  `c` blob NOT NULL,
> +  UNIQUE KEY `a` (`a`),
> +  UNIQUE KEY `b` (`b`,`c`)
> +) ENGINE=MyISAM DEFAULT CHARSET=latin1
> +insert into t1 values (1, 2, 3);
> +insert into t1 values (2, 1, 3);
> +insert into t1 values (2, 1, 3);
> +ERROR 23000: Duplicate entry '2' for key 'a'
> +drop table t1;
> +#partition
> +create table t1(a blob unique) partition by hash(a);
> +ERROR HY000: A BLOB field is not allowed in partition function
> +#key length > 2^15 -1
> +create table t1(a blob, unique(a(100001)));
> +ERROR 42000: Specified key was too long; max key length is 1000 bytes
> +set @@GLOBAL.max_allowed_packet= @allowed_packet;
> diff --git a/mysql-test/main/long_unique_debug.result b/mysql-test/main/long_unique_debug.result
> new file mode 100644
> --- /dev/null
> +++ b/mysql-test/main/long_unique_debug.result
> @@ -0,0 +1,32 @@
> +#In this test case we will check what will happen in the case of hash collusion

collision, not collusion :)

> +SET debug_dbug="d,same_long_unique_hash";
> +create table t1(a blob unique);
> +insert into t1 values('xyz');
> +insert into t1 values('abc');
> +insert into t1 values('sachin');
> +insert into t1 values('sachin');
> +ERROR 23000: Duplicate entry 'sachin' for key 'a'
> +insert into t1 values('maria');
> +insert into t1 values('maria');
> +ERROR 23000: Duplicate entry 'maria' for key 'a'
> +drop table t1;
> +create table t1(a blob unique, b blob unique);
> +insert into t1 values('xyz', 11);
> +insert into t1 values('abc', 22);
> +insert into t1 values('sachin', 1);
> +insert into t1 values('sachin', 4);
> +ERROR 23000: Duplicate entry 'sachin' for key 'a'
> +insert into t1 values('maria', 2);
> +insert into t1 values('maria', 3);
> +ERROR 23000: Duplicate entry 'maria' for key 'a'
> +drop table t1;
> +create table t1(a blob , b blob , unique(a,b));
> +insert into t1 values('xyz', 11);
> +insert into t1 values('abc', 22);
> +insert into t1 values('sachin', 1);
> +insert into t1 values('sachin', 1);
> +ERROR 23000: Duplicate entry 'sachin-1' for key 'a'
> +insert into t1 values('maria', 2);
> +insert into t1 values('maria', 2);
> +ERROR 23000: Duplicate entry 'maria-2' for key 'a'
> +drop table t1;
> diff --git a/mysql-test/main/mdev-504.test b/mysql-test/main/mdev-504.test
> --- a/mysql-test/main/mdev-504.test
> +++ b/mysql-test/main/mdev-504.test
> @@ -44,7 +43,7 @@ while ($trial)
>    --connect (con2,localhost,root,,)
>    --send CALL p_analyze()
>  
> -  --let $run = 100
> +  --let $run = 1

Why?

>  
>    while ($run)
>    {
> diff --git a/mysql-test/main/type_blob.result b/mysql-test/main/type_blob.result
> --- a/mysql-test/main/type_blob.result
> +++ b/mysql-test/main/type_blob.result
> @@ -370,7 +370,7 @@ a	1
>  hello	1
>  drop table t1;
>  create table t1 (a text, unique (a(2100)));
> -ERROR 42000: Specified key was too long; max key length is 1000 bytes
> +drop table t1;

or remove the create table instead, it's not a useful test anymore

>  create table t1 (a text, key (a(2100)));
>  Warnings:
>  Note	1071	Specified key was too long; max key length is 1000 bytes
> diff --git a/sql/field.h b/sql/field.h
> --- a/sql/field.h
> +++ b/sql/field.h
> @@ -687,7 +687,7 @@ class Field: public Value_source
>      GEOM_MULTIPOINT = 4, GEOM_MULTILINESTRING = 5, GEOM_MULTIPOLYGON = 6,
>      GEOM_GEOMETRYCOLLECTION = 7
>    };
> -  enum imagetype { itRAW, itMBR};
> +  enum imagetype { itRAW, itMBR, itHASH};

unused

>  
>    utype		unireg_check;
>    uint32	field_length;		// Length of field
> diff --git a/sql/handler.cc b/sql/handler.cc
> --- a/sql/handler.cc
> +++ b/sql/handler.cc
> @@ -3686,9 +3686,19 @@ void handler::print_error(int error, myf errflag)
>        uint key_nr=get_dup_key(error);
>        if ((int) key_nr >= 0 && key_nr < table->s->keys)
>        {
> +        KEY *long_key= NULL;
> +        if (table->key_info[key_nr].algorithm
> +                == HA_KEY_ALG_LONG_HASH)
> +        {
> +          long_key= table->key_info + key_nr;
> +            setup_keyinfo_hash(long_key);
> +        }
>          print_keydup_error(table, &table->key_info[key_nr], errflag);
> +        if (long_key)
> +          re_setup_keyinfo_hash(long_key);



>          DBUG_VOID_RETURN;
>        }
> +      table->re_setup_table();
>      }
>      textno=ER_DUP_KEY;
>      break;
> @@ -6256,6 +6268,162 @@ int handler::ha_reset()
>    DBUG_RETURN(reset());
>  }
>  
> +static int check_duplicate_long_entry_key(TABLE *table, handler *h, uchar *new_rec,
> +                                   uint key_no)
> +{
> +  Field *hash_field;
> +  int result, error= 0;
> +  KEY *key_info= table->key_info + key_no;
> +  hash_field= key_info->key_part->field;
> +  DBUG_ASSERT((table->key_info[key_no].flags & HA_NULL_PART_KEY &&
> +      table->key_info[key_no].key_length == HA_HASH_KEY_LENGTH_WITH_NULL)
> +    || table->key_info[key_no].key_length == HA_HASH_KEY_LENGTH_WITHOUT_NULL);
> +  uchar ptr[HA_HASH_KEY_LENGTH_WITH_NULL];
> +
> +  if (hash_field->is_real_null())
> +    return 0;
> +

remember, you have `key_info= table->key_info + key_no` above :)
you don't need to write `table->key_info[key_no]` anymore here

> +  key_copy(ptr, new_rec, &table->key_info[key_no],
> +              table->key_info[key_no].key_length, false);
> +
> +  if (!table->check_unique_buf)
> +    table->check_unique_buf= (uchar *)alloc_root(&table->mem_root,
> +                                    table->s->reclength*sizeof(uchar));

C99 standard says

  6.5.3.4 The sizeof operator

     When applied to an operand that has type char, unsigned
     char, or signed char, (or a qualified version thereof) the
     result is 1.

so don't bother with `*sizeof(uchar)`

> +
> +  result= h->ha_index_init(key_no, 0);
> +  if (result)
> +    return result;
> +  result= h->ha_index_read_map(table->check_unique_buf,
> +                               ptr, HA_WHOLE_KEY, HA_READ_KEY_EXACT);
> +  if (!result)
> +  {
> +    bool is_same;
> +    Field * t_field;
> +    Item_func_hash * temp= (Item_func_hash *)hash_field->vcol_info->expr;
> +    Item ** arguments= temp->arguments();
> +    uint arg_count= temp->argument_count();
> +    do
> +    {
> +      long diff= table->check_unique_buf - new_rec;
> +      is_same= true;
> +      for (uint j=0; j < arg_count; j++)

you can add `is_same && ` here to the for() condition too.

> +      {
> +        DBUG_ASSERT(arguments[j]->type() == Item::FIELD_ITEM ||
> +                    // this one for left(fld_name,length)
> +                    arguments[j]->type() == Item::FUNC_ITEM);
> +        if (arguments[j]->type() == Item::FIELD_ITEM)
> +        {
> +          t_field= static_cast<Item_field *>(arguments[j])->field;
> +          if (t_field->cmp_offset(diff))
> +            is_same= false;
> +        }
> +        else
> +        {
> +          Item_func_left *fnc= static_cast<Item_func_left *>(arguments[j]);
> +          DBUG_ASSERT(!my_strcasecmp(system_charset_info, "left", fnc->func_name()));
> +          DBUG_ASSERT(fnc->arguments()[0]->type() == Item::FIELD_ITEM);
> +          t_field= static_cast<Item_field *>(fnc->arguments()[0])->field;
> +          uint length= fnc->arguments()[1]->val_int();
> +          if (t_field->cmp_max(t_field->ptr, t_field->ptr + diff, length))
> +            is_same= false;
> +        }
> +      }
> +    }
> +    while (!is_same && !(result= table->file->ha_index_next_same(table->check_unique_buf,
> +                         ptr, table->key_info[key_no].key_length)));
> +    if (is_same)
> +    {
> +      table->dupp_hash_key= key_no;
> +      error= HA_ERR_FOUND_DUPP_KEY;
> +      goto exit;
> +    }
> +    else
> +      goto exit;
> +  }
> +  if (result == HA_ERR_LOCK_WAIT_TIMEOUT)
> +  {
> +    table->dupp_hash_key= key_no;
> +    //TODO check if this is the only case
> +    error= HA_ERR_FOUND_DUPP_KEY;

why not to keep HA_ERR_LOCK_WAIT_TIMEOUT?

> +  }
> +  exit:
> +  h->ha_index_end();
> +  return error;
> +}

empty line between functions, please

> +/** @brief
> +    check whether inserted records breaks the
> +    unique constraint on long columns.
> +    @returns 0 if no duplicate else returns error
> +  */
> +static int check_duplicate_long_entries(TABLE *table, handler *h, uchar *new_rec)
> +{
> +  table->dupp_hash_key= -1;
> +  int result;
> +  for (uint i= 0; i < table->s->keys; i++)
> +  {
> +    if (table->key_info[i].algorithm == HA_KEY_ALG_LONG_HASH &&
> +            (result= check_duplicate_long_entry_key(table, h, new_rec, i)))
> +      return result;
> +  }
> +  return 0;
> +}
> +
> +/** @brief
> +    check whether updated records breaks the
> +    unique constraint on long columns.
> +    In the case of update we just need to check the specic key
> +    reason for that is consider case
> +    create table t1(a blob , b blob , x blob , y blob ,unique(a,b)
> +                                                    ,unique(x,y))
> +    and update statement like this
> +    update t1 set a=23+a; in this case if we try to scan for
> +    whole keys in table then index scan on x_y will return 0
> +    because data is same so in the case of update we take
> +    key as a parameter in normal insert key should be -1
> +    @returns 0 if no duplicate else returns error
> +  */
> +static int check_duplicate_long_entries_update(TABLE *table, handler *h, uchar *new_rec)
> +{
> +  Field *field;
> +  uint key_parts;
> +  int error= 0;
> +  KEY *keyinfo;
> +  KEY_PART_INFO *keypart;
> +  /*
> +     Here we are comparing whether new record and old record are same
> +     with respect to fields in hash_str
> +   */
> +  long reclength= table->record[1]-table->record[0];
> +  if (!table->update_handler)
> +    table->clone_handler_for_update();
> +  for (uint i= 0; i < table->s->keys; i++)
> +  {
> +    keyinfo= table->key_info + i;
> +    if (keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)
> +    {
> +      key_parts= fields_in_hash_keyinfo(keyinfo);
> +      keypart= keyinfo->key_part - key_parts;
> +      for (uint j= 0; j < key_parts; j++, keypart++)
> +      {
> +        field= keypart->field;
> +        /* Compare fields if they are different then check for duplicates*/
> +        if(field->cmp_binary_offset(reclength))
> +        {
> +          if((error= check_duplicate_long_entry_key(table, table->update_handler,
> +                                                 new_rec, i)))
> +            goto exit;
> +          /*
> +            break beacuse check_duplicate_long_entrie_key will
> +            take care of remaning fields

three typos in two lines :)

> +           */
> +          break;
> +        }
> +      }
> +    }
> +  }
> +  exit:
> +  return error;
> +}
>  
>  int handler::ha_write_row(uchar *buf)
>  {
> diff --git a/sql/item.cc b/sql/item.cc
> --- a/sql/item.cc
> +++ b/sql/item.cc
> @@ -356,7 +356,7 @@ Item::Item(THD *thd):
>     /* Initially this item is not attached to any JOIN_TAB. */
>    join_tab_idx= MAX_TABLES;
>  
> -  /* Put item in free list so that we can free all items at end */
> +  /* Put item in free list so that we can free all items at end only if*/

Huh?

>    next= thd->free_list;
>    thd->free_list= this;
>    /*
> diff --git a/sql/item_func.cc b/sql/item_func.cc
> --- a/sql/item_func.cc
> +++ b/sql/item_func.cc
> @@ -1718,6 +1718,48 @@ bool Item_func_mod::fix_length_and_dec()
>    DBUG_RETURN(FALSE);
>  }
>  
> +inline void calc_hash_for_unique(ulong &nr1, ulong &nr2, String *str)

static inline (or simply static, a compiler will inline it anyway)

> +{
> +  CHARSET_INFO *cs;
> +  uchar l[4];
> +  int4store(l, str->length());
> +  cs= str->charset();
> +  cs->coll->hash_sort(cs, l, sizeof(l), &nr1, &nr2);
> +  cs= str->charset();
> +  cs->coll->hash_sort(cs, (uchar *)str->ptr(), str->length(), &nr1, &nr2);
> +}
> +
> +longlong  Item_func_hash::val_int()
> +{
> +  DBUG_EXECUTE_IF("same_long_unique_hash", return 9;);

good that you've added tests for collisions!

> +  unsigned_flag= true;
> +  ulong nr1= 1,nr2= 4;
> +  CHARSET_INFO *cs;
> +  String * str;
> +  for(uint i= 0;i<arg_count;i++)
> +  {
> +    str = args[i]->val_str();
> +    if(args[i]->null_value)
> +    {
> +      null_value= 1;
> +      return 0;
> +    }
> +   calc_hash_for_unique(nr1, nr2, str);
> +  }
> +  null_value= 0;
> +  return   (longlong)nr1;
> +}
> +
> +
> +bool Item_func_hash::fix_length_and_dec()
> +{
> +  maybe_null= 1;

Why are you forcing maybe_null=1?

Most functions are "normal" - they can return NULL if one of the
arguments is NULL, otherwise they don't return NULL.
And Item_func::fix_fields() sets maybe_null accordingly, it'll
be 1 if any of the arguments has maybe_null==1, otherwise
maybe_null will be 0.

You only need to set maybe_null explicitly if your function is
special, for ISNULL(x) # never returns NULL, and NULLIF(x,y)
can return NULL when both arguments are not NULL.

Looks like in your case the default maybe_null beahavior is
correct, though.

> +  decimals= 0;
> +  max_length= 8;
> +  return false;
> +}
> +
> +
>  
>  double Item_func_neg::real_op()
>  {
> diff --git a/sql/sql_base.cc b/sql/sql_base.cc
> --- a/sql/sql_base.cc
> +++ b/sql/sql_base.cc
> @@ -994,6 +994,8 @@ void close_thread_table(THD *thd, TABLE **table_ptr)
>      table->file->update_global_table_stats();
>      table->file->update_global_index_stats();
>    }
> +  if (table->update_handler)
> +    table->delete_update_handler();

you're doing it in sql_update.cc, isn't it enough?

>  
>    /*
>      This look is needed to allow THD::notify_shared_lock() to
> diff --git a/sql/sql_show.cc b/sql/sql_show.cc
> --- a/sql/sql_show.cc
> +++ b/sql/sql_show.cc
> @@ -2306,7 +2307,7 @@ int show_create_table(THD *thd, TABLE_LIST *table_list, String *packet,
>        */
>        packet->append(STRING_WITH_LEN("PRIMARY KEY"));
>      }
> -    else if (key_info->flags & HA_NOSAME)
> +    else if (key_info->flags & HA_NOSAME || key_info->algorithm == HA_KEY_ALG_LONG_HASH)

I'd think that after setup_table_hash(), HA_NOSAME should be set
and you wouldn't need extra checks.

>        packet->append(STRING_WITH_LEN("UNIQUE KEY "));
>      else if (key_info->flags & HA_FULLTEXT)
>        packet->append(STRING_WITH_LEN("FULLTEXT KEY "));
> @@ -6546,7 +6548,7 @@ static int get_schema_stat_record(THD *thd, TABLE_LIST *tables,
>    else if (!tables->view)
>    {
>      TABLE *show_table= tables->table;
> -    KEY *key_info=show_table->s->key_info;
> +    KEY *key_info=show_table->key_info;

you mean, TABLE_SHARE::key_info shows your HASH definition?
and but you change (with setup_table_hash) TABLE::key_info
to store the original user's UNIQUE definition?

Why is TABLE_SHARE::key_info changed?

>      if (show_table->file)
>      {
>        show_table->file->info(HA_STATUS_VARIABLE |
> diff --git a/sql/sql_table.cc b/sql/sql_table.cc
> --- a/sql/sql_table.cc
> +++ b/sql/sql_table.cc
> @@ -4106,12 +4177,28 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
>      if (key->type == Key::UNIQUE && !(key_info->flags & HA_NULL_PART_KEY))
>        unique_key=1;
>      key_info->key_length=(uint16) key_length;
> -    if (key_length > max_key_length && key->type != Key::FULLTEXT)
> +    if (key_length > max_key_length && key->type != Key::FULLTEXT &&
> +            !is_hash_field_needed)
>      {
>        my_error(ER_TOO_LONG_KEY,MYF(0),max_key_length);
>        DBUG_RETURN(TRUE);
>      }
>  
> +    if (is_hash_field_needed)
> +    {
> +      Create_field *hash_fld= add_hash_field(thd, &alter_info->create_list,
> +                       create_info->default_table_charset,
> +                       key_info);
> +      hash_fld->offset= record_offset;
> +      record_offset+= hash_fld->pack_length;
> +      if (key_info->flags & HA_NULL_PART_KEY)
> +         null_fields++;
> +      else
> +      {
> +        hash_fld->flags|= NOT_NULL_FLAG;
> +        hash_fld->pack_flag&= ~FIELDFLAG_MAYBE_NULL;
> +      }
> +    }

Hmm, haven't we agreed *not* to write the virtual hash field
into the frm, not show it to create/alter table and
add it automatically when the table is opened?

>      if (validate_comment_length(thd, &key->key_create_info.comment,
>                                  INDEX_COMMENT_MAXLEN,
>                                  ER_TOO_LONG_INDEX_COMMENT,
> diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
> --- a/sql/sql_yacc.yy
> +++ b/sql/sql_yacc.yy
> @@ -10820,6 +10820,12 @@ function_call_conflict:
>              if (unlikely($$ == NULL))
>                MYSQL_YYABORT;
>            }
> +        | HASH_SYM '(' expr_list ')'
> +          {
> +            $$= new (thd->mem_root)Item_func_hash(thd,*$3);
> +            if (unlikely($$ == NULL))
> +              MYSQL_YYABORT;
> +          }

Haven't we agreed to make this HASH() function fully internal,
not visible to the parser?

>            /* LAST_VALUE here conflicts with the definition for window functions.
>               We have these 2 separate rules to remove the shift/reduce conflict.
>            */
> diff --git a/sql/table.cc b/sql/table.cc
> --- a/sql/table.cc
> +++ b/sql/table.cc
> @@ -747,7 +746,7 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end,
>      if (i == 0)
>      {
>        ext_key_parts+= (share->use_ext_keys ? first_keyinfo->user_defined_key_parts*(keys-1) : 0); 
> -      n_length=keys * sizeof(KEY) + ext_key_parts * sizeof(KEY_PART_INFO);
> +      n_length=keys * sizeof(KEY) + (ext_key_parts) * sizeof(KEY_PART_INFO);

Another left-over from an intermediate implementation? :)

>        if (!(keyinfo= (KEY*) alloc_root(&share->mem_root,
>  				       n_length + len)))
>          return 1;
> @@ -798,6 +797,12 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end,
>        }
>        key_part->store_length=key_part->length;
>      }
> +    if (keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)
> +    {
> +      keyinfo->key_length= HA_HASH_KEY_LENGTH_WITHOUT_NULL;
> +      //Storing key hash
> +      key_part++;
> +    }

I don't understand what you do here

>  
>      /*
>        Add primary key to end of extended keys for non unique keys for
> @@ -831,7 +836,9 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end,
>        if (j == first_key_parts)
>          keyinfo->ext_key_flags= keyinfo->flags | HA_EXT_NOSAME;
>      }
> -    share->ext_key_parts+= keyinfo->ext_key_parts;  
> +    if (keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)
> +      share->ext_key_parts++;
> +    share->ext_key_parts+= keyinfo->ext_key_parts;

I don't understand what you do here

>    }
>    keynames=(char*) key_part;
>    strpos+= strnmov(keynames, (char *) strpos, frm_image_end - strpos) - keynames;
> @@ -3322,6 +3421,36 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
>  
>        key_part_end= key_part + (share->use_ext_keys ? key_info->ext_key_parts :
>  			                              key_info->user_defined_key_parts) ;
> +      if (key_info->algorithm == HA_KEY_ALG_LONG_HASH)
> +      {
> +        /*
> +         Either it can be first time opening the table share  or it can be second time
> +         of more. The difference is when it is first time key_part[0]->fieldnr points
> +         to blob/long field, but when it is 2nd time there will bw always one key_part
> +         and it will point to hash_field.
> +         So in the case of 2nd time we will make key_info->key_part point to start of long
> +         field.

you're overcomplicating here.

if you would *always* create your HASH key_def in
parse_vcol_defs(), you'll have TABLE_SHARE to be always "like
the first time", you simply never modify TABLE_SHARE and always
modify TABLEin parse_vcol_defs().

and you won't need setup_keyinfo_hash/setup_table_hash functions
either.

> +         For example we have unique(a,b,c)
> +           In first share opening key_part will point to a field
> +            but in parse_vcol_defs it will be changed to point to db_row_hash field
> +           in Second or later opening key_part will be pointing to db_row_hash
> +         We will chnage it back to point to field a, because in this way we can create
> +         vcol_info for hash field in parse_vcol_defs.
> +         */
> +        //Second or more time share opening
> +        key_info->user_defined_key_parts= 0;
> +        key_part_end= key_part;
> +        while(!(share->field[key_part_end->fieldnr -1 ]->flags & LONG_UNIQUE_HASH_FIELD))
> +        {
> +          key_part_end++;
> +          key_info->user_defined_key_parts++;
> +        }
> +        key_info->usable_key_parts= key_info->ext_key_parts= key_info->user_defined_key_parts;
> +        key_part_end++;
> +        share_keyinfo= share->key_info + key_no;
> +        if (share_keyinfo->key_part->field->flags & LONG_UNIQUE_HASH_FIELD)
> +          share_keyinfo->key_part-= key_info->user_defined_key_parts;
> +      }
>        for ( ; key_part < key_part_end; key_part++)
>        {
>          Field *field= key_part->field= outparam->field[key_part->fieldnr - 1];
> @@ -8498,6 +8630,120 @@ double KEY::actual_rec_per_key(uint i)
>  }
>  
>  
> +/*
> +   find out the field positoin in hash_str()
> +   position starts from 0
> +   else return -1;
> +*/
> +int find_field_pos_in_hash(Item *hash_item, const  char * field_name)
> +{
> +  Item_func_or_sum * temp= static_cast<Item_func_or_sum *>(hash_item);
> +  Item_args * t_item= static_cast<Item_args *>(temp);
> +  uint arg_count= t_item->argument_count();
> +  Item ** arguments= t_item->arguments();
> +  Field * t_field;
> +
> +  for (uint j=0; j < arg_count; j++)
> +  {
> +    DBUG_ASSERT(arguments[j]->type() == Item::FIELD_ITEM ||
> +                arguments[j]->type() == Item::FUNC_ITEM);
> +    if (arguments[j]->type() == Item::FIELD_ITEM)
> +    {
> +      t_field= static_cast<Item_field *>(arguments[j])->field;
> +    }
> +    else
> +    {
> +      Item_func_left *fnc= static_cast<Item_func_left *>(arguments[j]);
> +      t_field= static_cast<Item_field *>(fnc->arguments()[0])->field;
> +    }
> +    if (!my_strcasecmp(system_charset_info, t_field->field_name.str, field_name))
> +      return j;
> +  }
> +  return -1;
> +}
> +
> +/*
> +   find total number of field in hash expr
> +*/
> +int fields_in_hash_keyinfo(KEY *keyinfo)
> +{
> +  Item_func_hash * temp= (Item_func_hash *)
> +                     keyinfo->key_part->field->vcol_info->expr;
> +  return temp->argument_count();
> +}
> +
> +void setup_keyinfo_hash(KEY *key_info)
> +{
> +  uint no_of_keyparts= fields_in_hash_keyinfo(key_info);
> +  key_info->key_part-= no_of_keyparts;
> +  key_info->user_defined_key_parts= key_info->usable_key_parts=
> +               key_info->ext_key_parts= no_of_keyparts;

add DBUG_ASSERT to make sure it's your HA_KEY_ALG_LONG_HASH

> +}
> +
> +void re_setup_keyinfo_hash(KEY *key_info)
> +{
> +  while(!(key_info->key_part->field->flags & LONG_UNIQUE_HASH_FIELD))
> +    key_info->key_part++;
> +  key_info->user_defined_key_parts= key_info->usable_key_parts=
> +               key_info->ext_key_parts= 1;
> +}
> +/**
> +  @brief clone of current handler.
> +  Creates a clone of handler used in update for
> +  unique hash key.
> +*/
> +void TABLE::clone_handler_for_update()
> +{
> +  handler *update_handler= NULL;
> +  if (!s->long_unique_table)
> +    return;
> +  update_handler= file->clone(s->normalized_path.str,
> +                                     in_use->mem_root);
> +  update_handler->ha_external_lock(in_use, F_RDLCK);
> +  this->update_handler= update_handler;
> +  return;
> +}
> +
> +/**
> + @brief Deletes update handler object
> +*/
> +void TABLE::delete_update_handler()
> +{
> +  update_handler->ha_external_lock(in_use, F_UNLCK);
> +  update_handler->ha_close();
> +  delete update_handler;
> +  this->update_handler= NULL;
> +}
> +/**
> + @brief This function makes table object with
> +        long unique keys ready for optimizer and alter table

Looks like a bad function name and a bad explanation.
I think - but not sure! - that it restores the original
UNIQUE definition, with columns as specified by the user.
Is that so?

> + @param table Table object
> + */
> +void TABLE::setup_table_hash()
> +{
> +
> +  if (!this->s->long_unique_table)
> +    return;
> +  KEY *keyinfo= key_info;
> +  for (uint i= 0; i < this->s->keys; i++, keyinfo++)
> +    if (keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)
> +      setup_keyinfo_hash(keyinfo);
> +}
> +
> +/**
> + @brief Revert the effect of setup_table_hash
> + @param table Table Object
> + */
> +void TABLE::re_setup_table()
> +{
> +  if (!s->long_unique_table)
> +    return;
> +  KEY *keyinfo= key_info;
> +  for (uint i= 0; i < s->keys; i++, keyinfo++)
> +    if (keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)
> +      re_setup_keyinfo_hash(keyinfo);
> +}
> +
>  LEX_CSTRING *fk_option_name(enum_fk_option opt)
>  {
>    static LEX_CSTRING names[]=
> diff --git a/sql/table.h b/sql/table.h
> --- a/sql/table.h
> +++ b/sql/table.h
> @@ -1105,6 +1120,17 @@ struct TABLE
>    THD	*in_use;                        /* Which thread uses this */
>  
>    uchar *record[3];			/* Pointer to records */
> +  /* record buf to resolve hash collisions for long UNIQUE constraints */
> +  uchar *check_unique_buf;
> +  handler *update_handler;  /* Handler used in case of update */
> +  /*
> +     In the case of write row for long unique we are unable to find
> +     which key is violated. Because we in case of duplicate hash we never reach
> +     handler write_row function. So print_error will always print that
> +     key 0 is violated. We store which key is violated in this variable
> +     by default this should be initialized to -1
> +   */
> +  int dupp_hash_key;

couldn't you simply store it in table->file->errkey ?

>    uchar *write_row_record;		/* Used as optimisation in
>  					   THD::write_row */
>    uchar *insert_values;                  /* used by INSERT ... UPDATE */
> diff --git a/sql/table_cache.cc b/sql/table_cache.cc
> --- a/sql/table_cache.cc
> +++ b/sql/table_cache.cc
> @@ -822,13 +822,10 @@ TABLE_SHARE *tdc_acquire_share(THD *thd, TABLE_LIST *tl, uint flags,
>  
>      if (res == -1)
>        DBUG_RETURN(0);
> -    else if (res == 1)
> -      continue;

Why?

>  
>      element= (TDC_element*) lf_hash_search_using_hash_value(&tdc_hash,
>               thd->tdc_hash_pins, hash_value, (uchar*) key, key_length);
>      lf_hash_search_unpin(thd->tdc_hash_pins);
> -    DBUG_ASSERT(element);
>  
>      if (!(share= alloc_table_share(tl->db.str, tl->table_name.str, key, key_length)))
>      {
> diff --git a/storage/myisam/myisamchk.c b/storage/myisam/myisamchk.c
> --- a/storage/myisam/myisamchk.c
> +++ b/storage/myisam/myisamchk.c
> @@ -1333,7 +1333,8 @@ static void descript(HA_CHECK *param, register MI_INFO *info, char * name)
>         key++,keyinfo++)
>    {
>      keyseg=keyinfo->seg;
> -    if (keyinfo->flag & HA_NOSAME) text="unique ";
> +    if (keyinfo->flag & HA_NOSAME)
> +        text="unique ";

I presume you can revert this change, looks like some left-over
from when you tried to make myisamchk to recognize your uniques
and then later reverted it.

>      else if (keyinfo->flag & HA_FULLTEXT) text="fulltext ";
>      else text="multip.";
>  
> 

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx


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