The number of pagecache segments affects counting of used/unused blocks

--source include/have_sequence.inc

create table t1 (pk int primary key, a int, b int, key(a)) engine=Aria;

insert into t1 select seq, seq, seq from seq_1_to_50000;

create table t2 (pk int primary key, a int, b int, key(a)) engine=Aria;

insert into t2 select seq, seq, seq from seq_1_to_50000;

--let $segment_values=1,2,4,16

--let $count= 4

--let $n= 0

while ($n < $count)

{

    --inc $n

    --let $sgm=`select ELT($n, $segment_values)`

    --let $restart_parameters= --aria-pagecache-buffer-size=32M --aria-pagecache-segments=$sgm

    --source include/restart_mysqld.inc

    --echo #

    --echo # With $sgm segment(s):

    --echo #

    --disable_result_log

    select * from t1;

    select * from t2;

    --enable_result_log

    select variable_name, variable_value from information_schema.global_status where variable_name in ('Aria_pagecache_blocks_unused','Aria_pagecache_blocks_used');

}

drop table t1, t2;

#

# With 1 segment(s):

#

select * from t1;

select * from t2;

select variable_name, variable_value from information_schema.global_status where variable_name in ('Aria_pagecache_blocks_unused','Aria_pagecache_blocks_used');

variable_name	variable_value

ARIA_PAGECACHE_BLOCKS_UNUSED	3353

ARIA_PAGECACHE_BLOCKS_USED	543

# restart: --aria-pagecache-buffer-size=32M --aria-pagecache-segments=2

#

# With 2 segment(s):

#

select * from t1;

select * from t2;

select variable_name, variable_value from information_schema.global_status where variable_name in ('Aria_pagecache_blocks_unused','Aria_pagecache_blocks_used');

variable_name	variable_value

ARIA_PAGECACHE_BLOCKS_UNUSED	3351

ARIA_PAGECACHE_BLOCKS_USED	545

# restart: --aria-pagecache-buffer-size=32M --aria-pagecache-segments=4

#

# With 4 segment(s):

#

select * from t1;

select * from t2;

select variable_name, variable_value from information_schema.global_status where variable_name in ('Aria_pagecache_blocks_unused','Aria_pagecache_blocks_used');

variable_name	variable_value

ARIA_PAGECACHE_BLOCKS_UNUSED	3349

ARIA_PAGECACHE_BLOCKS_USED	545

# restart: --aria-pagecache-buffer-size=32M --aria-pagecache-segments=16

#

# With 16 segment(s):

#

select * from t1;

select * from t2;

select variable_name, variable_value from information_schema.global_status where variable_name in ('Aria_pagecache_blocks_unused','Aria_pagecache_blocks_used');

variable_name	variable_value

ARIA_PAGECACHE_BLOCKS_UNUSED	3378

ARIA_PAGECACHE_BLOCKS_USED	497