create table t1 (
a varchar(255),
b varchar(255),
c varchar(255),
d varchar(255),
primary key(a,b,c,d)
) engine=innodb character set latin1;
SET unique_checks=0, foreign_key_checks= 0;
begin;
insert into t1 select
repeat(uuid(), 7), 
repeat(uuid(), 7), 
repeat(uuid(), 7), 
repeat(uuid(), 7)
from seq_1_to_16384;
insert into t1 values ('z','z','z','z');
commit;
# Restart the server to make sure we have an empty InnoDB Buffer Pool 
# (in the test's .opt file we've disabled buffer pool saving/loading 
#  and also tried to disable any background activity)
SET GLOBAL innodb_fast_shutdown=0;
# restart
set @innodb_pages_read0= 
(select variable_value 
from information_schema.session_status 
where variable_name like 'innodb_pages_read');
set @js='$analyze_output';
set @js=json_extract(@js, '$.query_block.nested_loop[0].table.r_engine_stats');
set @pages_accessed= cast(json_value(@js,'$.pages_accessed') as INT);
set @pages_read_count= cast(json_value(@js,'$.pages_read_count') as INT);
set @pages_prefetch_read_count= cast(json_value(@js,'$.pages_prefetch_read_count') as INT);
select @pages_accessed > 1000 and @pages_accessed < 1500;
@pages_accessed > 1000 and @pages_accessed < 1500
1
set @total_read = (@pages_read_count + @pages_prefetch_read_count);
set @low_ok= @pages_accessed*0.75 < @total_read;
set @high_ok= @total_read < @pages_accessed*1.50;
select @low_ok, @high_ok;
@low_ok	@high_ok
1	1
select
if(@low_ok and @high_ok,0,@pages_accessed) unexpected_accessed,
if(@low_ok and @high_ok,0,@total_read) unexpected_read;
unexpected_accessed	unexpected_read
0	0
set @innodb_pages_read1= 
(select variable_value 
from information_schema.session_status 
where variable_name like 'innodb_pages_read');
set @innodb_pages_read_incr= (@innodb_pages_read1 - @innodb_pages_read0);
select @innodb_pages_read_incr > 1000, @innodb_pages_read_incr < 1500;
@innodb_pages_read_incr > 1000	@innodb_pages_read_incr < 1500
1	1
set @js='$analyze_output';
set @js=json_extract(@js, '$.query_block.nested_loop[0].table.r_engine_stats');
# This must just print pages_accessed. No page reads or prefetch reads,
# because the previous query has read all the needed pages into the
# buffer pool, which is set to be large enough to accomodate the whole
# table.
select @js;
@js
{"pages_accessed": NUMBER}
set @pages_accessed2= cast(json_value(@js,'$.pages_accessed') as INT);
select @pages_accessed2 = @pages_accessed;
@pages_accessed2 = @pages_accessed
1
drop table t1;
