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drop table if exists t1, t2;
create table t1 (
a int not null auto_increment,
b char(16) not null,
primary key (a),
key (b)
);
create table t2(
a int not null auto_increment,
b char(16) not null,
primary key (a),
key (b)
);
insert into t1(b) values
('test0'),
('test1'),
('test2'),
('test3'),
('test4'),
('test5'),
('test6'),
('test7');
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
insert into t2(b) select b from t1;
insert into t1(b) select b from t2;
select count(*) from t1;
count(*)
33448
select count(*) from t2;
count(*)
20672
flush tables;
flush status;
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
select count(*) from t1 where b = 'test1';
count(*)
4181
show status like "key_read%";
Variable_name Value
Key_read_requests 217
Key_reads 45
select count(*) from t1 where b = 'test1';
count(*)
4181
show status like "key_read%";
Variable_name Value
Key_read_requests 434
Key_reads 45
flush tables;
flush status;
select @@preload_buffer_size;
@@preload_buffer_size
32768
load index into cache t1;
Table Op Msg_type Msg_text
test.t1 preload_keys status OK
show status like "key_read%";
Variable_name Value
Key_read_requests 581
Key_reads 581
select count(*) from t1 where b = 'test1';
count(*)
4181
show status like "key_read%";
Variable_name Value
Key_read_requests 798
Key_reads 581
flush tables;
flush status;
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
set session preload_buffer_size=256*1024;
select @@preload_buffer_size;
@@preload_buffer_size
262144
load index into cache t1 ignore leaves;
Table Op Msg_type Msg_text
test.t1 preload_keys status OK
show status like "key_read%";
Variable_name Value
Key_read_requests 10
Key_reads 10
select count(*) from t1 where b = 'test1';
count(*)
4181
show status like "key_read%";
Variable_name Value
Key_read_requests 227
Key_reads 52
flush tables;
flush status;
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
set session preload_buffer_size=1*1024;
select @@preload_buffer_size;
@@preload_buffer_size
1024
load index into cache t1, t2 key (primary,b) ignore leaves;
Table Op Msg_type Msg_text
test.t1 preload_keys status OK
test.t2 preload_keys status OK
show status like "key_read%";
Variable_name Value
Key_read_requests 587
Key_reads 587
select count(*) from t1 where b = 'test1';
count(*)
4181
select count(*) from t2 where b = 'test1';
count(*)
2584
show status like "key_read%";
Variable_name Value
Key_read_requests 938
Key_reads 613
flush tables;
flush status;
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
load index into cache t3, t2 key (primary,b) ;
Table Op Msg_type Msg_text
test.t3 preload_keys error Table 'test.t3' doesn't exist
test.t2 preload_keys status OK
show status like "key_read%";
Variable_name Value
Key_read_requests 355
Key_reads 355
flush tables;
flush status;
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
load index into cache t3 key (b), t2 key (c) ;
Table Op Msg_type Msg_text
test.t3 preload_keys error Table 'test.t3' doesn't exist
test.t2 preload_keys error Key column 'c' doesn't exist in table
test.t2 preload_keys status Operation failed
show status like "key_read%";
Variable_name Value
Key_read_requests 0
Key_reads 0
drop table t1, t2;
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