mariadb/mysql-test/r/query_cache.result.es
unknown d3c5c4997c Fixes to make mysql-test-run --embedded-server working
mysql-test/mysql-test-run.sh:
  Tests that can't be fixed now showed in the ignore-list
mysql-test/r/query_cache.result.es:
  test result renewed
mysql-test/r/select.result.es:
  test result renewed
mysql-test/r/type_blob.result.es:
  test result renewed
mysql-test/r/type_float.result.es:
  test result renewed
sql/sql_prepare.cc:
  time values sending fixed
tests/client_test.c:
  that doesnt work in embedded server
BitKeeper/etc/ignore:
  Added libmysqld/ha_archive.cc libmysqld/ha_example.cc libmysqld/ha_tina.cc to the ignore list
2004-12-02 16:08:17 +04:00

925 lines
20 KiB
JavaScript
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

set GLOBAL query_cache_size=1355776;
flush query cache;
flush query cache;
reset query cache;
flush status;
drop table if exists t1,t2,t3,t4,t11,t21;
drop database if exists mysqltest;
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
select * from t1;
a
1
2
3
select * from t1;
a
1
2
3
select sql_no_cache * from t1;
a
1
2
3
select length(now()) from t1;
length(now())
19
19
19
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
show status like "Qcache_inserts";
Variable_name Value
Qcache_inserts 1
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 1
drop table t1;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
create table t2 (a int not null);
insert into t2 values (4),(5),(6);
create table t3 (a int not null) engine=MERGE UNION=(t1,t2) INSERT_METHOD=FIRST;
select * from t3;
a
1
2
3
4
5
6
select * from t3;
a
1
2
3
4
5
6
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 2
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
insert into t2 values (7);
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t1;
a
1
2
3
select * from t1;
a
1
2
3
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 3
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
insert into t3 values (8);
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t3;
a
1
2
3
8
4
5
6
7
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
update t2 set a=9 where a=7;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t1;
a
1
2
3
8
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
update t3 set a=10 where a=1;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t3;
a
10
2
3
8
4
5
6
9
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
delete from t2 where a=9;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t1;
a
10
2
3
8
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
delete from t3 where a=10;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
drop table t1, t2, t3;
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
create table t2 (a int not null);
insert into t2 values (1),(2),(3);
select * from t1;
a
1
2
3
select * from t2;
a
1
2
3
insert into t1 values (4);
show status like "Qcache_free_blocks";
Variable_name Value
Qcache_free_blocks 2
flush query cache;
show status like "Qcache_free_blocks";
Variable_name Value
Qcache_free_blocks 1
drop table t1, t2;
create table t1 (a text not null);
create table t11 (a text not null);
create table t2 (a text not null);
create table t21 (a text not null);
create table t3 (a text not null);
insert into t1 values("1111111111111111111111111111111111111111111111111111");
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t11 select * from t1;
insert into t21 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t3 select * from t1;
insert into t3 select * from t2;
insert into t3 select * from t1;
select * from t11;
select * from t21;
show status like "Qcache_total_blocks";
Variable_name Value
Qcache_total_blocks 7
show status like "Qcache_free_blocks";
Variable_name Value
Qcache_free_blocks 1
insert into t11 values("");
select * from t3;
show status like "Qcache_total_blocks";
Variable_name Value
Qcache_total_blocks 8
show status like "Qcache_free_blocks";
Variable_name Value
Qcache_free_blocks 2
flush query cache;
show status like "Qcache_total_blocks";
Variable_name Value
Qcache_total_blocks 7
show status like "Qcache_free_blocks";
Variable_name Value
Qcache_free_blocks 1
drop table t1, t2, t3, t11, t21;
set query_cache_type=demand;
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
select * from t1;
a
1
2
3
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select sql_cache * from t1 union select * from t1;
a
1
2
3
set query_cache_type=2;
select sql_cache * from t1 union select * from t1;
a
1
2
3
select * from t1 union select sql_cache * from t1;
a
1
2
3
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 4
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
set query_cache_type=on;
reset query cache;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select sql_no_cache * from t1;
a
1
2
3
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
drop table t1;
create table t1 (a text not null);
select CONNECTION_ID() from t1;
CONNECTION_ID()
select FOUND_ROWS();
FOUND_ROWS()
0
select NOW() from t1;
NOW()
select CURDATE() from t1;
CURDATE()
select CURTIME() from t1;
CURTIME()
select DATABASE() from t1;
DATABASE()
select ENCRYPT("test") from t1;
ENCRYPT("test")
select LAST_INSERT_ID() from t1;
LAST_INSERT_ID()
select RAND() from t1;
RAND()
select UNIX_TIMESTAMP() from t1;
UNIX_TIMESTAMP()
select USER() from t1;
USER()
select benchmark(1,1) from t1;
benchmark(1,1)
explain extended select benchmark(1,1) from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 system NULL NULL NULL NULL 0 const row not found
Warnings:
Note 1003 select sql_no_cache benchmark(1,1) AS `benchmark(1,1)` from test.t1
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
create table t2 (a text not null);
insert into t1 values("1111111111111111111111111111111111111111111111111111");
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 4
show status like "Qcache_lowmem_prunes";
Variable_name Value
Qcache_lowmem_prunes 0
select a as a1, a as a2 from t1;
select a as a2, a as a3 from t1;
select a as a3, a as a4 from t1;
select a as a1, a as a2 from t1;
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 4
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
show status like "Qcache_lowmem_prunes";
Variable_name Value
Qcache_lowmem_prunes 2
reset query cache;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
select * from t1;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
drop table t1,t2;
create database mysqltest;
create table mysqltest.t1 (i int not null auto_increment, a int, primary key (i));
insert into mysqltest.t1 (a) values (1);
select * from mysqltest.t1 where i is null;
i a
1 1
create table t1(a int);
select * from t1;
a
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
select * from mysqltest.t1;
i a
1 1
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 3
drop database mysqltest;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
drop table t1;
create table t1 (a char(1) not null collate koi8r_general_ci);
insert into t1 values(_koi8r"<22>");
set CHARACTER SET koi8r;
select * from t1;
a
<EFBFBD>
set CHARACTER SET cp1251_koi8;
select * from t1;
a
<EFBFBD>
set CHARACTER SET DEFAULT;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 4
drop table t1;
create database if not exists mysqltest;
create table mysqltest.t1 (i int not null);
create table t1 (i int not null);
insert into mysqltest.t1 (i) values (1);
insert into t1 (i) values (2);
select * from t1;
i
2
use mysqltest;
select * from t1;
i
1
select * from t1;
i
1
use test;
select * from t1;
i
2
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
drop database mysqltest;
drop table t1;
create table t1 (i int not null);
insert into t1 (i) values (1),(2),(3),(4);
select SQL_CALC_FOUND_ROWS * from t1 limit 2;
i
1
2
select FOUND_ROWS();
FOUND_ROWS()
4
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
select * from t1 where i=1;
i
1
select FOUND_ROWS();
FOUND_ROWS()
1
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
select SQL_CALC_FOUND_ROWS * from t1 limit 2;
i
1
2
select FOUND_ROWS();
FOUND_ROWS()
4
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 7
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
select * from t1 where i=1;
i
1
select FOUND_ROWS();
FOUND_ROWS()
1
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 8
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
drop table t1;
flush query cache;
reset query cache;
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
select * from t1;
a
1
2
3
select * from t1;
a
1
2
3
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
insert delayed into t1 values (4);
select a from t1;
a
1
2
3
4
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
drop table t1;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
show global variables like "query_cache_min_res_unit";
Variable_name Value
query_cache_min_res_unit 4096
set GLOBAL query_cache_min_res_unit=1001;
show global variables like "query_cache_min_res_unit";
Variable_name Value
query_cache_min_res_unit 1008
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
create table t2 (a int not null);
insert into t2 values (1),(2),(3);
select * from t1;
a
1
2
3
select * from t1;
a
1
2
3
select * from t2;
a
1
2
3
select * from t2;
a
1
2
3
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 11
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
drop table t1;
select a from t2;
a
1
2
3
select a from t2;
a
1
2
3
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 12
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
drop table t2;
set GLOBAL query_cache_min_res_unit=default;
show global variables like "query_cache_min_res_unit";
Variable_name Value
query_cache_min_res_unit 4096
create table t1 (a int not null);
insert into t1 values (1);
select "aaa" from t1;
aaa
aaa
select "AAA" from t1;
AAA
AAA
drop table t1;
create table t1 (a int);
set GLOBAL query_cache_size=1000;
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 0
select * from t1;
a
set GLOBAL query_cache_size=1024;
Warnings:
Warning 1282 Query cache failed to set size 1024; new query cache size is 0
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 0
select * from t1;
a
set GLOBAL query_cache_size=10240;
Warnings:
Warning 1282 Query cache failed to set size 10240; new query cache size is 0
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 0
select * from t1;
a
set GLOBAL query_cache_size=20480;
Warnings:
Warning 1282 Query cache failed to set size 20480; new query cache size is 0
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 0
select * from t1;
a
set GLOBAL query_cache_size=40960;
Warnings:
Warning 1282 Query cache failed to set size 40960; new query cache size is 0
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 0
select * from t1;
a
set GLOBAL query_cache_size=51200;
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 51200
select * from t1;
a
set GLOBAL query_cache_size=61440;
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 61440
select * from t1;
a
set GLOBAL query_cache_size=81920;
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 81920
select * from t1;
a
set GLOBAL query_cache_size=102400;
show global variables like "query_cache_size";
Variable_name Value
query_cache_size 102400
select * from t1;
a
drop table t1;
set GLOBAL query_cache_size=1048576;
create table t1 (i int not null);
create table t2 (i int not null);
select * from t1;
i
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
create temporary table t3 (i int not null);
select * from t2;
i
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
select * from t3;
i
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
update t1 set i=(select distinct 1 from (select * from t2) a);
drop table t1, t2, t3;
use mysql;
select * from db;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
use test;
select * from mysql.db;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
create table t1(id int auto_increment primary key);
insert into t1 values (NULL), (NULL), (NULL);
select * from t1 where id=2;
id
2
alter table t1 rename to t2;
select * from t1 where id=2;
ERROR 42S02: Table 'test.t1' doesn't exist
drop table t2;
select * from t1 where id=2;
ERROR 42S02: Table 'test.t1' doesn't exist
create table t1 (word char(20) not null);
select * from t1;
word
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
load data infile 'TEST_DIR/std_data/words.dat' into table t1;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select count(*) from t1;
count(*)
70
drop table t1;
create table t1 (a int);
insert into t1 values (1),(2),(3);
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t1 into outfile "query_cache.out.file";
select * from t1 into outfile "query_cache.out.file";
ERROR HY000: File 'query_cache.out.file' already exists
select * from t1 limit 1 into dumpfile "query_cache.dump.file";
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
drop table t1;
create table t1 (a int);
insert into t1 values (1),(2);
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 0
select * from t1;
a
1
2
SET OPTION SQL_SELECT_LIMIT=1;
select * from t1;
a
1
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
SET OPTION SQL_SELECT_LIMIT=DEFAULT;
drop table t1;
flush query cache;
reset query cache;
flush status;
set GLOBAL query_cache_size=1048576;
create table t1 (a int not null);
insert into t1 values (1),(2),(3);
create table t2 (a text not null);
create table t3 (a text not null);
insert into t3 values("1111111111111111111111111111111111111111111111111111");
insert into t2 select * from t3;
insert into t3 select * from t2;
insert into t2 select * from t3;
insert into t3 select * from t2;
insert into t2 select * from t3;
insert into t3 select * from t2;
insert into t2 select * from t3;
insert into t3 select * from t2;
insert into t2 select * from t3;
insert into t3 select * from t2;
drop table t2;
create table t2 (a int not null);
insert into t2 values (1),(2),(3);
create table t4 (a int not null);
insert into t4 values (1),(2),(3);
select * from t4;
select * from t2;
select * from t1 as tt, t1 as ttt where tt.a=1 and ttt.a=2;
select * from t2;
select * from t4;
select * from t1 as tt, t1 as ttt where tt.a=1 and ttt.a=2;
select * from t2;
select * from t4;
select * from t1 as tt, t1 as ttt where tt.a=1 and ttt.a=2;
delete from t2 where a=1;
flush query cache;
select * from t3;
delete from t4 where a=1;
flush query cache;
drop table t1,t2,t3,t4;
set query_cache_wlock_invalidate=1;
create table t1 (a int not null);
create table t2 (a int not null);
select * from t1;
a
select * from t2;
a
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
lock table t1 write, t2 read;
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
unlock table;
drop table t1,t2;
set query_cache_wlock_invalidate=default;
CREATE TABLE t1 (id INT PRIMARY KEY);
insert into t1 values (1),(2),(3);
select * from t1;
id
1
2
3
create temporary table t1 (a int not null auto_increment
primary key);
select * from t1;
a
drop table t1;
drop table t1;
SET NAMES koi8r;
CREATE TABLE t1 (a char(1) character set koi8r);
INSERT INTO t1 VALUES (_koi8r'<27>'),(_koi8r'<27>');
SELECT a,'<27>','<27>'='<27>' FROM t1;
a б 'Б'='б'
<EFBFBD> <EFBFBD> 1
<EFBFBD> <EFBFBD> 1
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 1
set collation_connection=koi8r_bin;
SELECT a,'<27>','<27>'='<27>' FROM t1;
a б 'Б'='б'
<EFBFBD> <EFBFBD> 0
<EFBFBD> <EFBFBD> 0
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 2
set character_set_client=cp1251;
SELECT a,'<27>','<27>'='<27>' FROM t1;
a В 'в'='В'
<EFBFBD> <EFBFBD> 0
<EFBFBD> <EFBFBD> 0
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 3
set character_set_results=cp1251;
SELECT a,'<27>','<27>'='<27>' FROM t1;
a В 'в'='В'
<EFBFBD> <EFBFBD> 0
<EFBFBD> <EFBFBD> 0
show status like "Qcache_hits";
Variable_name Value
Qcache_hits 6
show status like "Qcache_queries_in_cache";
Variable_name Value
Qcache_queries_in_cache 4
DROP TABLE t1;
CREATE TABLE t1 (a int(1));
CREATE DATABASE mysqltest;
USE mysqltest;
DROP DATABASE mysqltest;
SELECT * FROM test.t1;
a
USE test;
DROP TABLE t1;
set character_set_results=null;
select @@character_set_results;
@@character_set_results
NULL
set character_set_results=default;
set GLOBAL query_cache_size=1355776;
create table t1 (id int auto_increment primary key, c char(25));
insert into t1 set c = repeat('x',24);
insert into t1 set c = concat(repeat('x',24),'x');
insert into t1 set c = concat(repeat('x',24),'w');
insert into t1 set c = concat(repeat('x',24),'y');
set max_sort_length=200;
select c from t1 order by c, id;
c
xxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxw
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxy
reset query cache;
set max_sort_length=20;
select c from t1 order by c, id;
c
xxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxw
xxxxxxxxxxxxxxxxxxxxxxxxy
set max_sort_length=200;
select c from t1 order by c, id;
c
xxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxw
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxy
set max_sort_length=default;
select '1' || '3' from t1;
'1' || '3'
1
1
1
1
set SQL_MODE=oracle;
select '1' || '3' from t1;
'1' || '3'
13
13
13
13
set SQL_MODE=default;
drop table t1;
create table t1 (a varchar(20), b int);
insert into t1 values ('12345678901234567890', 1);
set group_concat_max_len=10;
select group_concat(a) FROM t1 group by b;
group_concat(a)
1234567890
Warnings:
Warning 1260 1 line(s) were cut by GROUP_CONCAT()
set group_concat_max_len=1024;
select group_concat(a) FROM t1 group by b;
group_concat(a)
12345678901234567890
set group_concat_max_len=default;
drop table t1;
SET GLOBAL query_cache_size=0;