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drop table if exists t1;
## Creating new table t1 ##
CREATE TABLE t1
(
id INT NOT NULL auto_increment,
PRIMARY KEY (id),
name VARCHAR(30)
);
## Creating another table t2 ##
CREATE TABLE t2
(
id INT NOT NULL auto_increment,
PRIMARY KEY (id),
name VARCHAR(30)
);
## Inserting records in both the tables ##
INSERT INTO t1(name) VALUES('Record_1');
INSERT INTO t1(name) VALUES('Record_2');
INSERT INTO t1(name) VALUES('Record_3');
INSERT INTO t1(name) VALUES('Record_4');
INSERT INTO t1(name) VALUES('Record_5');
INSERT INTO t2(name) VALUES('Record_1_1');
INSERT INTO t2(name) VALUES('Record_2_1');
INSERT INTO t2(name) VALUES('Record_3_1');
INSERT INTO t2(name) VALUES('Record_4_1');
INSERT INTO t2(name) VALUES('Record_5_1');
'#--------------------FN_DYNVARS_079_01-------------------------#'
## Setting max_join size value to 10 ##
SET @@session.max_join_size=10;
## This should work ##
SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id;
id name id name
1 Record_1 1 Record_1_1
2 Record_2 2 Record_2_1
3 Record_3 3 Record_3_1
4 Record_4 4 Record_4_1
5 Record_5 5 Record_5_1
'#--------------------FN_DYNVARS_079_02-------------------------#'
connect test_con1, localhost, root,,;
connection test_con1;
## Setting value of max_join_size ##
SET @@session.max_join_size=4;
## Since total joins are more than max_join_size value so error will occur ##
SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id;
ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay
'#--------------------FN_DYNVARS_079_03-------------------------#'
## Setting global value of variable ##
SET @@global.max_join_size=4;
connect test_con2, localhost, root,,;
connection test_con2;
## Verifying value of max_join_size ##
SELECT @@global.max_join_size;
@@global.max_join_size
4
## Since total joins are more than max_join_size value so error will occur ##
SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id;
ERROR 42000: The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay
## Dropping both the tables ##
Drop table t1, t2;
## Restoring values ##
SET @@global.max_join_size = DEFAULT;
SET @@session.max_join_size = DEFAULT;
disconnect test_con1;
disconnect test_con2;
|
