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9d2b259e23
and auto_increment keys
Problems:
1. ALTER TABLE ... ORDER BY... doesn't make sence if there's a
user-defined clustered index in the table.
2. using a secondary index is slower than using a clustered one
for a table scan.
Fixes:
1. raise a warning.
2. use the clustered index.
mysql-test/include/mix1.inc:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- test case.
mysql-test/r/innodb.result:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- results adjusted.
mysql-test/r/innodb_mysql.result:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- results adjusted.
mysql-test/r/join_outer_innodb.result:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- results adjusted.
sql/sql_select.cc:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- use the clustered index for a table scan (if any) as it's faster than
using a secondary index.
sql/sql_table.cc:
Fix for bug #26447: "ALTER TABLE .. ORDER" does not work with InnoDB
and auto_increment keys
- ALTER TABLE ... ORDER BY doesn't make sence if there's a
user-defined clustered index in the table. Ignore it in such cases
and raise a warning.
20 lines
888 B
Plaintext
20 lines
888 B
Plaintext
CREATE TABLE t1 (id int(11) NOT NULL PRIMARY KEY, name varchar(20),
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INDEX (name)) ENGINE=InnoDB;
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CREATE TABLE t2 (id int(11) NOT NULL PRIMARY KEY, fkey int(11),
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FOREIGN KEY (fkey) REFERENCES t2(id)) ENGINE=InnoDB;
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INSERT INTO t1 VALUES (1,'A1'),(2,'A2'),(3,'B');
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INSERT INTO t2 VALUES (1,1),(2,2),(3,2),(4,3),(5,3);
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EXPLAIN
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SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
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WHERE t1.name LIKE 'A%';
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index PRIMARY,name PRIMARY 4 NULL 3 Using where
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1 SIMPLE t2 ref fkey fkey 5 test.t1.id 1 Using where; Using index
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EXPLAIN
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SELECT COUNT(*) FROM t2 LEFT JOIN t1 ON t2.fkey = t1.id
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WHERE t1.name LIKE 'A%' OR FALSE;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 index NULL PRIMARY 4 NULL 5
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1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.fkey 1 Using where
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DROP TABLE t1,t2;
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