Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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10.4.7, 10.3.25
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None
Description
On source server:
CREATE TABLE simple (
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id int(10) unsigned NOT NULL AUTO_INCREMENT,
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val int(10) unsigned DEFAULT NULL,
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PRIMARY KEY (id), ENGINE=InnoDB;
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insert into simple(val) values(1);
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On spider server:
create server s31689 foreign data wrapper mysql options (
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host '10.0.0.241' ,
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database 'd31689' ,
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user 'spider' ,
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password 'spider' ,
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port 3306 );
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CREATE TABLE simple (
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id int(10) unsigned NOT NULL AUTO_INCREMENT,
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val int(10) unsigned DEFAULT NULL,
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PRIMARY KEY (id), ENGINE=SPIDER
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DEFAULT CHARSET=utf8
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COMMENT='srv "s31689", table "simple"'
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Query OK, 0 rows affected (0.026 sec)
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MariaDB [d31689]> select * from simple;
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+----+------+
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| id | val |
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+----+------+
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| 1 | 1 |
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+----+------+
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1 row in set (0.015 sec)
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MariaDB [d31689]> select id, 0 as const, val from simple;
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+----+-------+------+
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| id | const | val |
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+----+-------+------+
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| 1 | 0 | 0 |
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+----+-------+------+
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1 row in set (0.002 sec)
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Attachments
Issue Links
- causes
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- Closed
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- relates to
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- Closed
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Activity
igor,
When executing a query like "select max(id), 0 as const, group_id from ...", there are 3 columns(items) in Query->select at handlerton->create_group_by(). After that, MariaDB makes a temporary table with 2 columns.
I heard from Sergei that const items in select clause are skipped for columns of temporary table of group by handler.
So I fixed that Spider skips const items in select clause at executing group by handler. 4d47d73
Is it ok for you?
Kentoku,
The patch is ok. I would suggest only to add the following to your test case:
SELECT id, 0 AS const, val FROM tbl_a;
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id const val
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1 0 1
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+SELECT 1+2, id, 0 AS const, val, val+10, (SELECT tbl_a.val+1 FROM tbl_a) AS sq
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+FROM tbl_a;
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+1+2 id const val val+10 sq
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+3 1 0 1 11 2
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+INSERT INTO tbl_a (val) VALUES (2), (1);
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+SELECT val+10, 0 AS const, val, (SELECT tbl_a.val+1 FROM tbl_a LIMIT 1) AS sq
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+FROM tbl_a GROUP BY val;
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+val+10 const val sq
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+11 0 1 2
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+12 0 2 2
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+SELECT MAX(id) AS m, 0 AS const, val, (SELECT tbl_a.val+1 FROM tbl_a LIMIT 1) AS sq
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+FROM tbl_a GROUP BY val;
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+m const val sq
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+3 0 1 2
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+2 0 2 2
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connection child2_1;
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SELECT argument FROM mysql.general_log WHERE argument LIKE '%select %';
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When executing a query like "select id, 0 as const, val from ...", there are 3 columns(items) in Query->select at handlerton->create_group_by(). After that, MariaDB makes a temporary table with 2 columns.
How can I know which columns are skipped for the temporary table?