[MDEV-8460] Select query with 'where' and 'order by' on Spider engine table returns null records Created: 2015-07-14  Updated: 2021-08-13  Resolved: 2021-08-13

Status: Closed
Project: MariaDB Server
Component/s: Partitioning, Storage Engine - Spider
Affects Version/s: 10.0.20
Fix Version/s: N/A

Type: Bug Priority: Major
Reporter: Masanao Kitora Assignee: Nayuta Yanagisawa (Inactive)
Resolution: Won't Fix Votes: 0
Labels: not-10.2, not-10.6
Environment:

CentOS 6.5 (x64)


Attachments: File my.cnf     Text File result.txt     Text File spidertest.sql    

 Description   

We created Spider engine table using partitioning by primary key.
And tried to select from the table by query with 'WHERE' and 'ORDER BY' query.
But returned result rows contain null value columns while such data does not exist.
As I checked past issues , MDEV-6301 is simular issue.
But it is checked as CLOSED.

I attached reproducing script.
If more information is necessary, please let me know.



 Comments   
Comment by Elena Stepanova [ 2015-07-14 ]

Hi,

Could you please paste the result set you are getting, and your cnf file(s)?

I've got this, looks okay, no NULLs:

pkey	stat	testtext
	aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa	testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest

Comment by Masanao Kitora [ 2015-07-14 ]

I attached result.txt and my.cnf.
In result pkey field is NULL while stat and testtext fields are not null which were used in the query.
Maybe my sample is not good...

Comment by Elena Stepanova [ 2015-07-14 ]

Thanks, the sample is okay. I just noticed that the result set that I pasted also contains an empty pkey, so I'm getting the same problem sporadically:

elenst@wheezy-64:~/git/10.1$ mysql -uroot test -e "use spidertest; select * from spidertest where stat like 'a%' order by testtext limit 2;"
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| pkey | stat                                                                                                                                                                                                                                                       | testtext                                                                                                                                                                                                 |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|      | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
elenst@wheezy-64:~/git/10.1$ mysql -uroot spidertest -e "select * from spidertest where stat like 'a%' order by testtext limit 2;"
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| pkey | stat                                                                                                                                                                                                                                                       | testtext                                                                                                                                                                                                 |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 1    | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Comment by Elena Stepanova [ 2015-07-14 ]

So, I'm getting it with the provided spidertest.sql.
The last query in the file is

select * from `spidertest` where `stat` like 'a%' order by `testtext` limit 2;

It can be run multiple times, the result is still the same, pkey is empty.
However, certain operations make the problem switch away, e.g. FLUSH TABLES.

MariaDB [(none)]> use spidertest;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
 
Database changed
MariaDB [spidertest]> select * from `spidertest` where `stat` like 'a%' order by `testtext` limit 2;
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| pkey | stat                                                                                                                                                                                                                                                       | testtext                                                                                                                                                                                                 |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
|      | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)
 
MariaDB [spidertest]> flush tables;
Query OK, 0 rows affected (0.00 sec)
 
MariaDB [spidertest]> select * from `spidertest` where `stat` like 'a%' order by `testtext` limit 2;
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| pkey | stat                                                                                                                                                                                                                                                       | testtext                                                                                                                                                                                                 |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 1    | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttesttest |
+------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.02 sec)

Comment by Nayuta Yanagisawa (Inactive) [ 2021-08-13 ]

The bug does not reproduces on 10.2. So, I close it.

Generated at Thu Feb 08 07:27:19 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.