Tagged Questions
2
votes
0answers
47 views
SELECT … FOR UPDATE from one table in multiple threads
I need a little help with SELECT FOR UPDATE (resp. LOCK IN SHARE MODE).
I have a table with around 400 000 records and I need to run two different processing functions on each row.
The table ...
2
votes
0answers
41 views
IntegrityError when trying to delete User
I'm getting an IntegrityError when trying to delete a User:
IntegrityError: (1451, 'Cannot delete or update a parent row:
a foreign key constraint fails (`mydb`.`app_object`,
CONSTRAINT ...
1
vote
0answers
37 views
Usage of innodb and myisam tables together
I have a software that writes logs to the database and these logs will be stored about 2-3 months. A few people want to query these logs at any time they want. System writes avg 5000 rows per second ...
1
vote
0answers
65 views
Mysql Innodb hangs on Table Level Lock
I have a production system with 10,000 queries/second. I recently updated to MySQL v5.5 and am now facing an issue: my InnoDB tables get locked all of a sudden.
Waiting for table level lock | UPDATE ...
1
vote
0answers
38 views
best practices for table partitioning - mysql 5.5
I have a mysql 5.5 server with a big (~150M records) innodb table that I want to partition.
How can I determine the optimal number of partitions for the table?
The table is a "many-to-many" ...
1
vote
0answers
24 views
Change FOREIGN KEY action on large table
I have a large table (large enough to break my query) and I need to change ON DELETE from RESTRICT to CASCASDE, the problem is when I execute query like this:
ALTER TABLE my_table DROP FOREIGN KEY ...
1
vote
0answers
23 views
MySQL InnoDB Changing Referential Actions ON DELETE CASCADE
Is there a faster way to add a CASCADE rule to an existing foreign key than dropping and adding the constraint?
SET foreign_key_checks = 0;
ALTER TABLE drop foreign key ...;
ALTER TABLE add foreign ...
1
vote
0answers
44 views
Optimal numbering of rows in subgroups in MySQL InnoDB
I need to reduce the number of entries per user in a table, leaving only the latest ones (say 10) for each user. It requires numbering of entries in a subgroup (defined by user_id) what is quite a ...
1
vote
0answers
86 views
mysql IO read rate is very slow
I have a very simple query
select * from ap_statistic
running in my servers. The servers have the same hardware and software configuration (CPU 8 core, mem :32G, OS: redhat 5.5, mysql version: 5.1 ...
1
vote
0answers
43 views
Is it possible to deal with 2 table engines at the same time? InnoDB with MyISAM
I was trying to make a full-text search for a simple engine and i have realized i can not do it with InnoDB.
Now, i was wondering if I can convert only that table to MyISAM and still working with the ...
1
vote
0answers
54 views
NHibernate, MySQL (InnoDB) and locking rows
I have got a counter in a database table (Mysql with InnoDB). On the client I am using NHibernate.
What is the recommended way to update the counter in a safe manner (just one client is able to ...
1
vote
0answers
96 views
mysql 5.6 RC InnoDB full text search slowness
As mysql 5.6 is RC I tried to convert my myisam tables to innodb because I read that the FTS engine is quite faster and stronger and FTS was the only thing holding me back on myisam.
To my ...
1
vote
0answers
71 views
MySQL Query Optimization (7.6s to Run)
Heres my query:
SELECT `users`.`id`, `users`.`username`, `users`.`profile_picture_url`, `users`.`credits_offered`, `users`.`country_id`, `users`.`user_level`, `users`.`credits`
FROM `users`
LEFT JOIN ...
1
vote
0answers
341 views
mysql can't drop corrupt innodb table
So I'm dealing with a MySQL server which ran out of disk space and has mostly InnoDB tables which of course got corrupted. I'm trying to drop and recreate the damaged tables but MySQL won't let me do ...
1
vote
0answers
204 views
mysqli row size too large
i am trying to insert data into a mysql table that is using the innodb storage engine and am getting this error:
Mysqli statement execute error : Row size too large. The maximum row size for the used ...
