MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.

learn more… | top users | synonyms

2
votes
4answers
287 views

Does my table violate normalization rules?

I am developing an emulator for a game. My item table looks like this: -- ---------------------------- -- Table structure for `items` -- ---------------------------- DROP TABLE IF EXISTS `items`; ...
2
votes
3answers
3k views

innodb_buffer_pool_size not changed

I use MySQL 5.5.23-1~dotdeb.0 (Debian) and here is the relevant part of my.cnf default-storage-engine = innodb innodb_buffer_pool_size = 3G innodb_log_file_size = 256M innodb_thread_concurrency = 8 ...
2
votes
2answers
4k views

“Could NOT find Curses” error when installing MySQL from source

I am installing MySQL Server from the source distribution which I downloaded from: http://dev.mysql.com/downloads/mysql/#downloads. I have downloaded the file (mysql-5.5.19.tar.gz). I am using ...
2
votes
2answers
511 views

Does MySQL 5.5 support shared database with separate schema?

I am developing a SaaS based product using MySQL 5.5 as the backend database. I want to keep shared database for all the tenants, but separate a database schema of each tenant. There would be a single ...
2
votes
2answers
421 views

MySQL - How much physical space will be reduced by changing the column type?

Lets say I have the following table: CREATE TABLE `my_table` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `relationship_status` varchar(48) CHARACTER SET utf8 COLLATE ...
2
votes
1answer
154 views

Need some help with this query get all status and their associated comments of me and all my friends

I've several days dealing with this query but can't get it to works as I want. This post is related to this one Several values from different tables in which I tough found the solution but I was ...
2
votes
2answers
2k views

How to improve MySQL Server Performance..??

As a MySQL DBA most of the times we are supposed to optimize a poorly performing MySQL Servers. Now my question is where to start from like we will need to find out many things as 1.Find the ...
2
votes
2answers
3k views

MySQL Table level Replication

I have 3 servers, say A,B &C. All have the equivalent data(same data). Now what I want is to make A as the master and B,C the slaves. But the scenario is that I only want to replicate some of the ...
2
votes
4answers
227 views

Aggregate query optimization

Could you please help me to optimize this query - currently it takes ~4 minutes to run this query. It looks like keys: ip and timestamp are non-unique so shall I add some indexes? mysql> EXPLAIN ...
2
votes
1answer
128 views

Is there a way to achieve Workload Management in MySQL?

Is there a way to set up Workload Management in MySQL (in particular v5.5 on AWS RDS)? By Workload Management I mean the functionality implemented in e.g. Teradata, RedShift that allows ...
2
votes
3answers
751 views

how to install mysql on mac?

My Mac runs Mac OS X, version 10.7.5., so it's a 64 bit system. First, I downloaded mysql-5.5.28-osx10.6-x86_64.dmg. Then I double clicked mysql-5.5.28-osx10.6-x86_64.dmg, it's mounted, and shows ...
2
votes
3answers
1k views

MySQL backup with no downtime

I'm running a M/S replication of MySQL 5.5 / innoDB (over ubuntu). My DB is pretty large: ~250GB. I'm looking for a backup tool/service that will do the following: full backup no downtime / locks ...
2
votes
1answer
22 views

Mysql INSERT INTO .. ON DUPLICATE KEY UPDATE

I'm trying to do the following query in mysql 5.5 INSERT INTO countingTable( image_count, article_id ) SELECT COUNT( article_id ) AS sum, article_id FROM imageTable ON DUPLICATE KEY UPDATE ...
2
votes
2answers
423 views

How to SELECT rows with time duration stored in varchar column?

There is a column in table defined like this : duration varchar(10) It has value for duration of a MP3 file stored in it like : 52:19 (Minutes : Seconds) How can I create a SQL query, for ...
2
votes
1answer
86 views

Need to Rewrite/optimize Slow Query

I have a query with following explain plan EXPLAIN SELECT COUNT(applicant.id) as applicantCount, application.name,applicant.application_id,application.id FROM applicant LEFT JOIN application ...
2
votes
3answers
7k views

How to Restore data from binary log

I am trying to restore some lost data , but I am not having its backup .So I am trying to restore from the binary log .Please explain how to restore from the binary log in mysql .
2
votes
2answers
2k views

mysql 5.5 corrupt - missing temporary table

One of our mysql instances crashed and failed to start: 120422 10:04:13 InnoDB: Error: trying to open a table, but could not InnoDB: open the tablespace file './databasename/#sql-29f6_45.ibd'! ...
2
votes
2answers
483 views

Any problem will all InnoDB and one MyISAM table?

I have a MySQL 5.5 DB with all InnoDB tables. For some reason, one of the developers decided to create a MyISAM table. It is a log table for user sessions. I don't see why we should mix in a MyISAM ...
2
votes
1answer
54 views

Auto_increment value needs to be set as S1

Hi I need to set auto increment for a table as S1. I tried by altering the table and also by creating by new table I am aware how to set auto_increment but when i try to set auto increment as S1 i am ...
2
votes
2answers
87 views

How to monitor InnoDB Disk I/O using Server Status Variables?

This question is extension of my previous question "How to monitor InnoDB Disk I/O Required for MySQL? " As mention in my previous question i want to count total number of disk i/o per query, but ...
2
votes
2answers
34 views

Mysql used key changes between two consecutive EXPLAINs

I have a huge unmaintained innodb table (~1.5billion rows), I just started to try to query it. I write && instead of AND once; and surprise! it uses different key! EXPLAIN EXTENDED SELECT * ...
2
votes
1answer
45 views

Unknown column error with an index

I created a simple index associated with a timestamp column CREATE TABLE `data` ( `id` INT(11) UNSIGNED NOT NULL, `ticker` VARCHAR(16) NOT NULL COLLATE 'utf8_unicode_ci', `comment` TEXT ...
2
votes
1answer
1k views

MySQL: Alter Table on very active table gives “Waiting for table metadata lock”

At my work, we've recently upgraded to MySQL 5.5 and since then, have been bitten a few times by the new (and intended) behavior of metadata locking. Basically, whenever we run an ALTER TABLE ...
2
votes
1answer
1k views

Recover the disk space after deleting rows from table

I deleted millions of rows from one of the table with innodb engine. I know that I need to run optimize table to recover the space. But running that will cause lock on the table, which will affect the ...
2
votes
1answer
304 views

datetime vs timestamp in mysql 5.5

What is the difference between datetime and timestamp in MySQL with respect to data being inserted from different timezones? Does anyone have any clues on this? I have a situation where I am trying ...
2
votes
1answer
262 views

select count(*) in mysql 5.5 innodb— rewrite advice?

I need advice on how to rewrite a select count(*) query for innodb tables mysql 5.5. in new environment its very slow... select count(*) from mails3 join questions using (question_id) where ...
2
votes
1answer
188 views

How can I disable utf8mb4 entirely on MySQL 5.5?

I know you're not supposed to do this, but I have a MySQL 5.5 master and a MySQL 5.1 replication slave. That's supposed to be okay, unless I do something stupid like use utf8mb4 that isn't supported ...
2
votes
2answers
3k views

Why max_allowed_packet is larger in mysqldump than mysqld in my.cnf?

If you look at the sample config such as /usr/share/mysql/my-large.cnf, you will find.. [mysqld] max_allowed_packet = 1M [mysqldump] max_allowed_packet = 16M What is the point? Because when you ...
2
votes
1answer
1k views

Issue with connecting to the mysql database

We have an outstanding issue with VCC in chicago, there is an issue connecting to the mysql database If an agent does a refresh of the monitor they will be logged out. This is the error we ...
2
votes
1answer
381 views

Does mysqld wait for init-script code to complete before opening the instance?

I'm trying to automate the execution of an application code at MySQL startup. The init-file server option seems handy and I need to know if mysqld waits for all the code in the init-file to complete ...
2
votes
1answer
271 views

Restriction on self referencing on insert in MYSQL?

How to restrict insert on adding self referencing rows in a recursive relation table (a table contains foreign key points itself). mysql> SELECT * FROM Employee; ...
2
votes
1answer
735 views

Extract some columns data from one table and insert into multiple tables

I have a table with 16,000 records and need to get out some columns and then insert values in multiples tables. For example, suppose I have the following tables tbl_1: id, name, lastname tbl_2: id, ...
2
votes
1answer
438 views

“set-variable = innodb_thread_concurrency=4” or “innodb_thread_concurrency=4”

Based on this question, the asker wrote: set-variable = innodb_buffer_pool_size=2M set-variable = innodb_additional_mem_pool_size=500K set-variable = innodb_log_buffer_size=500K set-variable = ...
2
votes
1answer
4k views

How to grant access for multiple tables to a user in MySQL DB?

I have mysql db named "greats" with four tables as below +---------------------+ | Tables_in_greatstat | +---------------------+ | log | | sitedet1 | | siteindex ...
2
votes
1answer
249 views

mysql emits BINLOG rows even though binlog_­format=­STATEMENT

We have MySQL 5.5 installed, we have the binlog_format=STATEMENT (the default) According to the MySQL Documentation, the binary log should contain SQL statements only, but we still see BINLOG rows in ...
2
votes
1answer
3k views

Is there a PPA for MySQL 5.5 for ubuntu 10.10 and 11.10?

I want to install MySQL server 5.5 on ubuntu 10.10 and 11.10 servers but have not yet found a problem free PPA or installation method as of yet. Has anyone managed to do this with the said versions of ...
2
votes
1answer
1k views

How to upgrade MySQL to a New version..?

I have installed mysql using the package management system.I am using ubuntu machine. After that i have very well configured the server for InnoDB and other server related parameters. I am using the ...
2
votes
1answer
3k views

Fixing MySQL errors recorded in error logs

Below is the extract of the most common lines of error being recorded in error logs on my PC: 110905 16:16:54 [Note] Plugin 'FEDERATED' is disabled. 110905 16:16:54 InnoDB: The InnoDB memory heap is ...
2
votes
2answers
41 views

Cannot configure nor start MySQL

On a brand new Kubuntu 14.04 install, I ran sudo aptitude install mysql-server-core-5.6. The install could not complete due to dependencies of some KDE packages on mysql-server-core-5.5, which would ...
2
votes
1answer
33 views

WHERE attribute having two relation lines in the same SQL

I have a database designed with tree tables: checklist (id, name) tag (id, name) checklist_tag (checklist_id - FK, tag_id - FK) Running this SQL: SELECT cc.id as checklist_id, cc.name as ...
2
votes
1answer
272 views

Space not reclaimed after dropping MyISAM table

I just dropped a rather large MyISAM table (~4 gb); it was 350k rows with about 11k of data per row. However, when I run df -h on my database server, I am still at 100% disk usage, so much so that I ...
2
votes
3answers
88 views

How to update cust_id from Customer table to order table Cust_id field while inserting customer name using trigger

I have two tables 1. Customer_details and 2. Order_details. 1.Customer_details table -->fields--> Cust_Id(Primary Key) and Customer_Name, 2.Order_details table --> fields-- Ord_Id(Primary ...
2
votes
3answers
327 views

Getting 0KB of size file while backup mysql database using mysql dump

I am using below code to backup my database using php script but I am getting 0KB size file. How can I backup my full database with all routines and functions? $dbhost = 'localhost'; $dbuser = ...
2
votes
1answer
362 views

How to modify `proxies_priv` in MySQL

I recently received a warning from MySQL that stated: [Warning] 'proxies_priv' entry '@ root@serverdomain' ignored in --skip-name-resolve mode. I looked in mysql.proxies_priv and there is ...
2
votes
1answer
244 views

MySQL / Fusion IO Configuration Question

I need a little configuration optimization. I think what I have is pretty good but feel like there's still room for improvement. Current Config [mysqld] user=mysql datadir=/var/lib/mysql ...
2
votes
2answers
639 views

changing TEMPORARY TABLE default collation

when I use CREATE TEMPORARY TABLE to create a temporary table, the collation of this table is utf8_unicode_ci by default. why by default it is utf8_unicode_ci? How can I change the default?
2
votes
2answers
3k views

MySQL 5.5 High CPU Usage

I have been working with a client with high traffic website(500k visitors and 600-800 active users at any given time). This uses wordpress and the DB is using MyISAM engine. The problem we had was ...
2
votes
1answer
57 views

Make sure slave has finished reading from master

I am planning to have a master-slave system in which occasionally the master and slave will reverse roles. To do this, I will stop further updates to master, and redirect traffic to the slave. But, ...
2
votes
1answer
116 views

MySQL Subquery hangs / terrible perfomance

I am using MySQL 5.5.16 @ CentOS. Please have a look at this query: SELECT inventory_ID, ( SELECT price_brutto FROM _inventory_prices ...
2
votes
1answer
76 views

System to track what Zip Codes my vendors service

I am designing a table configuration that will contain all of the zip codes in the United States. I have a .csv file of all the zip codes in the U.S., so thats at least a start. This will end up as a ...