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

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2answers
165 views

avoiding unique key collisions across tables

This might be related to the idea of data warehousing, but i'm not sure, though it is extreme theory. We have a table where records get written to first, let's call it tbl_recording which looks like: ...
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1answer
130 views

Update the host field in Grant privileges in mysql

I have an existing table and I want to update host part in privileges using Grant command mysql> show grants -> ; ...
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1answer
104 views

Database design [closed]

I have tables college and department. In college, I have serial-number and college-names, In department, i have nos, college-names and department-name. My challenge is that having a repeated ...
0
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1answer
513 views

SQL Query is sometimes slow, sometimes fast

I have two hosts, one with my rails app, one with my MySQL database. Going through my rails Logfile I can see that sometimes queries take much more time than the same query at other times. Think 200ms ...
2
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0answers
94 views

Understanding Indexes and using them better

I've been spending some time trying to optimise our MySQL queries that we use which essentially joins one table with 2 million rows onto another which has 1-2 million. I know MySQL is able to easily ...
1
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1answer
206 views

Squeezing Maximum Out Of My Server

I have a dedicated server only built to hold MySQL databases. Currently I have a database that has 173 million records and increasing by 5-15+ million records very day. My question is what and why I ...
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0answers
39 views

Is there any way to set server-wide and schema-wide default row formats for InnoDB tables in MySQL?

Is there a way to set server-wide and database-wide default row formats? Currently it seems that I must specify ROW_FORMAT in CREATE TABLE or ALTER TABLE statements. Am I reading the documentation ...
0
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0answers
105 views

How to set up a pivot table view?

I have three tables: Entry Manager Employee The Entry table has as date field and a bunch of other fields about the entry including the emp_id. Manager Table has columns: Manager_id ...
1
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0answers
488 views

Fastest way to perform simple operations on 1 million rows

I have a simple table with more than 1 million rows in an InnoDB MySQL table. Here are the steps that I need to perform on each row: SELECT * FROM tbl where work_done=0 make some data processings ...
0
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1answer
39 views

Migrating database with views trough phpMyAdmin causes error in second host

I'm trying to migrate a database which contains some views and I'm doing trough phpMyAdmin export feature. MySQL version on servers are: Server to migrate: Server version: 5.5.34-0ubuntu0.12.04.1 ...
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0answers
27 views

Anyone know the fix for an older innodb inspection query

This post talked about an information_schema query to give you a nice report of how much percentage wise indexes are fitting into the buffer pool The query looked like > SELECT `schema` ...
11
votes
2answers
977 views

Fastest way to change a 600GB table indexed key datatype from INT to BIGINT

I need to change a datatype from INT to BIGINT in a 600GB MySQL table. The column has a unique index. I might be good with unsigned INT, but I assume changing to that or BIGINT will be pretty much ...
0
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1answer
106 views

How to make slave is in sync with master in tungsten replication?

we are using Tungsten master to slave replication in MySQL. we have configured this setup very long back. from last week onwards slave is in lagging with master around 5 to 10 binary files. we have ...
0
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1answer
294 views

Replication - Binary log parsing(Tableid generation, ON DELETE CASCADE handling, Changed columns for update event)

I am using MySQL 5.5 with InnoDB engine. I have set binlog format as row-based replication. I have some doubts regarding replication: 1) How is the tableID generated? Is it stored somewhere? 2) ...
1
vote
1answer
319 views

Two different MYSQl instances on same machine?

I have MySQL 5.6 installed (Linux). /var/lib/mysql /etc/my.cnf I have a cold backup that I am recovering: /var/lib/mysql_backup /etc/mybackup.cnf In April I was able to get the backup started ...
0
votes
1answer
823 views

Restoring a single database from mysql enterprise full backup

I am having command to restore all databases from full dump taken by enterprise full backup .Can anyone help me how to restore single database from full dump .
1
vote
1answer
103 views

How to prevent Cartesian joins when value can be in either field?

I have a table of articles where the same article may be presented to different audiences with slightly altered text depending on the user's access level. When this occurs, the article will have the ...
1
vote
1answer
109 views

Change normal user to admin in MySQL

I have set up a MySQL database. My problem now is I can't add new users with the user I have created. I try to grant access but I can't still add new users to my system. I use Workbench to add new ...
0
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1answer
32 views

Count issue in Mysql

I query a table SELECT COUNT(*) FROM sf_guard_user_group return count 1 but table has total 28 records. But if I test it via putty from another machine, it shows count 28. Help to sort out.
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2answers
681 views

How to enable the Federated/FederatedX storage engine on MariaDB 5.5?

I upgraded from MySQL 5.1 to MariaDB 5.3 and then to 5.5 on a Windows machine. Everything works well, except I can't enable the federated storage engine. With MySQL 5.1 and MariaDB 5.3, I just added ...
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0answers
184 views

how to update current row value by selecting previous row value in php mysql

How can i update data of current row with selecting data of previous row in php mysql. I have tried following query but it showing me error. update sales_tracking set sales_tracking.opening_units = ( ...
0
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1answer
36 views

Cannot create stored procedure

I have the following piece of statement entered into MySQL5.6 Command Line Client. However, the following error was received. I haven't even been able to add in END// Delimiter; after the select ...
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0answers
45 views

How to move partitions between filesystems

We have ~9TB MySQL database which consists from a few tables which are partitioned by day. Sum of daily information is ~20GB. Database is practically write only. There are at most tens of queries ...
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0answers
23 views

Cloning rows with minor changes

I am attempting to clone a row in the database, not that difficult. However the row has a reference to another row in the database that when inserted needs to use a different value, perhaps provided ...
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0answers
28 views

Accessing Database from Slave server

I have an application running in one server eg: My Server's Ip is 192.168.10.10, and I have the MySQL database server in the same machine. The application connects database server as localhost. ...
3
votes
1answer
233 views

How to store static list of hashes in MySQL effectively?

Problem: I have a list of pairs (md5_hash, id). I want to store the data in MySQL and I want to make queries like this SELECT id FROM table WHERE md5_hash = <some_hash> The number of pairs ...
2
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1answer
48 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 ...
5
votes
1answer
706 views

Possibilities to speed up InnoDB INSERTs and UPDATEs

My website retains user sessions in an innodb table. This usually works well, but a few hundred times a day, the INSERT and particularly the UPDATE statements run slower. I'm monitoring when, and it ...
0
votes
1answer
87 views

How to drop a column named 'column'? [closed]

I need to delete a column named "column" form a table but the standard: mysql> ALTER TABLE table_name DROP COLUMN 'column'; returns: ERROR 1064 (42000): You have an error in your SQL syntax; ...
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1answer
102 views

Using an enum index to limit records

A common issue, just not sure on the keywords. I have a table of assessments (14k+ records). Each assessment can be in many different states ('draft', 'proofing', 'amends', etc... and 'done'). Most ...
0
votes
1answer
166 views

MySQL 1366 Error on Replication Slave

I've got two pairs of servers (each identical hardware and OS) with replication running on both pairs. Running MySQL 5.5.34 on Windows Server 2008 R2. I'm trying to track down a problem that has ...
1
vote
1answer
82 views

How and where do I upload a mysql database?

I am new to Ubuntu (server edition) and mysql. How do I upload (import) an existing database with a MYSQL or (mysql.zip) extension that was downloaded from a web host (cPanel?) I do not have any of ...
1
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2answers
327 views

How can I return column names in dot notation in MySQL?

I want to return column names into a table. But I also want to avoid redundancies like 'id' and 'id'. I did: INSERT INTO columns(name) SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE ...
2
votes
1answer
138 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 ...
0
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1answer
107 views

how auto_increment work in mysql

im confused here , i create a table and have 2 columns id and name. Now id is primary key , not null and auto increment. Suppose i fire: insert into table (name) values('test'); this will give me: ...
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 ...
0
votes
1answer
351 views

How to update a table by count from another table?

I have two tables as CREATE TABLE country_statistics ( id int(11) NOT NULL AUTO_INCREMENT us int(11), uk int(11), ca int(11), PRIMARY KEY(id) ) ENGINE=InnoDB DEFAULT CREATE TABLE entries ( id ...
0
votes
1answer
55 views

MySQL Partitioning: why it's not taking appropriate partition

DROP TABLE temp; CREATE TABLE `temp` ( `CallID` bigint(8) unsigned NOT NULL, `InfoID` bigint(8) unsigned NOT NULL, `CallStartTime` datetime NOT NULL, ...
0
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0answers
90 views

Query Execution Plan for MySQL

In Microsoft SQL Server you can see Execution Plans for queries to see how a query is executed, what joins take the most time and see any missing indexs now i want to do the same for MySQL scripts ...
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1answer
69 views

Create user for alternate port

I am running a private MySQL instance on WebFaction WebFaction is a shared host who provides both for their public MySQL instance and for your own private MySQL instance. The private instance is a ...
0
votes
4answers
3k views

MySQL gives me:“Can't open and lock privilege tables: Table 'host' is read only”

I am facing problem restoring a MySQL database. My primary database was MySQL 5.1 and now I am trying to copy it to MySQL 5.5. The database was backed up by using Xtrabackup. I am using Ubuntu ...
0
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0answers
319 views

mysql doesnt have write access in data dir?

I am running a MySQL on my Windows 7 64 bit development machine at work and I can't seem to get around a database corruption issue. In my unit tests it is telling me that the storage engine (which is ...
0
votes
2answers
492 views

How to use OR in query with priority?

In a simple query like SELECT * FROM table WHERE id='x' OR id='y' How to give a priority to get only one of the WHERE clauses? I mean getting rows with id='x'. Only if there is no row, get row ...
1
vote
1answer
118 views

Upgrading MySQL 5.1 to 5.5 - All tables gone [closed]

I'm trying to upgrade from MySQL 5.1 to MySQL 5.5. I followed the instructions here: http://dev.mysql.com/doc/refman/5.5/en/windows-upgrading.html I also adjusted the Datadir. But after the upgrade, ...
0
votes
1answer
49 views

Join on with modified ON

I am trying to create table with summary of few other tables. All solutions i came up with are very slow and clearly not optimal. Initially I tried with multitude of subquerries but that was very ...
1
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0answers
30 views

table scheme definiation it this way that insert duplicate into another table

I have a table in which there is a column name with SP varchar(10) NOT NULL. I want that column always to be unique so i created unique index on that column . My table schema as follows : CREATE ...
1
vote
1answer
2k views

Upgrading MySQL 5.1 to 5.5 on Centos 6 without removing dependencies

I'm trying to upgrade MySQL 5.1 to 5.5 using yum/rpm combo (yum to remove MySQL 5.1 and rpm to install MySQL 5.5). Most instructions I've found suggest to do first: yum remove mysql mysql-server ...
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0answers
347 views

Incorrect information in .frm file after a power outage?

CentOS release 6.3 (Final) x86_64 mysql Ver 14.14 Distrib 5.5.31, for Linux (x86_64) using readline 5.1 SHOW SLAVE STATUS\G: Slave_IO_Running: Yes Slave_SQL_Running: No ...
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0answers
427 views

MySQL InnoDB slow inserts

I'm currently struggling with an MySQL Community Server 5.5.27 when inserting large numbers of rows into a table. We're running a 24 core Intel Xeon machine with an SSD software raid array. I did some ...
4
votes
2answers
1k views

Does a TRIGGER improve the performance?

I understand that TRIGGERs are useful, as they take care of subsequent queries, but do they have an advantage from performance point of view too? Replacing two or three queries as INSERT INTO table1 ...