MySQL version 5.5 - please also tag with mysql for search purposes.

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How to log within a stored procedure that is encapsulated within a transaction

I have a stored procedure, let us call it sp_A which calls other stored procedures, let us call them sp_B and sp_C. For the sake of consistency an XA TRANSATCION is started within sp_A. What I ...
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1answer
593 views

Dedicated mysql server slow response [closed]

I have server in Kimsufi with 2gb RAM but my server is very slow , with simple hosting in ovh it responds quickly ... With pingdom.com test i have for server: 10 sec and simple hosting: 2sec is ...
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1answer
2k views

How to Reclaim Data Free in InnoDB Tables?

I came up with an idea on how to shrink ibdata1 in mysql database then i got this solution on stackoverflow STEP 01) MySQLDump all databases into a SQL text file (call it SQLData.sql) STEP 02) Drop ...
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1answer
229 views

Two MySQL requests at the same time - Performance issue [closed]

I have a MySQL server with many innodb tables. I have a background script that does A LOT a delete/insert with one request : it deletes many millions of rows from table 2, then insert many millions of ...
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881 views

What to do with unused RAM on a MySQL database server?

For years I have been running dedicated servers with more or less limited ressources, resulting in unsatisfying performance of the web application (Drupal). Tools like Matthew Montgomery's MySQL ...
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1answer
17 views

What should I do if i forget password in MySQL?

I am using MySQL5.5. I trying to login in mysql from terminal by using "sudo -u root -p" But i could not remember password. How can i fix this problem?
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2answers
531 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
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2answers
1k views

MySQL Community Edition Capacity

I am using MySQL Community Edition on Amazon RDS service. It is a very large database, 2/3 tables has about 10 millions records and 4-5 tables has 7-8 millions records. Questions How much capacity ...
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119 views

tables don't exist after unmounting and remounting external drive where database was installed

I want to create a database that's too big to keep on my own machine, so I'm trying to create one on an external hard drive. It works up until I unmount and remount the drive, at which point show ...
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2answers
628 views

MySQL user without SUPER privilege

This may be a simple question and may not be the right place to ask but I couldn't find any useful information from Google. Here is my question. When creating users in mysql using grant all ...
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1answer
52 views

ON DELETE CASCADE pseudo delete

For data integrity ON DELETE CASCADE is necessary but it's really dangerous when a delete affects like a Chain Reaction! I know one way to prevent this is to make a pseudo delete by putting a ...
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1answer
312 views

Select post and concatenating all categories it belongs to

I have 3 DB tables POSTS +----------+----------+----------+ | id | title | content | +----------+----------+----------+ CATEGORIES +----------+----------+ | id | title | ...
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4answers
351 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 ...
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1answer
2k views

Master-Master Replication Duplicate Key

I have set two servers master-master replication mysql , i manage to set successfully but the problem is the duplicate key i got MASTER 1 Configuration /etc/my.cnf [mysqld] server-id=1 bind-address ...
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1answer
167 views

want to download 3GB database table from my development mysql server [duplicate]

I need to download database structure with data. Total size of the DB is more than 3GB. If i use phpmyadmin it is not working. I have also tried by increasing the execution time in php.ini. I need ...
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1answer
680 views

Whether to use or not to use: DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

In one Database table, created_at & updated_at are defined as: `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP `updated_at` timestamp NOT NULL DEFAULT ...
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1answer
74 views

Query to retrieve data based on several where conditions ( Not off Topic , Answer provided below is right ) [closed]

Database : Mysql 5.5 i have a table T1 containing 4 columns : No. , Height , start_time , end_time In column height i have 3 distinct values only : Small Medium High Now i ...
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0answers
107 views

Refactoring IN Subquery, Avoiding Query in a Loop

I've got a table which was designed as both the current data set for participants, as well as being the historical changeset for those participants. This table has been in use for approximately three ...
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1answer
829 views

Is there a product to auto-build indexes based on slow queries?

I'm looking to either find, purchase, or write a script to identify slow queries, identify potential missing indexes, and when needed create the appropriate index within a reasonable amount of time of ...
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378 views

Create Drop Temporary Table very slow vs Truncate

I've got this stored Procedure that is called by an event that runs every 1 minute. The stored procedure selects some data from one device and puts it in a temporary table. Than it picks up other ...
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1answer
622 views

Unable to run update_mysql in MySQL 5.5

I have recently taken over managing a MySQL database running on Windows Server 2008 R2 . It is running 5.5.37 Community Edition. When it is started, it includes the following lines: Thread, Type, ...
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216 views

Upgrade from mysql 4.1 to mysql 5.5

I was going through upgrade process of mysql server. It is mentioned that to upgrade from 4.1 to 5.5 we need to upgrade step by step like first to 5.0,5.1 ...5.4 and then 5.5. I have some questions : ...
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21 views

MySQL slow query log not logging all slow queries [duplicate]

I am trying to analyze the hibernate query performance in our application. I tried logging all hibernate queries which take more than 100ms execution time from application side as well as using mysql ...
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1answer
43 views

MySQL database configuration for fastening the select and insert queries

There are several DBEngines are available for MySQL DB. Currently I'm using InnoDB. My actual problem is, I have a table that consist of millions of data. Therefore the select queries that given to ...
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2answers
2k views

Slow INSERT/UPDATE on InnoDB

I have a problem with the performance of my MySQL server, let me explain: I instaled a MySQL server, version 5.5.20 Server version: 5.5.20-log Source distribution SELECT queries runs fast on ...
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2answers
22 views

Joining on 3 different keys as they're set

I have these tables: TABLE vessels ID int PK organization_id int FK fleet_id int FK name VARCHAR TABLE settings ID int PK organization_id int NULL FK fleet_id int NULL FK vessel_id int NULL FK ...
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1answer
51 views

Will composite indexes or unique indexes help with query performance?

I need help with identifying indexes to increase performance of the following query. I'm currently using v5.5 with InnoDB. I cannot modify the query. However, I can add indexes as needed. The ...
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32 views

How can I determine the performance (rows/second) for a certain query on one of my tables?

I want to find the performance (rows/second) for an UPDATE query on one of my tables so I can adjust my WHERE clause to select an appropriate number of records. The table has around 10 million rows. ...
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1answer
193 views

Slow queries InnoDB occasionaly

I have the next table: CREATE TABLE `sessions` ( `session_id` char(32) COLLATE utf8_unicode_ci NOT NULL, `session_expires` int(11) NOT NULL DEFAULT '0', `session_data` varchar(10000) COLLATE ...
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1answer
74 views

How can I make multiple joins on the same table?

I have a table (signal) which contains references to two other tables (ee and eeav). I want to perform an SQL Query which combines the data from ee and eeav tables. The situation is as follows: The ...
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2answers
9k views

How to outer join multiple tables to retrieve uncommon records

I'm trying to do an outer join in MySQL to identify records not common to 3 tables. Here's my current effort http://sqlfiddle.com/#!2/02b92/30 I'm trying to retrieve the records not common to all ...
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1answer
31 views

Is it possible to find the user whose aggregated score reaches X value first?

Given this sample fiddle containing sales value and date for two users: http://sqlfiddle.com/#!2/8148be/3 How can I find the first user who has reached a total saleValue of 30 since the beginning of ...
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251 views

Is there a way to truncate the microseconds of a CSV value when importing data using LOAD DATA INFILE?

I'm loading data using LOAD DATA INFILE in 5.5 where the value includes microseconds. I must use DATETIME data type. Currently, I'm using regular expressions to remove them from the CSV prior to ...
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186 views

Buffer pool above 90% utilized causes MySQL to crash

Without getting deep into the architecture and setup, is it common behavior for MySQL to act in this manner? EDIT I'm using Rolando's script to identify how full the innodb_buffer_pool is. SELECT ...
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1answer
328 views

database design for dynamic menu bar [closed]

I am trying to create a menu bar which will load dynamically on user log in, based on the user roles. Say if the user is an admin he can see all the items listed under the header and if a user is a ...
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1answer
2k views

How to resolve “Error log file size is increasing in mysql 5.5” issue w/o restarting mysql

I have an Ubuntu server with MySQL 5.5 installed. In /var/lib/mysql a .err file is kept on updating with these warnings only: [Warning] IP address '234.22.11.221' could not be resolved: Temporary ...
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54 views

Will MySQL redirect a read request to the master after a certain time? [closed]

I can't find what variable controls this or any information about the time limit. Thanks!
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1answer
151 views

How to find the length of multiple column index in MySQL

Is there a way to find out what is the length in bytes for the unique index (NKU) key created through the following command: CREATE TABLE test_ ( testId bigint(20) NOT NULL, name varchar(75) ...
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2answers
4k views

MySQL COUNT Query taking too long time to execute

I have below query that takes 7 secs to run SELECT COUNT(*) AS `count` FROM `yuldi`.`businesses` AS `Business` LEFT JOIN `yuldi`.`businesses_categories` AS `BusinessesCategory` ON ...
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2answers
114 views

Are relay logs necessary for replication?

I'm trying to understand when/where using relay log is beneficial. According the documentation, mysql captures and writes events from the master's binary log as the result of the I/O thread. Then, the ...
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2answers
370 views

Nested query efficiency in MySQL

I have a table with several attributes like this: id id2 attribute -------------------------------- 1 100 blue 2 100 red 3 100 green 4 100 white 5 102 blue 6 102 green 7 102 ...
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1answer
31 views

Is there any value in adding an already indexed column to a composite index?

The title says it all. Does the query optimizer see composite indexes where each column is already indexed as redundant? Or, is it used when each of the composite index's columns are in the WHERE ...
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1answer
134 views

Migrating MyISAM tables from 5.5 => 5.6

I was wondering if anyone had any pointers on migrating MyIASM tables from mysql 5.5 to 5.6, specifically using Percona builds, via an rsync? Is this safe? I know we need to do a full ...
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50 views

How can I store least used table files to a slower drive?

Is it possible to separate the least used and most frequently used data files on to separate disks when using InnoDB?
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1answer
1k views

Mysql 5.5 InnoDB growing CPU - Going crazy

Good morning, I'm currently facing a problem where CPU usage keeps going up until the server crash. I've tried multiple best practices proposed in this forum and on Percona, reinstalled the server ...
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1answer
48 views

How to decipher the transaction message in innodb status log.

I have several transactions that seem have stalled. Looking at the innodb status log, I found several messages similar to the following: ---TRANSACTION 69DBBB, ACTIVE 947 sec starting index read, ...
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1answer
241 views

How to store temp tables in memory during table “optimize”?

When optimizing tables, SHOW PROCESSLIST lists it as "copying to tmp table". I'm trying to ensure the copy takes place in memory to speed up the process. I've tried adjusting the tmp_table_size to ...
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3answers
270 views

Will redirecting queries to dev/null warm up indexes?

I'm trying to warm up the buffer pool. Will running a query and re-directing the output to /dev/null suffice? e.g. mysql -u username -p -e "select id from tbl where 1=1" > /tmp/results.txt Thanks
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107 views

MYSQL: Join with many to many

I'm trying to create a view and trying to see what can be done, I have a main table a table I want to join to and also a junction table. Event table (it's very big so it's just dummy data): ...
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3answers
99 views

Mysql Master Offline

In a unidirectional Master-Slave setup, should the slave be manually stopped in cases where the Master is offline due to Maintenance, Crash etc. ? Or should one just leave it so that it keeps trying ...