MySQL : Open-Source, Relational Database Management System

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How can you monitor if MySQL binlog files get corrupted?

I was wondering if there was any nice way to continuously monitor mysql master binlog files and detect if get corrupted.
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Db design for a quiz with variable number of answer choices, and each worth different score in a different category?

I'm working on a question/answer project and having a hard time coming up with a suitable database structure. Each question can have from 1 - "n" answers, and each answer is associated with one of ...
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Query to find and replace text in all tables and fields of a mysql db

I need to run a query to find and replace some text in all tables of a mysql database. I found this query, but it only looks for the text in the tbl_name table and just in the column field. update ...
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What to do when a field in a table approaches the max signed or unsigned 32 bit integer?

In any given database that hold user records in the form of an unique auto-increment field (for the sake of the example, inter-user messages)... what to do when the time comes and it approaches the ...
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1answer
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Order by column should have index or not?

I have added indexes to table which are used for searching result. I am showing results by ASC or DESC order. So that column should have index or not? I have 2 more indexes on that table. How ...
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Adding an index very slow…is there a mysql cmd to get an ETA or show progress?

I'm currently running an alter query on my table (20M entries) in order to add an index. it's running for more than 3 days already (stuck on 'copy to tmp table'). is there a way I can see the ...
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How to create a database for unknown kinds of data?

I am in the process of designing a database for a new PHP/MySql-based application. My problem is that I do not and cannot represent what should be saved in the database because it is unlimited and ...
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Deleting MySQL table with pending transactions

Is there a way to delete an InnoDB table or database with pending transactions in MySQL (preferably on file system level)? What happened: I use MySQL 5.5.28 and ran LOAD DATA INFILE… to import a ...
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Using Replication for Scale-Out

Having read Using Replication for Scale-Out, how can I route different queries to different servers, for example, SELECTI want to route to slaves and NON-SELECT to master. I assume as loadbalancer I ...
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How do I do a complex GROUP BY in MySQL?

I have a table that contains several keys into other tables (where each key is comprised of multiple columns). I would like to be able to group rows together that have an equal key, but I don't want ...
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Transaction speed benchmarks for mySQL v5.6 replication - seems very slow

I'm trying to select the best configuration for our new infrastructure but got a bit confused about the results. I used sysbench v0.5 for the tests: prepare data sysbench ...
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How to implement soft deletes?

What is your method of implementing soft deletes in a database? Ideally the solution would allow for decent performance on large tables take relationships into account take unique keys into account ...
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MySQL or Oracle Associate Certification?

I have 15+ years in software development and 7+ in web development, and I want to get a certification in another area, like DBA. I have 7+ years of experience like MySQL developer. Which is better for ...
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Using FORCE INDEX

I was in a presentation recently given by a Facebook MySQL engineer and he mentioned there that using FORCE INDEX reduces I/O. It was something to do with the MySQL Query Optimizer not needing to go ...
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Application Settings in Database

In the past I have stored all generic settings and configuration items such as: custom application title, home address, version, debug, etc.. all in a "settings.php" file that I would include into all ...
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How should I Optimize storage for this table?

I'm using MySql to store a basic table of this format: id int(11) //Auto-Incrementing ID data varchar(5120) //Random input data, compressed by a program, not mysql. ...
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Purpose of IDs in a User Table Database

In a table, such as a user table, where there will only be 1 row with a for any particular user, why have an ID field, let alone as the primary key?
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When to use MySQL query_cache?

Up until recently, I have viewed the query cache as a very important tool to improve query performance. Today, I was listening to a podcast that discussed tuning the query cache to 0, and using a ...
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Difference between count(*) and count(1) in mysql?

In MySql we can count the total number of records by using count(1) or count(*). Is there any technical difference between them?
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Why is LIKE more than 4x faster than MATCH…AGAINST on a FULLTEXT index in MySQL?

I'm not getting this. I've got a table with these indexes PRIMARY post_id INDEX topic_id FULLTEXT post_text Table has (only) 346 000 rows. I am trying to perform 2 queries. SELECT ...
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Is there a reason/benefit I am not aware of for this kind setup?

I now manage a MySQL database that was designed and created by another. I am confused about a certain setup that the original developer created.. He did not use auto increments for table IDs. ...
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how do I model this in database?

I am using mysql as my backend database. Here is the use case; A HolidayPackage is configured with some default offerings. These default offerings can be up/downgraded based on the options provided. ...
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Taking mysql dump from another machine

I have MySql db on Machine A , I have Mysql credentials. And accessing this MySQL from machine B which I have crdential's. But I couldn't take mysqldump from Machine B. Please help me. Both ae Linux ...
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Does the max_allowed_packet variable have any effect on LOAD LOCAL INFILE?

As the question states, what (if any) is the effect of max_allowed_packet on LOAD LOCAL INFILE? Does setting it to a large value load data files of large size such as 700MB into the db quickly?
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Will mysqldump command also backup all the views that are present in DB or there is a special command for it?

I am trying to backup my entire database along with the views. I am going to use mysqldump command. I was wondering if that will copy all the views or I will have to use separate command for it. ...
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Would it be sensible to create a MySQL user for each user account of a web application?

The thought occurred to me recently, but I have a suspicion the idea might be insane. A couple benefits I'm perceiving are: facilitate automated logging via triggers control mysql connections on a ...
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MySQL queries are 10 to 100 times slower after OS reboot

I have a MySQL server running on Ubuntu. If I restart the MySQL, everything is fine. If I however restart the OS, my queries take anywhere from 10 times to 100 times as long. The only "solution" to ...
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MySQL replication: 'Duplicated entry for PRIMARY key'

Could you please help me to understand why I'm receiving 'Duplicated entry for PRIMARY key' on a slave server after a full re-sync. Basically 'mysqldump' was running almost whole night and then the ...
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Index before or after bulk load using load infile?

I have a database with over 1B rows and two columns that are indexed (in addition to the PK). Is it better to have the index pre-defined in the table before the load infile or better to index after ...
4
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1answer
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MySQL on RDS, data transfer from one instance to another as a production job

I have a MySQL RDS instance ("production") from which I need to copy incremental data to another MySQL RDS instance ("reporting"). “Incremental data” being the new rows in certain tables. Currently ...
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1answer
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How much does table size affect performance?

Lets say I have a MyISAM table (amongst other tables) with 2938347 rows. This table is merely being used for logging and doesn't get emptied very often. By not regularly archiving or deleting these ...
4
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1answer
367 views

Hierarchical queries without CTEs

I'm new to MySQL. The GetFamilyTree(id) function that Rolando suggested in the Find highest level of a hierarchical field: with vs without CTEs question was great but when the id is greater than 999 ...
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1answer
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If MAX(id) != COUNT(id), does that mean rows have been deleted?

The question pretty much says it all. We're talking MySQL here, version 5.1. What I'm wondering is whether this would strictly means rows have been deleted, or if there are other possible scenarios ...
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Is it possible to encapsulate a table in MySQL?

I am new to Databases. I want the following: UPDATEs in a database to happen only through a stored procedure The user does not have GRANT UPDATE The user has GRANT EXECUTE ON PROCEDURE I tried it ...
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Is there a way to hint to query optimizer to MySQL which constraints should be done first?

This is my current query: SELECT BusinessID as ID, 111151.29341326*SQRT(pow(-6.186751-X(LatLong),2)+pow(106.772835-Y(LatLong),2)*0.98838574205337) AS Distance from ( SELECT * FROM ...
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Optimizing DELETE Query on MySQL MEMORY Table

I run a large forum which maintains a MySQL database for backend data storage. The 'session' table tracks logged in users & guests. It is currently about 100k records, so not really that large. ...
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MySQL replication: “Houston, We've Got a Problem”

I ran into a problem with our replication server. Essentially, we have 2 databases (database1 and database2). Master server has both. Slave has only database1. There is a Replicate_Do_DB: database1 ...
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1answer
857 views

Yum update mysql from 5.1 to 5.5

I was just in the process of 'yum updating' a server. One of the updates its suggesting to carry out is an upgrade from mysql 5.1 to 5.5. The mysql server operates in a master-master replication ...
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Multi-threaded replay of master activity for load/performance testing

Does anyone know of any existing tools/products that accomplish what I'm trying to do? After searching around for a bit the only thing I could find surrounding what I'm trying to accomplish is ...
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MySQL - Changing DB CHARACTER SET

I have a 30GB MySql DB, made of innoDB tables. currently the tables character set is: "utf8_unicode_ci" and I want to change it to "utf8_general_ci", what the best way to do it? currently i'm going ...
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How to convert mysql database charset to utf-8

I have a vb forum with a huge amount of data I need a way to convert this forum database tables charset with thier data from latin1_swedish_ci to utf8-general-ci How to do this ?
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1answer
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Strictly only RAM matters?

I have to work on a project which would have a extra large table with billions of records but only two fields one is id and another is text. And id would be set to BIGINT and PK then if 8+2 (extra 2 ...
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3answers
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Connecting to MySQL database from Analysis Services

I need to know whether it is possible or not to get data from a MySQL database and create a Cube in Analysis Services 2008. If so, tell me how to connect to MySQL Database from Analysis Services.
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Is tuning the innodb_buffer_pool_size important on Solaris ZFS?

We're running a moderate size (350GB) database with some fairly large tables (a few hundred million rows, 50GB) on a reasonably large server (2 x quad-core Xeons, 24GB RAM, 2.5" 10k disks in RAID10), ...
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1answer
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How do I make MySQL auto increment in random order?

I have a table that contains several keys into other tables (where each key is comprised of multiple columns). I would like to create a new column for each key that would be an integer such that ...
3
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1answer
558 views

How to migrate from MySQL to MariaDB or Percona with minimum downtime?

I want to migrate my MySQL 5.1 database to one of these databases: MariaDB, PerconaDB or MySQL 5.6 Is there any way to do this operation with no downtime or with minimum downtime possible? How? The ...
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Row size error with MySQL

I'm running a MySQL server on my Macbook (for testing). Version is 5.6.20 from Homebrew. I started running into "Row size too large" errors, and I've been able to reduce it down to this test case. ...
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1answer
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Determining what query was called

I want to reverse engineer what exactly happens to the MySQL database when a product is added in Magento. I will have to reproduce the query, because I would like to manually enter new records using a ...
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1answer
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mysql Wrong bytesec: 0-0-0 at linkstart: 0

I have several MySQL (MyISAM) tables that have been corrupted. Running CHECK TABLE mytable returns: > +-----------------+-------+----------+----------------------------------- | > ...
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Does a MyISAM table locks if I copy it while MySQL is running? (READ DISCLAIMER)

DISCLAIMER: I'm very aware this is not supposed to be done, but time consistency between tables aren't a concert here and Im trying whatever pops in my mind right now to have alternatives for ...