MySQL : Open-Source, Relational Database Management System

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How can I move a MySQL database from 5.1 to 5.6?

I have pretty big database, like with 5 000 000 rows in total. It is located in a remote server. I want to copy this database to my personal computer, for testing purposes. However I don't know the ...
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109 views

Retrieving row ranking in a table

I'm aware there are already many questions alike however none of those answers helped me achieve row rankings in a table. I have a table set up as so: ...
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582 views

Optimize MySQL query_cache_min_res_unit

My query cache settings are the following: mysql> SHOW GLOBAL STATUS LIKE 'Q%'; +-------------------------+----------+ | Variable_name | Value | +-------------------------+----------+ ...
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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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Increased query_cache_size, Queries slowed drastically on increased traffic

I increased our servers query_cache_size to 2gb, hoping for performance benefits. After sometime the query performance would drastically decrease. Once I dug in deeper, I found the queries in State ...
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How to autoincrement Prod_id based on Product_Name using trigger in mysql

Product_Details table : (Fields) Prod_id(Primary key), Product_Name, Prefix and Slno(Auto incremented) i need to increment Prod_Id based on the product name field and prefix field (Input will be ...
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232 views

mysqldump with automatically generated export name

When I do database dumps through MySQL WorkBench it picks a filename for me which is the current date (YYYMMDD). Now, I want to do this in a batch file since I want to make weekly dumps automatically ...
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2k 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 .
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MySQL : Extract SQL statements from binlog

I am trying the following command to extract SQL statements from binlog for using it in another database (Amazon RDS) mysqlbinlog /var/lib/mysql/binlog.000027 --start-position=54375264 ...
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472 views

MySQL Memory Grows Over Time

I've got a server running a LAMP stack with 1GB RAM that is maxed out on RAM usage. What I'm observing is that directly after a reboot, it drops to 25% usage, and then slowly climbs over time so that ...
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How to optimize MySQL for large BLOB updates

I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
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305 views

Information about Disk Storage MySQL

I am trying to create an application for monitoring MySQL,in my application there's a part of monitor DISK STORAGE, so after more research I have not found how to calculate : used and free size of ...
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121 views

Embedded select with rank

I am having the hardest time following the tutorials on this site regarding ranking with MySQL. I have a larger problem than others seem to show. My table is constantly updating with single answers ...
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314 views

replication breaks after upgrading master

I have a set up of replication with master 5.1.30 and slave 5.5.16 and the replication is working good Now i have upgraded mysql master to 5.1.47 As far as i know we have to turn off the log bin ...
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469 views

Do I need client certs for mysql ssl replication?

I'm setting up mysql replication using SSL, and have found two different guides. The first one creates both client and server certs, while the second one only creates server certs. I don't know ...
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1k views

How often does the slow_log table get updated in MySQL?

I've changed the long_query_time from 10 secs to 5 secs. I haven't seen any queries logged for a few hours now. Am I supposed to tweak my database for the slow_log table to gets updated more often? ...
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What to do with alerted variables phpMyAdmin for MySQL databases?

I've noticed the following alerted variables in phpMyAdmin Variable Value Description Aborted clients 5 The number of connections that were aborted because the client died without closing the ...
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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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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
8k views

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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6k views

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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4answers
729 views

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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6k views

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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1answer
2k views

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 ...
6
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1answer
493 views

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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260 views

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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4answers
503 views

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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234 views

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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679 views

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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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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690 views

TokuDB optimize table does not reclaim disk space

Was running an optimize table command against one of my tables about 11Gig in size, surprisingly used disk space grew by 2Gig immediately after optimization process finished. I would expect the ...
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2answers
8k views

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 ...
4
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2answers
1k views

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
4k views

Why does that query cause lock wait timeouts?

From time to time, I find a lot of these errors in my PHP error log: MYSQL.1213: Deadlock found when trying to get lock; try restarting transactionSQL The problem persists for about 2 or 3 minutes. ...
4
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1answer
2k views

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 ...
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371 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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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 ...