MySQL : Open-Source, Relational Database Management System

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How to analyse innodb status on deadlock in insert Query?

I have a dead lock which i have posted here. I managed to get the innodb status from my server. Here is the Innodb status. OS WAIT ARRAY INFO: reservation count 247864, signal count 247470 Mutex ...
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Creating dump file with use command

I am taking backup of 2 tables from different schema. I need to create the "use dbname" statement at the beginning of each table. mysqldump --databases company --tables loadme --databases new_company ...
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Similar function NOWAIT in MySQL

Select for update nowait doesn't work in MySQL 5x (innodb). Is there any function like NOWAIT in MySQL?
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Is there a way to get slow-query-log-like profiling information on a single query?

Specifically, I'm looking for this information: # Query_time: 0.011922 Lock_time: 0.000088 Rows_sent: 107 Rows_examined: 663 Rows_affected: 0 Rows_read: 107 # Bytes_sent: 4152 Tmp_tables: 3 ...
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MySQL - SELECT INTO OUTFILE, with a UNION

Is it possible to issue multiple select queries whose resultsets are combined via union, into the same outfile? What I am trying to do, but not working: (SELECT email FROM table WHERE createdate ...
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Restore data from remote server using “.sql” file

I have a ".SQL" file which contains data at a remote server. I could download that file to my local machine and import data in my local DB, but because of network issues, and the size of ".sql" file ...
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MySQL flush logs, unknown error

I gave been trying to solve this for few days now, and cant seem to figure this out. I have been trying to set log rotation for mysql slow using linux logrotate feature, and my script seems to get ...
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MySQL Database and Table Loss

I have installed mysql and XAMPP on my system. I wanted to remove the mysql service of XAMPP. After removing it, I tried to install the new service for mysql using "MySQLInstanceConfig.exe". but now I ...
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How to keep one query from slowing down entire database?

Using MySQL 5.0.x, we have a process to generate benchmarks for our business that consolidates a bunch of data, then pull out data based on certain criteria. This process used to take 18 hours, it's ...
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Too much IO to MySQL InnoDB log files

I am using MySQL version: 5.5.38 I have dedicated HDD to InnoDB log files using innodb-log-group-home-dir option. atopsar -d 30 shows big load (>50%) to this HDD The thing is that I have only 75 ...
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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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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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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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627 views

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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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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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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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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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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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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Grant access to a table to all users

Is it possible to assign a grant to a table for all users, or a default permission so that when new users are created they will have the specific grants for that table to SELECT, UPDATE, INSERT and ...
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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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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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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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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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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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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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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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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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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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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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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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MySQL Locks while CREATE TABLE AS SELECT

I am running the following (dummy) query CREATE TABLE large_temp_table AS SELECT a.*, b.*, c.* FROM a LEFT JOIN b ON a.foo = b.foo LEFT JOIN c ON a.bar = c.bar Suppose the query ...
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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 ...