MySQL : Open-Source, Relational Database Management System

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Mariadb on Centos 7 not changing max connections based on my.cnf

The following configuration in my.cnf is not being followed. Max_connections go back to 151. please help as i have 16gb of dedicated ram that i would like to use properly. [mysqld] ...
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1answer
414 views

Does MySQL load the entire row into memory, or just the columns used in WHERE, ORDER BY and GROUP BY?

I have a table that isn't very large row wise (in the 100ks range), but that contains a lot of raw data that is very large in size. Despite having a relatively little number of rows, it's around ...
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1answer
36 views

Speed up MariaDB?

I have a Wordpress Woocommerce store using WP All Import Pro to run automatic imports on a 15 minute cronjob schedule. It's usually trying to update 400 to 500 items from our supplier every 15 ...
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3 views

Switching from MySQL to MariaDB resulted in a high number of transactions

I switched from MySQL 5.5.44 to MariaDB 10.0 on a server and the number of transactions went through the roof without any increase in website traffic(the website traffic is the only thing that uses ...
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1answer
158 views
+50

How do you calculate how much hardware resources you need for a database?

We are in the process of scaling our database servers. I was wondering how should we calculate how much hardware resources we need for our databases? Here is a little bit information about our ...
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2 views

MariaDB: Querying a timestamp partition

I'm having difficulties getting my queries to make use of the partitions when I'm selecting. They need to be able to do > sometime > sometime and between sometime and anothertime. However, if I ...
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9 views

Can't bring up second MySQL Galera node - 2015-08-27 21:53:13 32140 [ERROR] WSREP: Failed to read 'ready <addr>'

I am trying to migrate from MySQL m/m replication to MySQL Galera. After successfully installing MySQL Galera on node no. 3, I configured it as the first node in the cluster and have imported the ...
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1answer
139 views

mysql upgrading from 5.1 --> 5.6 do I have to do mysqldump before upgrade?

I was reading this document: http://dev.mysql.com/doc/refman/5.5/en/upgrading-from-previous-series.html It says when upgrading from mysql 5.1 to do a mysqldump and then a reload. Is there anyway ...
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4answers
297 views

How to exclude NULL values inside CONCAT MySQL?

If I have this - tadd is the Address table: CONCAT(tadd.street_number, ' ', tadd.street_name,', ', tadd.apt_number,', ', tadd.city,', ', ...
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2answers
209 views

Java Spring application Database triggers auditing - how to provide the right user that made the change

We are developing a new web application. one of the most basic requirement is to audit all entities changes into a separate table. We would like to use DB triggers for that purpose. We use MySQL as ...
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1answer
46 views

Matching data in two tables

I'm teaching myself SQL and I ran into a question that may be related to joining tables. I'm just a bit unsure. Say, you had two tables, one listing a customer's creditcard_number, and one listing ...
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1answer
54 views

Optimised way to search over 2 milllion poi data in mysql

We have over 2 million poi data in our mysql db. At any time we need to find what is the nearest point based on the following formula found at this link http://sqlfiddle.com/#!2/abba1/4 select *, ( ...
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1answer
12 views

MySQL get previous record and compare

Need to make a Comparable between the records of this table and take the total times the value calledstationid 42 preceded the value 34 (this is a system log table and calledstationid is not an ...
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1answer
215 views

Accuracy of mysqldbcompare vs other tools like pt-table-checksum

I was curious to hear what everyone's experiences are with using mysqldbcompare vs pt-table-checksum( from Percona Toolkit ) to find the differences between two MySQL databases. I have heard that ...
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2answers
66 views

Slow SQL query with LEFT JOIN

What my query is doing: I have two SQL tables and I want to copy datarows from the one table to the other table. I am doing this for statistics. The source table includes all current ...
2
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1answer
376 views

InnoDB forum DB design and Composite Primary Key (Cluster Primary Key)

I am designing forum database using InnoDB and got few questions , Could any one please help me to clarify them? Posts and Comments table design below CREATE TABLE `my_posts` ( `forum_id` ...
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2answers
39 views

Users vs. People - where to keep the email address?

I'm designing an app similar to Facebook, called Headtome. I want to have users that create public profiles, including email addresses. Then, Mary can choose to message John, and that message goes ...
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3 views

How to preseve Execute permissions for MySQL procedure with alter procedure (Drop/Create)

In MySQL you can not alter procedure rather you have to perform drop/create procedure to alter the body of the procedure. The problem is doing drop/create also removes the execute permissions given on ...
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2answers
56 views

Select highest id of each type in mysql

I am creating a database that keeps track of backups on our various servers. The query that I am using actually seems to work for the most part. The only issue is that it isn't getting the highest ...
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1answer
30 views

selecting same column twice for different value

I have a table like this; event_id pair versus score 1 1 11 100 1 1 12 0 ... 1 11 1 0 1 12 1 50 Now I want to ...
0
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1answer
25 views

Fastest way to do bulk import in MYSQL

I have got a question about the fastest way to copy a large number of records (around 10 million) from 1 table to another in MySQL. The target table has 1 primary key, 4 indexes and 3 foreign key ...
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0answers
7 views

MySQL - include a default value in LOAD XML INFILE statement

I have the follwing table: CREATE TABLE `tab1` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `DEFAULT` VARCHAR(25) DEFAULT NULL, `ITEM` varchar(25) DEFAULT NULL, `TIMESTAMP` TIMESTAMP ...
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1answer
33 views

How to improve this query so it'll run quicker

I've got this query: SELECT m.vlanID, v.vlan_name, m.interfaceName, count(m.macAddress) as mac, n.nd_name, p.interfaceDescription, p.interfacePortType FROM macs m, network_devices n, ...
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5 views

MySQL/Percona Audit Log Plugin Not Working

I've been looking to implemement the Percona Audit Log plugin. So far I have installed it and configured it, and it seems to be working ok. Except, I have installed it on a slave Database as I don't ...
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1answer
33 views

How to recover deleted records by mistake in Mysql

I am using Mysql.And by mistake I deleted very important info.Is there a way to recover or even to see the deleted info over a month ago?
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54 views

How to know which user update/insert or delete in MYSQL database?

Using the triggers I could make the establishment of a historic recordings in MYSQL tables where i detect all changes in my database. My problem is that I want to know which user made ​​the change in ...
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16 views

Line terminators \r and \n

As i am working on this project i have couple of questions about line terminators and how to know which one to use when. 1) when i load data into two tables using just "\r", all desired data is ...
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when I am executing this sql query it is taking 3 min time so i want to reduce that [on hold]

SELECT p.NAME AS Commodity ,COALESCE(allocation.alloted_qty, 0.000) AS Allocated ,COALESCE(inward.inward_quantity, 0.000) AS Issued ,sales.quantity AS Sold ...
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1answer
1k views

How can I get Performance Statistics to work in MySQL Workbench?

I have a complex query that is performing in subsecond time on my laptop, while the same query takes 70 seconds on my production server under no load against an identical schema. The EXPLAIN plan is ...
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Waiting for table level lock on wordpress site

We are experiencing issues with mySQL loading 100% of the server's CPU. While checking the running processes we found many of the following: Waiting for table level lock | SELECT option_name, ...
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0answers
20 views

Deleting large amounts of cascading records with minimal locking

I'm looking for a strategy to purge large amounts of logically deleted data from a MySQL database. The deleted records are in a relatively small table, but are referred to with many ON DELETE CASACDE ...
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7 views

Is it possible to cascade delete a column value? [duplicate]

So say I delete catID from table A and table B has the same foreign key value? It's hard to explain so I'll try and show you with the two images below: items table Is it possible to delete the ...
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1answer
396 views

Mysql foreign key cascade delete

Does mysql have a way to delete all sub links if a row was deleted from a "parent" table? Example table setup is below, the issue I am trying to avoid is having to maintain a script that deletes the ...
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2answers
31 views

What storage engine do I need - Mysql?

I have designed a database and came to the point of actually deciding which storage engine is better for my case. I estimate that during the first few years I would have around 100,000 - 500,000 ...
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2answers
34 views

Setting up MySQL master-slave replication

I am trying to setup master-slave replication on MySQL 5.6. When I update my database in the master, the change is not reflected on the slave. When I show the process list on the slave it shows this ...
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0answers
12 views

fast execution analitycs database with thousand rows to displaying in php [migrated]

i've table with a thousand rows and i want to creating analitycs with chart display my front end php my table structure is and how i display this data : by user_agent column i display operating ...
0
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1answer
21 views

Slow query - just error count

I deal with slow queries in whole project. I indexed heavily but the results are nowhere. I had a lot of logs (thousands per minute) from SCADA systems and I am trying to count them for each SCADA ...
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2answers
28 views

Disaster recovery solution for MySQL

I have set a Master-master replication with the second Master running as read-only. This master-master setup is on the same location. Now I will have to setup an DR for this production at a different ...
0
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1answer
12 views

Fulltext Search Doesn't Match a Hashtag

We maintain a table that looks like this to perform search queries on our forums database. I'll draw your attention to the FULLTEXT columns: CREATE TABLE `forums_posts_search` ( `post_id` ...
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4answers
24 views

Anyway to identify mysql slaves have read upto which binary logs

I have multiple slaves reading from one master.. But few of them are keep disconnecting due to network issue. Is there any way that i can make sure before setting up the bin log purging script on ...
1
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1answer
1k views

MySQL service stops after trying to grant privileges to a user

I am using MySQL 5.6, I was trying to create a super user for specific database but I got ERROR 1396 (HY000): Operation CREATE USER failed for 'superuser'@'%' Then I thought maybe there is already ...
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2answers
1k views

How much data is needed to show MySQL Cluster's performance scaling vs. InnoDB

I am evaluating MySQL Cluster as a possible replacement for an InnoDB schema. So far, I have tested it with 10s of MB of data, and found MySQL Cluster slower than InnoDB; however, I have been told ...
5
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3answers
1k views

Insert Speeds for large batches

In my application, my INSERTs seem to be taking a major chunk of the time. I have a large number of objects in memory (~40-50,000) which i want to insert into a table. Lets take a sample table ...
3
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1answer
3k views

MySQL: Lock wait timeout exceeded

I have a developer that has been trying to alter a large table (~60M rows). Via LiquidBase/JDBC they're running ALTER TABLE foo DROP FOREIGN KEY fk_foo_1; Today while it was running I checked in ...
0
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1answer
108 views

Mysql - unknown variable 'table_cache=64'

I use Mamp Pro 3. I upgraded Mamp's MySql to 5.6.24 using this script https://gist.github.com/tobi-pb/b9426db51f262d88515c. After that I ran the Mamp Pro and MySql cannot be started. So I looked the ...
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0answers
23 views

How to view the data from a .mysql file?

I have a .mysql database file. I need to open it and view the data. I've MySQL Server & MySQL Workbench installed into my Ubuntu 14.04. Now how do I open the .mysql file and view the data inside ...
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2answers
51 views

Remove duplicates from multiple joins

I'm using WordPress $wpdb->get_results for this query (it is simplified for question purposes): SELECT customer.id, customer.name, address.address appt.appointment_date, pay.date FROM customers ...
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2answers
115 views

Implementing versioning system with MySQL

I know this has been asked here and here, but I have the same idea with a different possible implementation and I need some help. Initially I had my blogstories table with this structure: | Column ...
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5answers
49k views

Matching single column against multiple values without self-joining table in MySQL

We have a table that we use to store answers to questions. We need to be able to find users that have certain answers to particular questions. So, if our table consists of the following data: user_id ...
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1answer
15 views

MySQL queries taking very long/not finishing

I just started working with databases and have a problem with queries taking very long. My table has the following form CREATE TABLE table (column1 INT(10) AUTO_INCREMENT PRIMARY KEY, column2 ...