All versions of MySQL (not Microsoft SQL Server). Please also add a version-specific tag like mysql-5.7 if that is relevant to the question.

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2
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988 views

Index usage for database server

How can i fix the Index usage on one of our database server? It says from our Nagios control panel that: Service: DB Index Usage Host: MySQL Cluster Address: ( our IP ) State: CRITICAL Additional ...
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0answers
1k views

SQL query optimization in Prestashop e-Commerce solution

I'm working on a layered navigation module within Prestashop e-Commerce solution. I'm trying to optimize a SQL query which creates a temp table during execution. I think this is creating a ...
2
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0answers
103 views

Can't connect to MySQL Cluster Storage (data) nodes

I've deployed a MySQL Cluster with a few nodes, and I want to access the storage nodes directly from another machine using NDBAPI. When I tried to connect from the same host it worked, but when I try ...
1
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0answers
14 views

Wildcard in CREATE grant in MySQL

MySQL allows the use of wildcards for database names, in order to allow an user to operate only on a subset of databases: GRANT ALL PRIVILEGES ON `foobar%`.* TO 'user'@'%' IDENTIFIED BY ...
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0answers
13 views

MySQL Error 111 caused by remote connection

This database has been running for years, such that all connections have came from the localhost address. Recently, I have been using xampp to develop new software, and have been connecting to the ...
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0answers
23 views

import TSV file into mysql table with SET datatype column

Is it possible to use LOAD DATA INFILE to load data into a mysql/mariadb table, where one column uses the SET datatype? If so, how do I specify the separator for the individual set elements?
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0answers
29 views

Access denied when trying to use Mysqlimport Utility (using Root Credentials)

We are trying to import large CSV files through Mysqlimport as described in This & This article. But even though I am using root credentials I keep getting the following error: mysqlimport: ...
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0answers
27 views

Groupwise max then join

I have a votes table that has many subitems. I have a subitems action table that records what action was performed by which user on which group, on which subitem, on which vote Users can either ...
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0answers
27 views

What is the maximum value for the index_length of a MySQL 5.5 table?

I'm trying to find out why a series of inserts is painfully slow (1 minute 15 seconds, on average) on a dedicated MySQL 5.5.47 server, while the same inserts are normally fast (less than 5 seconds) on ...
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29 views

Redis along with Mysql

I'm currently working on a mobile app alike Google Maps or Wave, but also including parking. The application its running with MySQL primarily. With at this stage most of our data is loaded by python ...
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0answers
53 views

mysql replication takes 6 seconds

I am struggling trying to understand why MySQL 5.7.11 semi-sync replication using RBR takes around 6 seconds between 2 VMs on the same physical host. I have verified the network bandwidth b/w the 2 ...
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0answers
40 views

How can I partition records vertically across machines?

I recently asked two questions: (1) how to store and connect partial records in two or more machines, with the record halves correctly associated, and (2) how to determine the increase in time/space ...
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0answers
19 views

Point to MySQL Binary Logs

So we have two linux servers that have a shared backup folder. The one server that is doing all the backups is working perfectly fine and has point in time recovery set up, which requires binary log ...
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0answers
24 views

MYSQL Created_tmp_disk_tables value increases on almost every query

Should I be concerned that tmp_disk_table # is growing even when I run a simple query like elect id from table with 1000 rows where id is an integer and is primary key) I've fiddled with other ...
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0answers
45 views

How can I migrate a WordPress site from MySQL to SQL Server Express?

I have developed a web portal in WordPress using xampp server. I have my database in MySQL. Now I need to deploy this WordPress portal on other system with SQL Server Express Edition. So how can I ...
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0answers
29 views

Missing DDL and table

I encounter the following errors after reinstalling MySQL Server. These seem to affect only one out of the several tables in the schema. The following errors are generated from MySQL Workbench. When ...
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36 views

MySQL Event scheduler not generating CSV

The scheduler seems to be running from INFORMATION_SCHEMA.EVENTS but there is no CSV output. The event scheduler has to automatically produce a csv to pass on the data to another system. It's like ...
1
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0answers
28 views

Using Galera-Replication, what's the use in having a GTID associated with your backup?

On the topic of using a backupscripts the documentation for galera-cluster states that: You can use backups of this kind to recover data, but they are insufficient for use in recovering nodes to ...
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0answers
40 views

Database has thousands of randomly named tables

Preface: First of all excuse me for bringing forwarding this weird question, as it could be just me. Situation: We have a Centos 6.5 Cloud VPS hosting our website, running MySQL 5.1 and it is also ...
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0answers
35 views

MySQL Slows Down after MYD file reaches 2GB (64 Bit OS)

MySQL seems to be writing rows OK (75,000 rows/min) until when the MYD file reaches 1.8 GB, and then the insert rate drops immensly (10,000 rows/min), and 1 hour later it's even slower (6k rows /min). ...
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30 views

use IFNULL in laravel

I have a query in laravel which is working fine. $subjects = $app->db->table('subjects')->LeftJoin('downloads', 'subjects.subjectID', '=', 'downloads.subject_id') ...
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0answers
56 views

Haproxy + Mysql Lost connection to MySQL server during query

I have setup a master-slave replication and added a haproxy before them. #HA-Proxy version 1.4.24 global log /dev/log local0 log /dev/log local1 notice chroot /var/lib/haproxy ...
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0answers
19 views

Trouble getting automysqlbackup to keep connection to MySQL server

I am trying to follow the instructions from the following page to set up backups for mysql. https://www.howtoforge.com/tutorial/mysql-incremental-backup-point-in-time-recovery/ However, once I get ...
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0answers
26 views

Visualize the effects of a cascading delete or update?

In MySQL, I'm working with a database that has integrity constraints on foreign keys (nothing overly special here). Is there a method to somehow visualize the effects of a cascading delete or update? ...
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0answers
24 views

When are UPDATE / INSERT operations processed in Online DDL in MySQL 5.6?

MySQL 5.6 includes functionality called Online DDL which allows ALTER operations to proceed on tables without applying a LOCK to the table (technically referred to as allowing Concurrent DML). ...
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241 views

Negative InnoDB Write Log efficiency in mysqltuner.pl results

I noticed something strange in results from mysqltuner.pl. I see this in mysqltuner output from three of my four servers with MariaDB 10.1.12: [OK] You have the latest version of ...
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0answers
23 views

MySQL master to slave dump fails when done over SSH pipe

When we need to [re]build a MySQL-5.5 slave, our usual approach is this (CHANGE MASTER TO / START SLAVE omitted for clarity): master$ mysqldump -uroot -p --all-databases --master-data > dump.sql ...
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0answers
19 views

Clustered index on last_update_at timestamp

I have a Votes table , which can be considered a wrapper. I have a sub_items table, which holds one votable item. One Vote has many sub_items. On sub_item is owned by only one Vote. I have a ...
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0answers
27 views

How to improve on this database design

I have different 'modules' . Currently , they are: Votes Chats To-do lists I am using mysql and long polling to get updates about these modules in near real time. I have also have a table called ...
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0answers
22 views

Changing tx_isolation and binlog format on master server - do i also need to adjust slave?

We are running a Drupal Commerce site with MariaDB 10.0 and master/slave replication. Because of the way our application works, we end up running in to a ton of deadlocks under heavy load. Apparently ...
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0answers
28 views

Joining and combining MySQL tables from Informix

I previously asked this in StackOverflow, But I couldn't find a solution, so I thought I'd share my problem here too. I have an old system that uses Informix for data storage, and I'm working on ...
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0answers
56 views

Database design in MySQL workbench

After doing some change As Mr Vérace told me here in this question, by changing the id names of each table into table_name_id and using the singular notation, I still need your opinion about this ...
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0answers
30 views

how to edit kvp data as crosstab/pivot

I am keeping data in key/value pairs. I know how to convert that data into crosstab form using queries like this: <!-- language: lang-sql --> SELECT master.tag, MAX(CASE WHEN data.key = ...
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0answers
33 views

AWS RDS: Running db dumps in to the server really slow

I am migrating data from out servers to AWS (from MySQL to Aurora) and inesrting the data is terribly slow. Is there a way to speed things up? Right now I'm creating gzipped dump files on our server ...
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0answers
76 views

Very slow MySQL performance

I have 4 million rows in MySQL. I have a count query to fetch from DB to Apache web server. The issue is first load (Count query) - when I click fetch button, it takes more than 5 mins. Second time ...
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0answers
59 views

Storing and searching user location using latest MySQL 5.7 spatial features

I want to use MySQL spatial features to store user location. I have read about MySQL spatial geometry data type. According to this article this works very well in MySQL 5.7 ...
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0answers
39 views

Combining multiple queries(select, update) (mysql)

I am making a project to challange myself doing complex script(despite my skills are not that high). All the things were good untill now. I faced an issue(lack of knowedge) for doing the following: ...
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0answers
52 views

Cardinality of an index in a MySQL table is equal to table's row size

I have just included an index to a MyISAM table and the cardinality appears to be 1 million something which is exactly the number of rows in the table. In fact it needed to be 315 because distinct ...
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0answers
92 views

MySQL 5.6 Performance Tuning Issue

I have read and try lots of things about MySQL optimization and tuning. I tried most of them one by one according to our needs but nearly I got nothing. I am doing my test using some simulation ...
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0answers
31 views

Ways to recover a corrupted Wordpress database?

As a result of increasing PHP_Memory Limit our wordpress data base has apparently crashed and been corrupted. Our host, Rackspace, attempted crash recovery but all attempts failed. What commands or ...
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0answers
28 views

implement geo / spatial / proximity search with php and mysql — what have you done successfully

For my website's users, I want to implement a worldwide geo / spatial / proximity search with php and mysql. I want to do this as simply and minimally as possible. What is the minimum data I should ...
1
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0answers
60 views

how to force MySQL unsafe replication warnings to throw an error

I understand that MySQL WARNING statements, with respect to replication unsafe statements, are not 100% valid. That is, if you know what you are doing, if you understand the schema, there are indeed ...
1
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0answers
42 views

Mysql slow copying to tmp table to indexing

I try to indexing table. The table size is about 60GB. But indexing query is hang on 'copying to tmp table' 18 hours. I found advice setting 'myisam_sort_buffer_size' myisam_sort_buffer_size : 128M ...
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0answers
101 views

What is a good database design approach for my Online Quiz Android Application?

I have been working on an Android Online Quiz Application with PHP & MySQL. I know what attributes i need however when designing the relationship it becomes complex and confusing when I analysed ...
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0answers
40 views

Fetch items where related rows has different values

I have table in MySQL called attributes, and other table, attribute_values, one attribute can have multiple values, values identified by context attribute and has value_c attribute wich contain value. ...
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0answers
49 views

Finding Duplicate URLs

The following URL varchar(2000) row holds URL values in a 3rd party database that I'm accessing directly, i.e. going around the HTTP API. MySQL [database]> desc TABLE; ...
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0answers
50 views

Connecting PhpMyAdmin to two different MySQL instances on the same host

I currently have running two MySQL instances on my machine, production and development - I can connect to each one using the following: mysql --host=127.0.0.1 --port=3306 -u root -p mysql ...
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0answers
27 views

pt-table-sync fails “Turning off AutoCommit”

While trying to use pt-table-sync with the following options for a list of slaves: pt-table-sync --print --replicate schema.checksum_table --sync-to-master slave-001 I receive the following error ...
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0answers
31 views

How to sync incomplete replication records in MySQL

if replication breaks and you end up with a couple of records not pushed out to the slave, is there a way to update the slave without stopping locks on the master and manually transferring a new ...
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0answers
27 views

Classic vs. GTID replication MySQL 5.6 - how to identity which one used from errors?

Is that true? In classic replication (SQL_SLAVE_SKIP_COUNTER=1) you never see UUIDs in logs and show slave status like 3e11fa47-71ca-11e1-9e33-c80aa9429562:1-5? When you see an UUID, there is GTID ...