MySQL : Open-Source, Relational Database Management System

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Write-lock a whole table during transaction

I need to perform a delicate operation to my table in which I will solely insert, delete and select upon all of my rows and no God may interfere with the table during this operation: the table will be ...
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Search functionality using joins

I have three tables as mentioned below. I need to implement a basic search functionality where user will search for a keyword which could either match 'title' (from Proposal table) or 'msNumber' or ...
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265 views

MYSQL Timezone support

We are having a shared hosting plan and they are saying that do provide MYSQL Timezone support in a shared hosting plan. I can create timezone related tables in our database and populate them with ...
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1answer
273 views

Mysql can't write to filesystem

I need to output some queries as csv files. The directory is in the webroot and I want it to be writable by apache too, so I'm trying to add mysql to the www-data group (on Ubuntu). I thought this ...
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377 views

optimizing MySQL for traffic analytics system

background : I've developed a URL shortener system like Bitly with same features , so the system also tracks clickers info and represent as graphs to the person who has shorten the link as ...
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2answers
203 views

MySQL incremental backups per database (not global)

While searching for free/open-source MySQL incremental backups solutions I have found a number of ways to do incremental backups and all of them seem to either rely on "logical" way of backups/restore ...
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100 views

Query to Access a specfic data in the row using python

Am using wordpress and phpmyadmin for handling my database Below is the code I use to view entries on my form using python. In the form I ask users to check/uncheck specific questions. It works as ...
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2answers
30 views

Mysql slow query log always include “# Time:”

I am trying to parse the mysql slow log with logstash so it's important that the format is consistent. I have noticed that if statements execute at the same time, the line # Time: yymmdd is only ...
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21 views

Use Create Trigger to create New table using calculated values from common groupid column values

I have a TABLE_A in Database1 the contains rows with a common group id. I am wanting to use the CREATE TRIGGER function to generate a new TABLE_B in the same Database1 that contains calculated values ...
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1k views

MySQL Workbench Cannot start SSH tunnel manager

I don't know why this error is happening when I try to connect by MySQL Workbench. Cannot start SSH tunnel manager. I'm using slackware 14.1 and installed all dependencies. I already installed the ...
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1answer
150 views

MySQL replication using a lot of IO

I'm having big troubles on a database pool I've setup recently. There is a master, and 4 slaves replicating one DB. All using MyISAM engine. Thing is, during the replication period (when the slave ...
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1answer
96 views

Randomizing the Auto Increment in Mysql

We have a database, where we insert data into table whenever we receive an order from our services. We use auto_increment to generate the ID and assign the order with the same. This is usually same ...
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50 views

Schema review for system to advertise cars

Ok, so I am carrying out a rather simple task as part of a job requiretement. Here is the task in a nutshell: Design a form for creating ad for selling car Form has 2 have: 2 drop downs: Car make ...
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1answer
650 views

Proper procedure for migrating a MySQL database to another Debian machine?

I have one server running an older Debian version with MySQL 5.x and a newer Debian server, also running MySQL. I've created a backup of all databases on the first server like so: mysqldump -uuser ...
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creating deadlock for distributed database in mysql-(Testing purpose)

I need to create a deadlock for distributed database in MySQL for testing purpose with a simple sql query(without front end), can anyone good with MySQL query help me out in this with sample query. ...
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1answer
219 views

MySQL is using wrong index

This is my table: - user_id INT (foreign key on `user` with the reference `id`) - question_id INT (foreign key on `question` with the reference `id`) - option_id INT (foreign key on `option` with the ...
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3answers
450 views

Finding differences between a master and slave when pt-table-sync fails

I have a table that's showing some differences on a master and slave according to pt-table-checksum (PTC). I've found some verifying differences beyond that. Certain tables in the mix have composite ...
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2answers
4k views

How to force higher values of open_files_limit or table_open_cache?

I'm having a frustrating problem where setting my.cnf to values higher than I currently have them does not 'take'. This is MySQL 5.6.14 on MacOS X 10.8.3 I'm trying to address dropped connections ...
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1answer
601 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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1answer
21 views

How to enable queries logs in MariaDB

I'm running mysql Ver 15.1 Distrib 5.5.42-MariaDB, for Linux (x86_64) using readline 5.1 in CentOS 6.6 server. I'm trying to get queries logging info and I'm doing by enabling log support at ...
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1answer
98 views

How to restore data after MySQL Upgrade?

I upgraded from MySQL 5.5 to 5.6 by uninstalling 5.5 and then installing MySQL 5.6. Now that MySQL 5.6 is running, none of my DBs or data is present/visible in MySQL Workbench. I also see that I ...
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96 views

custom product variant upload

I'm building a custom eCommerce solution for a client. I came up with this database design: +---------------+ +---------------+ | PRODUCTS |-----< SKUS | +---------------+ ...
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1answer
27 views

MySQL overhead of calling a Stored Procedure

Within Java, we access MySQL (v5.5.40) via JDBC -- a prepare statement, setting parameters then calling the stored procedure. It appears that every execute() has the overhead of 4 meta-calls (per ...
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1answer
748 views

Mysql Getting Access denied for user 'root'@'localhost' (using password: YES) constantly in log

I have MonYog running and it is monitoring my DB Server. It gives me constant alerts that the number of refused connections has exceeded the threshold etc. Looking in the LySQL.Log I can see constant ...
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1answer
69 views

Summing a column based on uniqueness of another column without using temporary table

I have a table like this: CREATE TABLE `files` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `hash` char(40) DEFAULT NULL, `size` bigint(20) unsigned DEFAULT '0', ...
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64 views

Selecting most recent date when dates are stored in another table

Working in a MySQL database, I have tables set up like this: Table song_instances has song_id (int), meeting_instance_id (int) The meeting_instances table has columns meeting_instance_id (int), ...
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278 views

How to repair all indexes in a MySQL database?

My database got corrupted, and now the php app is throwing this error: Invalid query: Can't find FULLTEXT index matching the column list The error is not very useful, since it doesn't say what ...
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2answers
5k views

How to sync two databases (alternative to mysql replication)?

Hello i have 2 mysql databases where most of the structure is constant except few tables (additions) in 2 dbs. I need to synchronize these 2 databases mainly common tables from one db to another. This ...
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1answer
244 views

MySql - is possible that performance issues are caused by dynamic SQL?

We have this MySQL SP, which uses dynamic SQL. It seems it does NOT perform well under load. It is possible that this SP becomes slow under load because it uses dynamic SQL? Can dynamic SQL cause ...
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73 views

Select only rows that equal x but not x and y?

I'm having quite the challenge with selecting hierarchical data in mysql although I feel the schema should be optimized for it since it's based on the wordpress database model. I've got 4 tables... ...
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1answer
1k views

MySQL : “FLUSH TABLES WITH READ LOCK” started automatically

I would like to understand how this happened. I was running a query that would take a long time, but should not lock up any table. However, my dbs were practically down - it seems like it was being ...
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2answers
1k views

Which one to use? InnoDB Replication or MySQL Cluster?

I am building a url shortener and I use InnoDB as the storage engine for link data. I will start with a single VPS containing both application instance and MySQL database instance on the same Virtual ...
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787 views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
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30 views

Very weird Innodb Corruption Issue

I'll try to keep this to the point. System: OPenVZ VPS, debian 6, 512 MB RAM, 50 GB HDD (25GB free) I have a mysqldump dump file (3GB), that was created when the innodb database was working fine. ...
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MySQL log shows excessive meta queries on SP calls [duplicate]

We access MySQL via JDBC -- a prepare statement, parameters binding then invoking the actual stored procedure. It appears that every execute() has an associated "overhead" of 4 meta-calls (per MySQL ...
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how to design Multilevel and multiuser application database schema [closed]

I am developing an event management application with the user roles like super admin, admin and user. I want to design database in the way that only superadmin can login and create admins of ...
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2answers
14 views

Structure database(s) dealing with different time points

I have few data sets that give a score for a specific account at a specific point in time. So, account A might have a different score each quarter going back 5 years so. There aren't a ton of data ...
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1answer
200 views

How can i import 150GB database after deleting ibdata1,logfile in MYSQL?

I have 150GB database and my ibdata1 file size is 240GB so i want shrink the ibdata1 file so for that i have to export the DB and then drop the tables and then stop mysql, delete the ibdata1 file and ...
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1k views

Are there any tools to go from ERD to DB design and vice versa? [closed]

I'm learning DB design and looking for some tools, preferably open source software, that could help go from an ERD to a DATABASE and vice versa. For the record, the database i'm using is MySQL.
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9 views

Database Importing Collation

Migrating from DB2 found this error message: Error message: Incorrect string value: '\xF2\xAC\x9F\xB0or...' for column 'column_name' This is when trying to import an XML to MySQL. I should have a ...
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1answer
173 views

MySQL 5.6 replication causes 'waiting for table lock'

All of the sudden queries on slave server stopped with status "Waiting for table level lock" I restart mysql service and stop replications and locking does not show up anymore. Once I turn ...
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1answer
37 views

Is there a performance hit for querying two different databases?

I have two tables, A and B, which are located in different databases on the same MySQL server. I would like to create a derived table C from tables A and B, as an inner join between the two tables. ...
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11 views

Insert in PXC Cluster are not equally distributed

I have another query with regards to pxc cluster i have 4 nodes in pxc cluster all nodes have the same cnf file and one server as haproxy. Config File Detail [mysqld] datadir=/var/lib/mysql ...
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1answer
16 views

Mysql's internal mysql database in replication

I searched around but the word game seems to delude any valid result and could not find anything relevant. Mysql (the RDBMS) has an internal database named mysql, this database has information about ...
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2answers
17 views

How to deny connections to localhost and force to use FQDN instead

I have a server running Apache and MySQL. Connections to MySQL work fine when using localhost in the connection settings. Now I'd like to force our developers to use a FQDN instead of localhost. This ...
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1answer
29 views

Speed up procedure

I was wondering if this procedure can be executed faster. There are indexes on the joins and where's. Depeding on the size of product_id_CSV it takes approx. 2.5 sec. CREATE ...
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1k views

ERROR 1166 (42000) at line 65203: Incorrect column name ''

I have a big snapshot database size is about 44GB in mydata.sql. When I run it overnight, it show this error message: $ mysql -u root < mydata.sql ERROR 1166 (42000) at line 65203: Incorrect ...
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2answers
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MySQL - SELECT on MyISAM Table on index - Does table size (rowcount) matter?

I was arguing with a coworker if SELECT * WHERE t BETWEEN ? AND ? on a MyIsam table where t is an index is significantly slower for huge tables. The hypothetically returned dataset is always the ...
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12 views

MariaDB/InnoDB: What to do on “Locks in Status-Log but no locked table found”

We migrated lately from MySQL to MariaDB. SELECT VERSION() 10.0.13-MariaDB-log When executing this: SHOW ENGINE INNODB STATUS I get (shortened): ... ---TRANSACTION 279257007, ACTIVE 23981 ...
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6 views

mysql dump import incredibly slow on my developer's machine

I have an SQL dump, it's pretty big (411 MB) and it took 10 minutes to import on server A, the same import on my workstation B has an estimate (pipeviewer) of 8 hours to import (it imported 31 MB in ...