MySQL : Open-Source, Relational Database Management System

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2
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1answer
293 views

Is this amount of disk IO expected with MySQL?

I am running MySQL 5.5.34 on an Amazon EC2 micro instance with EBS (elastic block storage). The instance has been running for around 10 days and according to Amazon I've accumulated around 8.5 ...
2
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1answer
25 views

How MySQL Queries and Questions status variables are calculated?

I have a mysql server running on 5.6.19 version and I got confused with the status variables Queries and Questions. show global status like 'Queries%'; | Queries | 28058738 | ...
0
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1answer
21 views

How to insert UNIQUE IDs values from several tables into events table

I have a table called events defined as follow: rep_id, hcp_id, brand_id, email_id and content_id is the IDs in other tables. event_type should be kind of array containing this values: [ ...
0
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1answer
142 views

MySQL data transfer to different schema

We have two servers: one for the developper (me) and one for the tester. While working on the app, I sometimes make little changes in tables's schemas. (Like a new field, or a field type) I'm trying ...
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13 views

Mysql command “SHOW DATABASES” returns invalid databases

I have a Mysql server with a number of databases on it - 16 if i'm not mistaken. When I run the SHOW DATABASES command i get 30 rows. I would have expected 17 rows. The 16 databases and ...
2
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2answers
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
243 views

How to duplicate related rows

Tables: Payments with auto-increment ID and one-to-many relationship to Projects such that one payment (say £10) has two records in Projects allocating the £10 between the projects. Now next month, ...
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0answers
14 views

Mysql Index Creation Internals

Right now there are two ways to build an index of a table in MySQL. Create the table structure first, then import the data and add indexes later. Create the table structure with indexes and then ...
-1
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1answer
34 views

Grouping based on the status, then count its product and the total based on its category ID [on hold]

I have a table with product ID, category ID and status of the product. +---------+-------------+-------------+ | id | cat_id | status | +---------+-------------+-------------+ | 1 ...
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0answers
24 views

MySQL bulk deletions

I am currently looking at how to most efficiently delete rows from a table in bulk. The database I'm using is MySQL with innodb. The table I want to delete from can be any size, but will usually be ...
0
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1answer
12 views

Cannot overwrite file: /var/lib/mysql/ibdata1 when using Percona xtrabackup

I am receiving an error when I am trying to restore from a percona backup to my local mysql server. Cannot overwrite file: /var/lib/mysql/ibdata1 at /usr/bin/innobackupex line 2128. sudo ...
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1answer
234 views

pt-table-checksum - Verify MySQL replication integrity

export/import: $ mysqldump -h6dhdbm01 -p clee2 users > 6dhdbm01-clee2.users.sql Enter password: $ echo $? 0 $ mysql clee2 < 6dhdbm01-clee2.users.sql $ echo $? 0 $ pt-table-checksum: $ ...
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1answer
194 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 ...
0
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1answer
121 views

MySQL Subquery Returns Null In Stored Procedure, Works Fine In Query

I have a subquery in a MySQL Stored Procedure where the value returns null even though the data is clearly there. Pulling the subquery out and running it works fine. I've checked the parameter values ...
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7 views

how to do a backup and restore for a single database with mysql enterprise backup

I am Chinese, the documentation of mysql enterprise backup is hard to understand for me, and now I need to finish my job quickly, I wonder is that possible to backup a single database and restore it ...
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2answers
2k views

Hyperthreading & MySQL InnoDB Thread Concurrency Performance

I have a dedicated DB Server with the following specs" Ubuntu 12.04 LTS Server Intel(R) Xeon(R) CPU X5670 @ 2.93GHz 12 Cores MySQL 5.5.29 64 GB RAM RAID10 We are currently doing Hyperthreading ...
0
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1answer
148 views

MySQL-How to find that value in a column is subset with all other values in same column multiple time

I have a table named as Team where table contain 3 column (ID,Team,Task). Its datatypes are (INT,VARCHAR(255),INT). Below you will find a sample table where I would like to perform the query on column ...
2
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1answer
54 views

How to check foreign keys related to a table

How to see foreign keys related to a table in MySql? Background : I wanted to drop a table in MySql which has a foreign key constraint. When I do it I get this: Error Code: 1217. Cannot delete or ...
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2answers
103 views

Recommendation for the mysqldump?

I have approx 90 GB of database, I need to schedule a mysqldump backup , thats why I Required a recommendation how much time it takes for the full hot backup? Because I didn't taken that much size of ...
0
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2answers
175 views

What's faster: two UPDATEs with WHERE (in / not in) or one UPDATE with CASE?

What's best performance wise, two separate UPDATEs: UPDATE table1 SET enabled = 0 WHERE code NOT IN ( SELECT id FROM table2 ); UPDATE table1 SET enabled = 1 WHERE ...
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0answers
12 views

hashed password retrieval in mysql

here I am again with the next question! I hash a password as follows: mysalt=os.urandom(12).encode('hex') passhash =mysalt + pw hash =str( pbkdf2_sha256.encrypt(passhash)) How can I verify this ...
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2answers
560 views

Can't get mysql running

After canceling an Ubuntu upgrade, Mysql refuses to start. this is what I get when I try to run it : $ mysql ERROR 2002 (HY000): Can't connect to local MySQL server through socket ...
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1answer
335 views

Syncronize mysql databases between local and hosted servers automatically

We have many website with Development , Staging and Production Server. we have many developers for many projects, we need a solution to synchronize the database with developer database with staging ...
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0answers
9 views

What could cause 300+ connections from a simple query in MySQL?

I am retrieving results from a table in MySQL 5.5. When I run even a basic query on this table hundreds of connections are shown in the Server Status screen in MySQL Workbench. Even for a simple query ...
0
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1answer
168 views

insert row if table is empty, else update row (mysql)

i have 2 tables "table1" and "table2" both have TIMESTAMP cols for starttime and endtime. i want something like if (table2 is empty) insert into table2 (table2.starttime, table2.endtime) value ...
0
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1answer
432 views

Strange Locking issues while playing back logs via percona playback

Problem while replaying logs I am in the process of benchmarking a new DB node (specs at the end) and have run across some strange behavior: As described here i: Created a dump (innobackupex ftw) ...
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5 views

Post categories model for a user submission wedbsite

I'm building an user submission site where users can make posts to content_types: Blog, Movies, Photos, Forums. Since these content types only have slight variances I would like to keep them in one ...
1
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2answers
581 views

Errors while creating multiple mysql-5.5 instances

I have installed 3rd mysql instance on my testing server. 2 instances already running without any issues. When I installed 3rd instance by mysql-5.5.30 zip source, it installed successfully but when ...
0
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1answer
3k views

How to perform a while loop on the query result

I created a trigger AFTER an UPDATE of a column in a MySQL database. When the trigger detects a certain value, it should perform some actions. This is what I have at the moment and is working fine. ...
0
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0answers
15 views

Filesort when using view

I am sorry for asking, but I can't figure what i am doing wrong and filesort appears in my explain. The id column that I use for sorting in the following examples is a primary key... If I create ...
0
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2answers
21 views

understanding mysqldump auto-backup performance issues and inner functionality

Is there a performance issue, if I run a cronjob in background with mysqldump --single-transaction with a 60 seconds interval? Will my original database keep functioning without an issue while the ...
2
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1answer
2k views

Extract MySQL information from a compressed tar.gz file

I have a back up-of a MySQL database which is contained in a .tar.gz file - I need to restore it. I've never had to do this before. The only way I can access the database is through phpmyadmin. There ...
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0answers
12 views

Working on a blog creation website; should I be creating a new table for each blog, or keep everything on the same table?

So I'm working on this blog creation website as a side project. I don't actually expect it to become anything, but I want to make it as efficient as possible, even if just for practice. The idea is ...
3
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2answers
190 views

Problem in Fetching Result set in Desired Format

I have 2 tables having the following columns Person ------ person_id, first_name, middle_name, last_name Items ----- person_item_id, person_id, item_type, status, ordered_date The query is ...
0
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1answer
161 views

Using non-replicated read/write databases on a MySQL slave server

I have a MySQL slave server that has two databases being replicated from a master. What I'd like to do is add a third database that I will exclude from replication and use as a read/write database. ...
0
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1answer
366 views

MyISAM : Should I be concerned by these warnings?

I restored some tables from recent Databases backups. Because Im supporting a legacy system that only uses MyISAM tables in their DBs, for backing up I used a little script that pretty much copies all ...
0
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1answer
599 views

ERROR 1226 (42000): User 'root' has exceeded the 'max_user_connections' resource (current value: -1)

I'm using mariadb and have error ERROR 1226 (42000): User 'root' has exceeded the 'max_user_connections' resource (current value: -1) I'm set max_connection to 1000 and not set max_user_connections ...
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+100

how to increase speed of this mysql query?

How I can increase speed of this search query? This search bring news based on time and title and text. each item has own factor. SELECT * , MATCH (`title`) AGAINST ('tax in work') * 1.65 AS ...
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2answers
42 views

insert into select with union needs derived table

Why do I need to do another select when I am trying to insert distinct values into a table? Also: is there a better way to do this? WORKS: INSERT INTO phppos_categories (name) SELECT category FROM ...
2
votes
1answer
734 views

SQL set profiling

I'm setting up an automatic database backup for a website. When I try to do a backup it comes up with the error" MySQL error: The 'SHOW PROFILE' feature is disabled; you need MySQL built with ...
0
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2answers
2k views

Mysql Server Login and Permission Deny Error

I have a problem with MySQL server. After upgrading MySQL server from 5.3 to 5.4, I am not able to log-in using my MySQL root password (Yes, I am able to log-in without password!). Also not able to ...
0
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1answer
59 views

Slow “CREATE TABLE” and “TRUNCATE” on MySQL / MariaDB

I am fighting with performance issues on a local MariaDB instance. Fun thing: I previously had problems with all my INSERT and UPDATE and DELETE queries. This got signigicantly faster (~40ms -> less ...
5
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3answers
2k views

MySQL Workbench Tabs refuse to close

I'm using MySQL Workbench 6.1.6, and I have opened a SQL Editor Window and have 14 Query tabs open. If I close the connection, and then open the connection again from the Home page it reopens all 14 ...
0
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0answers
15 views

Optimized ways for defragment mysql database table

We have a database in MySQL which has more than 500 GB of data, and currently in the process of purging data and count might go beyond 1 million. As we know that purging might lead to high ...
5
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1answer
337 views

Deadlock free MERGE-alike in MySQL?

I am trying to implement some parts of MERGE in the MySQL driver in Drupal. Of course, Drupal has something but in truth it only works because the most frequent MERGE issuer just eats exceptions. So, ...
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2answers
35 views

how to store mp3 files in mysql database by using phpmyadmin?

first of all i am new to database, but i want a database for my site to store mp3 files in it so later i play them on my site by using jplayer. little though i know about database they said there are ...
0
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1answer
282 views

How to automatically Reset Query Cache for improve table cache hit in MySQL?

I have a VPS running CentOS 6.4 and 2.5GB RAM, Intel(R) Xeon(R) CPU. Its MySQL version is Server version: 5.5.35-cell. I have two active wordpress sites and two inactive sites (inactive sites use for ...
2
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2answers
42 views

Optimal engine for small lookup tables in MySQL

I have following question: I am designing web application with several dozens of small lookup tables: These tables usualy contain three columns (ID, Name, Description) and a couple of rows (mostly ...
2
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1answer
39 views

Query to flatten schema

I have the following tables and columns: Users id | other-non-important-columns Containers id | Users_id | other-non-important-columns Content id | Container_id | other-non-important-columns ...
1
vote
1answer
249 views

Design advice regarding a users/groups/tasks database scheme

Here are my requirements: one user can have many tasks one group can have many task one group can have many users only invited user by a user can be added into a group Does this db design appear ...