MySQL : Open-Source, Relational Database Management System

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3
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1answer
108 views

MySQL Available Cars With multiple owners

I have a complex SQL question. We are building a car rental system. We have a car model table, a owner table and a link_model_owner table. In addition our bookings are kept in another table. Scheme ...
0
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0answers
19 views

285GB sonar db and growing, on mysql 5.5 [on hold]

we have a virtual machine that hosts Sonarcube v3.3.2 on mysql 5.5. With all our users, the database (sonardb) ended up being 30gb give or take. Later we decided to also install sonar 4.2 on the ...
0
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1answer
37 views

Query to convert existing rows to columns [on hold]

I am new to mysql and require help for reverting mysql data from rows to columns some explanations as pivoting are not working for me and i have tried multiple times ----------------------- |CODE ...
0
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1answer
32 views

How to implement Master Slave Replication using mysql [on hold]

Before moving on with question i would like to first tell you about my web project deployment architecture. Basically this website show details and values of various device connected on remote pcs. ...
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0answers
13 views

Mysql select using regexp

I have some user input i am receiving from some forms exactly in this format Names#Age#Gender#City The problem is,some forms come with incomplete data which is acceptable during the filling of the ...
0
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1answer
340 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 ...
0
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1answer
214 views

Mysql query is very slow

I am developing a website like any other social networking site using mysql. I wish it give people suggestion to my users, and I have implemented this functionality in my application, but It is ...
0
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2answers
109 views

MYSQL Optimize tables on Innodb in production environment advice

According to mysqltunner.pl I have 177 Fragmented tables. I have over 5000 tables and 200 databases. If I run optimize table on each of them, do you think I should take down the application to ...
0
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1answer
143 views

How do I write this script?

I have a very large database and I want to select certain records and then set a column value such as: SELECT name, email FROM table WHERE zipcode = 12345 INTO outfile /tmp/file.csv; Then I ...
0
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1answer
70 views

Why can't modern databases have unlimited columns [on hold]

I am just curious as to why big open source and commercial RDBMSs can't, don't or won't implement unlimited columns per table? Is there a technical or business reason why this can't be done. MongoDB ...
0
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1answer
88 views

mysqldump 5.5.25 use swap instead of memory

mysql version 5.5.25, while use mysqldump to dump big tables, it eat lots of swap while there is lots of free memory. # free -m total used free shared buffers ...
3
votes
1answer
281 views

Removing “duplicates” within a time range

I have a table that contains number plate data with a date and time stamp, collected by a plate-reading CCTV camera at a site entrance. Vehicles stopping at the site entrance will create multiple ...
0
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1answer
14 views

MySQL update one table from another joined many-to-many

I have two tables, events and plays joined many-to-many by a third table plays_in_events. Where the events.Name field is blank, I want to set it equal to the name of the play that was performed in ...
0
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1answer
25 views

I noticed that my MySQL slave's DB size is smaller than the Master's DB

I have a very simple setup of a master MySQL DB with one slave MySQL DB replicating from it. Initially, when setting up the slave, I used mysqldump to get an initial DB dump from the master like ...
1
vote
1answer
151 views

Innodb buffer pool indexes versus data usage

The server has 128GB of RAM. The innodb_buffer_pool_size is set to 106GB. mysql> show global variables like 'innodb_buffer_pool_size'; +-------------------------+--------------+ | Variable_name ...
1
vote
1answer
30 views

Impact of using UUIDs with an UNIQUE index vs. PK?

It's well known how the performance of random UUIDs as PKs in an InnoDB table degrades terribly as it increases in size. Would an UNIQUE index for a non-PK UUID column have the same impact? UUIDs are ...
0
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0answers
21 views

Receiving duplicate results in one condition of JOINED query

I always end up here when Googling for solutions, so I thought I'd cut out the middleman since I'm unable to fix this via searching/forums. It's my first time posting, so please forgive any faux pas ...
1
vote
1answer
8 views

Why MySQL init_connect variable gets updated after rebooting?

After SET GLOBAL init_connect=''; query everything works fine. However after rebooting the server or restarting the MySQL service it updates the init_connect value to some random value (OÇÿOÇÖ). Do I ...
0
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1answer
134 views

How to get names form 3 different tables

I have 4 tables to proceed. In table A I have the parameters of columns in tables B,C,D and the names are there. TB_A ...
0
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0answers
50 views

Rows are not getting deleted from MySQL Table

We have one innodb table and one Federated table in our environment and while deleting rows from Federated table it shows 24-rows affected with no warning, but rows are not deleted. There is no ...
1
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1answer
74 views

Reviewing relational database tables

I am building a database, but I am a little bit confused with my table relationships. I wish someone could help review my table relationships below for me and tell me where I am going wrong. I have ...
1
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2answers
26 views

Lost connection to MySQL server during query issue

SELECT UNIX_TIMESTAMP(a.timestamp) AS timestamp, a.adid, a.adtitle, a.cityid, a.price, a.area, a.addesc, a.subcatid, ct.cityname, p.picfile, scat.subcatname, cat.catid, cat.catname FROM xzclf_ads a ...
0
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0answers
18 views

HTML Form: Insert id into related table [migrated]

I'm relatively new to both PHP and MySQL and here's my first question: I have 3 tables. One as the "main table" and two as basically lists/categories of which I can choose and relate them to my main ...
0
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1answer
23 views

MySQL: Rank by Department in an employees table

I need Mysql query to rank the hours used by each department in an employees table, but it just ranks all without taking into consideration the departments.
1
vote
1answer
24 views

Unexpected empty result [on hold]

select a,b from table1 where a not in (select x as a from table2) AND b not in (select y as b from table3) The above query gives an empty result. Why? And how should I construct this combined ...
1
vote
1answer
391 views

Mysql Deadlock on update query on same row

My server is experiencing occasional deadlocks on two update queries on same row both using index (primary key). The conflicting queries are: UPDATE auth_user SET rep_score=185 WHERE ...
2
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1answer
29 views

1 query using OR operator in where clause vs multiple query equal condition where clause in mysql

case 1: 1 query using OR operator in where clause like select * from users where name='smith' or nick='smith' (using index_merge ) case 2: multiple query equal condition in where clause select * ...
4
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3answers
6k views

Why do the MySQL bin log files still exist after a purge or flush?

I've used PURGE BINARY LOGS as well as FLUSH LOGS, but the mysql directory still contains these files: mysql-bin.000025 mysql-bin.000024 mysql-bin.000023 mysql-bin.000022 mysql-bin.000021 ...
0
votes
1answer
16 views

Query condtion for values not being the default value?

Can I reference a columns default value directly in a query? Something like this: SELECT column FROM table WHERE column <> column.DEFAULT_VALUE Background: I'm writing a application test, and ...
0
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1answer
30 views

Where does mysql store data?

Where does mysql store data? I found out (by using mysql>SELECT @@datadir ) that it's in var/lib/mysql - but that can't be it. I have a quite big database (4 GB) called 'bot', but all the files in the ...
3
votes
1answer
655 views

MySQL error 2006 MySQL server has gone away after upgrade to 5.6.10 using homebrew on Max OS X 10.8.3

I upgraded my installation of MySQL on my Mac OS X 10.8.3 using homebrew brew install mysql Everything seemed to go smoothly, but...not really, as it turns out. I cannot add a new user (neither ...
0
votes
1answer
200 views

How to organize the tables of a MySQL database with several statistics data of several years?

I am developing an app that must provide statistics information about the distribution of the money that a person spends each year in taxes in the city where he lives. The user should select the ...
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0answers
12 views

Any way to mitigate the large server load during LOAD DATA LOCAL INFILE operations?

I'm using MySQL LOAD DATA LOCAL INFILE to load csv files, and have noticed that during these loads, server output speed to other users diminishes eg long page download times, logins timeout. The LOAD ...
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0answers
29 views

MySQL Binlog Dump process stops after net_write_timeout

We have 2 MySQL 5.6.19-1 servers with master-master replication that were working fine (DB01 and DB02). One of them was rebooted unexpectedly (DB01) and seemed to be working fine, but we saw that the ...
0
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1answer
110 views

Duplicate Relationships in Rails/MySQL Healthcare Application

Overview of the Application I am building a Ruby on Rails application to organize medications, using MySQL. The goal of this application is to provide dosage specific treatment recommendations, and ...
0
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1answer
23 views

Dealing with Mysql Replication and Functions

In MySQL replication Master-Slave, is there anyway to deal with the functions: LOAD_FILE() UUID(), UUID_SHORT() USER() FOUND_ROWS() SYSDATE() GET_LOCK() IS_FREE_LOCK() IS_USED_LOCK() ...
0
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1answer
276 views

MySQL: Prevent DROP TABLE and TRUNCATE TABLE on Slaves

Can someone tell me how to prevent the following commands DROP TABLE <tbl-name>; TRUNCATE TABLE <tbl-name>; from being replicated to slaves?
2
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4answers
271 views

MySQL: Keep the 10 most recent rows for each user

I have a table saving scores for a game that have 3 columns (more in practice, but it is easier for everyone this way): userid : the id of the user that got the score timestamp: the time the score ...
0
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0answers
10 views

What is the optimal number of worker tasks to specify in MySQL Workbench for a speedy migration?

What is the optimal number of worker tasks to specify in MySQL Workbench for a speedy migration? The default is 2. The MySQL server is running on the same Windows machine, installed with defaults. ...
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2answers
15 views

How to check/change MySQL named pipe settings?

I'm having a hard time finding anything on this because I don't know what to call it. But when you install MySQL it asks you if you want to allow connections to the database from other machines or ...
0
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1answer
444 views

Are there any disadvantages to partitioning on financial year?

Our current set up has one table per financial year (May 1- April 30). Each table has approx 1.5 million rows. We have about 8 years of data, and will obviously be adding each year. The majority of ...
0
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1answer
33 views

to pivot or not to pivot - schema design question [on hold]

I am implementing something similar to this schema http://www.databaseanswers.org/data_models/event_reservations/index.htm It occurs to me that the pivot table for Customer_Bookings would just keep ...
1
vote
1answer
658 views

mysqlbinlog failing with “ ERROR 1032 (HY000) at line 48: Can't find record in `` ” Error

I am facing some issue with PITR restore using mysqlbinlog . It is failing with the following error . # mysqlbinlog mysql-bin.000035 | mysql -u root -p db Enter password: ERROR 1032 (HY000) at ...
0
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2answers
3k 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 ...
0
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0answers
10 views

Recreate partition in mysql

I have a table having datetime column partitioned by RANGE (DAYOFYEAR(datetime_col)) By this I want to drop oldest of 4th week partition data and recreate immediately for next year similar week ...
0
votes
2answers
34 views

Merging tables, but ignoring duplicate columns

I have two tables I want to merge: city1(id, city, state, zip, lat, lon, county) city2(id, city, state) The tables contain overlapping city and state, but not primary keys. I can't figure out how ...
0
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1answer
156 views

DB disk space requirements comparision between MySQL versions

I have 2 labs where MySQL is installed. DataBases are created and deleted dynamically by certain internal processes. InnoDB is the Engine used. In one lab, MySQL version 5.0.77 is installed. The DB ...
8
votes
4answers
49k views

MySQL error: Access denied for user 'a'@'localhost' (using password: YES)

I use the root account created the account 'a'@'%'. But I can't use the it to connect to MySQL server when I specify the host parameter. I can successfully connect without the -h parameter. Please see ...
1
vote
4answers
23 views

How to alter/migrate the schema of a table with tons of records

I have a table which has about 1 million records, and recently i'm going to ship a new feature which requires 2 new fields. But I found it takes about minutes to get it finish, and during the ...
0
votes
1answer
11 views

mysql “can't create test file” error on Centos

When starting mysql on Centos servers with a custom data directory you might get an error similar to the following: 2014-10-15 10:23:56 17081 [Warning] Can't create test file ...