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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2answers
465 views

How to avoid lagging when enabling log-slave-updates?

Master: 48GB RAM 16-core my.cnf: https://clbin.com/hlkUo Slave: 64GB RAM 24-core my.cnf: https://clbin.com/viLm0 Both are running 5.5.28. For the incremental backup purpose, I need to enable ...
4
votes
3answers
13k views

How to create a mysql stored procedure through linux terminal

In mysql console we will use the delimiter command to change the delimiter and it is useful to define the procedures. I understood the command delimiter for only the mysql client(client side ...
1
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2answers
665 views

Challenge. Split database 500 records in two smaller datasets, randomly

I have a database with 500 records. I want to split these records to 75% and 25% *randomly*in order to use the different datasets for training and testing to machine learning algorithms. Does anyone ...
1
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1answer
571 views

Trigger not firing when deleting a record from stored procedure MySql

Bare with me, as I'm fairly new to stored procedures / triggers. I have the following Stored Procedure: DELIMITER $$ CREATE DEFINER=`username`@`serveraddress` PROCEDURE `TASK_APPROVE`(IN idtask ...
2
votes
2answers
232 views

Repeated values in group_concat

I have two tables, first the table food and Second is Activity: INSERT INTO food (`id`, `foodName`) VALUES (1, 'food1'), (2, 'food2'), (3, 'food3'), (4, 'food4'), (5, ...
0
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3answers
928 views

Not getting the expected result with 'IN' and subquery

I am trying to access the ring_to_number from tbl_destinations that holds all the numbers. And field destinations has the comma separated ID like 1,3. but according to this query i just get the the ...
1
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1answer
591 views

Join two group_concat result

this is the query: $sql = "select pn.id, pn.purchased_number, pn.plan, pn.ring_to_group, count(rtg.id) as totalGroups, concat_ws(',', group_concat(rtg.group_name), ...
6
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1answer
10k views

UPDATE table based on the same table

I have a table with product descriptions, and each product description has a product_id and a language_id. What I want to do is update all of the fields with a language_id of 2 to be equal to the same ...
1
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1answer
64 views

Identical subquery optimisation in an update

update activitybooking set `submitted`='1' where id='958' and (select SUM(pool1_count) from (select pool1_count from `activitybooking` where `abt`='12' and (id='958' or ...
1
vote
2answers
754 views

What is the size of currently-existing tmp tables in innodb?

This is yet another "how to add a column to a gigantic table" question. The table on disk takes 2.5GB, and I have around 10GB of ram I can use. I have a feeling I can crank up the tmptablesize option ...
9
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1answer
21k views

Performance difference between MySQL and PostgreSQL for the same schema/queries [closed]

I'm a newbie DBA, and I have experience in Microsoft SQL Server but I want to jump to FLOSS. I'm starting a company, and we develop an app (PHP) with a Postgres backend, and we did some tests ...
1
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0answers
66 views

MySQL not using resources? [closed]

Hi I have a decent setup: 16Gb RAM and a 4 cored CPU. I'm on a 64-bit Windows OS with MySQL Ver 14.14 Distrib 5.5.24 Win64 (x86). I am also using InnoDB. The query I am using to test the setup is a ...
2
votes
1answer
484 views

Issues converting MyISAM table to InnoDB (auto column issue)

I'm having issues trying to convert a table from MyISAM to InnoDB in MySQL 5.6. The following is the table dump: -- -- Table structure for table `companies` -- DROP TABLE IF EXISTS `companies`; ...
1
vote
1answer
274 views

Master updates Slave but not Master itself

I have a setup master/slave in which applications are pointed only to master. Yesterday Master had got crashed due to "multi bit error on dimm detected" in Front indication panel in orange color. ...
0
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0answers
138 views

InnoDB tuning with 1G of ram limit

I am trying to calculate variable moving averages crossover with variable dates. That is: I want to prompt the user for 3 values and 1 option. The input is through a web front end so I can build/edit ...
0
votes
1answer
711 views

MySQL Read Speed and Partitioning on Separate Drives

Introduction Simple project but for an heavy read load -90% reads- over a table(~20Milion Rows ever-growing where I have to boost performance and ensure response low time for read queries) that was ...
4
votes
4answers
2k views

Why would I use the MySQL “system” command?

What can I do with the MySQL client's system command? Why does it exist? The most productive use I've seen is to look around the file system (e.g., to remember the file name you want to SOURCE or ...
0
votes
1answer
890 views

I can't install db-mysql in node.js

When I execute this command: npm install db-mysql, I get the following result. What's the solution to this problem? C:\Users\Mouad>npm install db-mysql npm http GET https: ...
3
votes
1answer
773 views

Get data from two tables with recursive relationships

I have a MySQL 5.1 DB, being used behind a PHP application to track permissions and other items that need to be issued to staff that hold various positions within an org. To track what privileges a ...
1
vote
1answer
193 views

xtrabackup backup grants?

I'm using MySQL 5.5 + Opensuse 12.3 . After face an issue with mysqldump (appear be a bug with OpenSuse Mysql distribution) I have looking for others backup solution. I found the xtrabackup from ...
2
votes
2answers
8k views

Unable to drop the table since its showing waiting for meta data lock

We are trying to drop one table but it's getting hanged, and when we see the 'SHOW PROCESSLIST' command it's showing as 'waiting for meta data lock'. Even we are unable to perform any operation on ...
0
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2answers
219 views

Database search with multi joins

I have a MySQL database and I want to perform a little bigger search. I have about 10k records in one of the tables and It's expected to grow, but slowly. The biggest problem is that to perform the ...
2
votes
1answer
5k views

Mysql Forcing close of thread 946 user

My mysql box keeping shutting down and up. Below is snippet of the log file. There is quite a number of places I notice this Forcing close of thread 946 user: 130426 12:36:28 [Note] Event Scheduler: ...
6
votes
2answers
4k views

MySQL replication: most important config parameters for performance on slave server?

I'm setting up a mysql master-slave configuration, where slave is located on a much weaker sever. Since, if I understand correctly, slave only works on updates/inserts, what are the most critical ...
1
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1answer
2k views

Database for opening times of locations

I'm designing a database for opening times and created this solution. The specifications of the database which will be a MySQL are, that a location have standard opening times in a week and can ...
-1
votes
2answers
2k views

How do I connect to a database with a blank password using a shell script?

## connect to mysql and source backup file ## USER="root" PASS="" mysql -u$USER -p$PASS database_name < backup.sql Above is my shell script which I used to source database but still its asking ...
1
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1answer
2k views

Problems in opening mysql query browser

My mysql query browser doesn't run. I just started to work with xampp and php. So I just installed xampp in my local machine. Now I have a problem in opening mysql query browser... What I'm getting ...
23
votes
2answers
43k views

Is it safe to delete mysql-bin files?

I have MM Replication in mysql, and I want to squeeze some free space in the box be deleting unnecessary files, I came across these mysql-bin files inside /var/db/mysql/ There are hundreds of those ...
2
votes
1answer
895 views

Creating a partial unique constraint for MySQL

I have the same question as asked in a previous post: PostgreSQL multi-column unique constraint and NULL values. But the solution there is not applicable as I am using MySQL instead of PostgreSQL. My ...
1
vote
1answer
259 views

Separating tables vs having one table

At the moment I have a table setup that looks somewhat like this: create table tbl_locationcollections ( id int(11) PRIMARY KEY IDENTITY, --(Primary Key), name varchar(100) not null, ...
0
votes
1answer
75 views

mysql replica ignoring server-id [closed]

I've setup a mysql replica slave a couple months ago. After a couple hickups lately, I've decide to restore it from a clean master export. I'm trying to start my mysql instance with this command : ...
1
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1answer
6k views

Is it possible for a trigger to update a row in a table using a value that was deleted?

I have a trigger which is updating a column in a different table after the row is inserted: mysql>delimiter $$ mysql> create trigger status after insert on table2 FOR EACH ROW BEGIN ...
2
votes
1answer
165 views

Changing Charset to utf8 for all the fields and tables in mysql

How should I use the mysql and awk to change the charset for all the fields and tables for a specific database? I did not include username or password, so for sure it will not work. Should I run it ...
0
votes
1answer
77 views

best relationship for this design?

There is a table users with autoincrement primary key id. There is also a table employees (every employee is a user but not vice versa). The employees primary key is userid. The field userid is not ...
0
votes
1answer
6k views

WITH ROLLUP WHERE x IS NULL

I tried to find this question somewhere else on here, and found a couple that were similar to it -- but all the answers seemed pretty convoluted, and I think it was surprising to me because I just ...
0
votes
0answers
454 views

XML Data convert to SQL database,

I have an XML feed that i need to parse daily, i want to store all of the data from the XML feed in a SQL table so then that data can be queried and manipulated by my clients. I can currently parse ...
0
votes
1answer
26 views

Which of tables key to reference?

MySQL. There is a table users with autoincrement primary key id. There is also a table employees (every employee is a user but not vice versa). The employees primary key is userid. The field userid ...
2
votes
1answer
48 views

Relational Database tables

I have a table Player where playerID is the primary key. Then I have a table Game where gameDate is the primary key (of type DATETIME). Each game is played by 2 players and each player can play many ...
1
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1answer
180 views

MySQL-test suite not included with windows mysql installer?

I noticed in my MySQL folder there is no mysql-test. Why is that? Is it possible to add it?
5
votes
1answer
14k views

MySQL: Error reading communication packets

I get this warning in mysql, [Warning] Aborted connection 21 to db: 'MyDB' user: 'MyUser' host: 'localhost' (Got an error reading communication packets) I have been through few topics in google ...
0
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0answers
82 views

MySQL replication is not happening when piping sql into mysql client

Today I noticed a very strange issue where if I cat a SQL file and then pipe it to MySQL client, replication doesn't happen. These MySQL statements aren't also written to the binlog. But replication ...
0
votes
1answer
760 views

MySQL stored routine performance while using PREPARE

Instead of maintaining stored routines for each database in my current environment I have decided to create separate database just for stored routines storage. Mainly I am using them for reporting. ...
2
votes
2answers
2k views

MySQL - SQL statement to test minimum length of the word 'ft_min_word_len'

I'm trying to understand FULLTEXT indexes. Is there some SQL query to test 'ft_min_word_len' variable? I've tried to match four characters only in the example below but it doesn't work. Why the ...
0
votes
1answer
463 views

How can I modify this trigger with loops and concat?

I have this trigger below which inserts new values in the an emplog table. I want to have my trigger insert in the description column the event that took place. For example, if I changed the last_name ...
1
vote
1answer
59 views

Is it better to add an index and search via the index or add a unique constraint and let an insert fail?

I have a table with over 2.5 million records in production that keeps track of if a specific user has already viewed an job: mysql> DESCRIBE job_views; ...
0
votes
3answers
158 views

Database migration, how to

I have two databases DB1 and DB2. In both databases exists this two tables mo_sms and mt_sms. This is the structure of those tables: CREATE TABLE IF NOT EXISTS `mo_sms` ( `id_MO` int(11) unsigned ...
4
votes
2answers
5k views

Live backup without lock

In our company we have a lot of MySQL databases. Some of these are critical and we want to take a back-up of all databases. These databases can't be locked because the application can change these ...
1
vote
1answer
272 views

mysqldump error on bash script

I'm trying to run a bash script to backup my database with Cronjob. # Backup and compress each database for database in $mysql_databases do if [ "${database}" == "information_schema" ] || [ ...
2
votes
1answer
3k views

Will OPTIMIZE TABLE have any impact on my data?

I'm having issues with a database that is getting quite slow. The analyzer in phpMyAdmin recommends that I run OPTIMIZE TABLE on my tables. But before doing so, I would (of course) like to know if ...
3
votes
1answer
376 views

Switch MySQL lag slave to new master and keep lagging (5.1)

We have the following scenario: Set of slaves replicate from the master, separate standby master (a.k.a slave with binlogs) replicates from the same master; lag slave, powered by pt-slave-delay, ...