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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7
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0answers
108 views

Avoid MySQL self-crashing on long semaphore waits

I run heavy queries on my InnoDB databases every night, and sometimes it causes long semaphore waits. More background in this question. What I have observed is that if the data is stored on an SSD, ...
6
votes
0answers
69 views

How to estimate the I/O operations performed by MySQL queries?

On Amazon's RDS, you pay about $0.10 per 1 million I/O requests. I've noticed a very high number (in hundreds of thousands) of I/O requests for a very low traffic database. On seeing this, I did some ...
4
votes
0answers
40 views

Nothing to do, no schemas or tables selected on export

I'm using MySql Workbench 6.3.6, on Windows 10, which has all updates. I have previously been able to get a data dump from this database. Now I can't get any from any of the schemas I have open in ...
4
votes
0answers
347 views

RDS MYSQL instance rebooted and won't load INNODB table

So my production db in RDS apparently either crashed or was rebooted during a version update, and upon being restarted mysql couldn't load one of the innodb tables: as evidenced by the following error ...
4
votes
0answers
7k views

How to use SUBSTRING using REGEXP in MySQL

I have the following situation. I have to substring regular expression from description using MySQL. Description: Lorem D9801 ipsum dolor sit amet Where D9801 is REGEXP. Every strong text ...
3
votes
0answers
18 views

insufficient history for index

In MySql log, there is one error `InnoDB: insufficient history for index 0' I don't know why its occur. I have done google and found following ...
3
votes
0answers
78 views

MySQL process stuck on “cleaning up”, locking table forever

It was suggested I post here as opposed to StackOverflow. I'm new to debugging mysql/innodb issues so here is the best I have: I'm trying to run an integration test so these results are near ...
3
votes
0answers
50 views

Why does replication with SSL fail on my MySQL database in AWS RDS?

I'm trying to replicate from AWS RDS to my own server. It works without SSL. Whenever I include the SSL property to the slave, it breaks with this error: error connecting to master ...
3
votes
0answers
41 views

mysqldump with --skip-grant-tables

It appears the files in my /var/lib/mysql/mysql are borked, and I can only start mysqld with --skip-grant-tables. Now I want to export all tables with mysqldump --all-databases, wipe and reinstall ...
3
votes
0answers
49 views

How does mysql(innoDB) handle same foreign key for join

I have a table called X and another called Y. There is a primary key on Y that is a foreign key on X. Now, my data is such that there will be many rows in X that will have the exact same foreign key ...
3
votes
0answers
39 views

MySQL optimizing - use ram instead of CPU?

I am on a dedicated server with Intel Xeon D D-1520 4/8t 2,2 / 2,6 GHz, 32 GB of RAM DDR4 ECC 2133 MHz, and 2 x480GB of SSD SOFT. The problem I am encountering is that MySQL eats up all of my CPU ...
3
votes
0answers
795 views

invalid default value (mysql 5.7) for timestamp field

EDIT: When updating an existing database from mysql 5.6 and executing: UPDATE phppos_register_log SET shift_end = '2015-01-01 00:00:00' WHERE shift_end = '0000-00-00 00:00:00'; This produces: #1292 ...
3
votes
0answers
82 views

Create an SSL connection with ODBC driver to MySQL(5.6) using openSSL

I want to create an asymmetric SSL connection from MySQL to an ODBC driver but don't fully know how to generate the keys and certificates (I'm using openSSL as recommended here: ...
3
votes
0answers
76 views

Flexible and robust way to cull older data?

I am no DBA and that is becoming more apparent daily, as such I am having trouble keeping my query times reasonable. I have about 3.57 Million records ( at about 3.43 GB ) and it takes about 2 minutes ...
3
votes
0answers
64 views

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. ...
3
votes
0answers
489 views

How to get the best write throughput during a MySQL import with Amazon RDS?

tl;dr - How can we get the maximum EBS throughput for a db.r3.2xlarge instance? We're only seeing about half of what it can supposedly do. Apologies for the long length of this question. We've had ...
3
votes
0answers
67 views

mysql workbench connection type tcp/ip over ssh with libpam-google-authenticator enabled

I'm attempting to connect to my MySQL Database using the Connection Method "Standard TCP/IP over SSH". I filled out all the SSH and MySQL connection details correctly, however I get the message: ...
3
votes
0answers
202 views

Combined UUID Index + AI PK Insert Performance

I posted this in stackoverflow but realised it probably belongs here instead. Imagine the following table: CREATE TABLE `orders` ( `ORDERID` int(11) unsigned NOT NULL AUTO_INCREMENT, ...
3
votes
0answers
59 views

Sample a Mysql table to increase performance

we are storing all our clients traffic data in a MySQL 5.1.73 database (MyISAM) and then we use it to generate user and internal statistics/graphs, always searchinng for a client id and a date/hour. ...
3
votes
0answers
286 views

utf8mb4 in SQL Server Express

We have some web applications based on databases using utf8mb4 as character set and utf8mb4_Standard as collation. We saw that we can use any character we want with this setting. In SQL Server ...
3
votes
0answers
69 views

Tagged questions

I have similar to StackExchange network that utilises tagged questions. In my web application Users also can find questions by tags. The query below returns a set of tagged questions: SELECT ...
3
votes
0answers
7k views

Why does CAST(1 AS SIGNED INTEGER) return a BIGINT on MySQL?

If I do CAST(1 AS SIGNED INTEGER) I always end up getting a BIGINT returned, for example: $ mysql -u root -p --column-type-info Enter password: --- Copyright and help message snipped for brevity --- ...
3
votes
0answers
985 views

Getting distinct list of records based on the MAX of a column

I have a status table (tblTestActionStatus) which has three columns ID_TestAction: references some test action ID_Status: a look up table reference for the variety of possible statuses for the ...
3
votes
0answers
2k views

Query getting periodically stuck in 'copying to tmp table' state, never completes

I am running Wordpress on a dedicated server with a MySQL backend. I have a query that usually takes <1 second to execute, but periodically, this query will get stuck in a 'copying to tmp table' ...
3
votes
0answers
100 views

Table Structure: 2 Related Entities Share the Same Entity

I was hoping I could get some advice on my table structure. Im writing a simple workout tracker for me and my buddies. These are the requirements: Multiple users A user can have multiple workouts A ...
3
votes
0answers
161 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 ...
3
votes
0answers
3k views

Achieve PostgreSQL hstore functionality in MySQL

Please suggest any MySQL 5.5+ Engine that can support collection of key-value pairs be stored in any column of a table. I don't know if this feature is available out of the box in MySQL like ...
3
votes
0answers
490 views

Dynamic MySQL partitioning based on UnixTime

My DB design includes multiple MYISAM tables with measurements collected online, Each row record contains auto-incremented id, some data and an integer representing unixtime. I am designing an aging ...
3
votes
0answers
407 views

“InnoDB: error clustered record for sec rec not found” MySQL 5.5.28

We have a high-end server, 128GB RAM, 32 Core , Xeon, SSD RAID 10 - running Ubuntu 12.04 with MySQL 5.5.28. During high load, randomly we got the below error. MySQLcheck, innochecksum shows no ...
3
votes
0answers
127 views

Once in a while synchronization of the independently updated mysql databases problem

I have a production database and a test database running on MySQL with MyISAM and InnoDB tables, which are updated independently. The Production database is updated by system and sometimes by a user. ...
2
votes
0answers
57 views

mysql trigger on a federated table

I have two MySQL(5.6) databases D1 and D2 on two different machines. There is a table T1 on D1 and there are two tables T2A and T2B on D2. I want to update T2B whenever T1 is updated. T2A is a ...
2
votes
0answers
47 views

MySQL: Is the read committed isolation level safe with mixed binary log format?

When using the MIXED format with the READ COMMITTED isolation level, am I safe? The docs state (http://dev.mysql.com/doc/refman/5.5/en/set-transaction.html#isolevel_read-committed) If you use ...
2
votes
0answers
48 views

MySQL high performance difference between two similar databases

I'm currently upgrading from TecDoc 2015 Quarter 2 database to TecDoc 2015 Quarter 4 database. Q2 Database: 240,838,107 rows InnoDB utf8_general_ci 23.2 GiB Q4 Database: 265,508,380 rows ...
2
votes
0answers
61 views

How to check wether a DB2 source table and their MySQL MyISAM duplicate are identical?

I want to compare two big tables if they are identical. If I update/insert one table into the other the process takes about 11 hours. What I am looking for is like a sum function which sum ups a key ...
2
votes
0answers
20 views

a story about a bad replication issue - insight needed MYSQL

A id val B id A_id We are not sure of what happened but it appears that when replication occurred on a series of these two table datasets, that A failed replication, but another insert got the lost ...
2
votes
0answers
33 views

Mysql stored procedure SQLEXCEPTION

Below is my sample query, in which I first create new folder then update count then create a new tag and finally get new id. insert into folder (name)values("new"); update folder set count = count + ...
2
votes
0answers
34 views

Mysql log table

I have a logging table that contains 3 fields Id action time The time column is 11 digit integer. Our goal is that each month the logs of the prior month will be deleted. It is possible to do with a ...
2
votes
0answers
188 views

mysqldump vs mysqlpump

I just heard about mysqlpump - it looks like it was released with MySQL 5.7, however MySQL 5.7 still includes mysqldump. They're both backup programs, but could anyone summarize the main differences? ...
2
votes
0answers
44 views

Database Architecture & Design

I am building a web application for project management which will be hosted on my servers. My application design is like this 1 - user register 2 - domain name will be created i.e ...
2
votes
0answers
89 views

How to start MySQL after the year 2038?

I am using MySQL 5.5. For some reason, I need to change the date of my system to after 2038. Unfortunately, the MySQL service won't start after the year 2038: root@sd-84962:~# date Sat Sep 24 ...
2
votes
0answers
55 views

Identifying table causing runaway rollback in MySQL 5.5 (InnoDB / Windows)

I have a large database (180 GB), running under Windows, with a runaway rollback that starts running as soon as the database is started up. I have started the database with innodb_force_recovery=3 ...
2
votes
0answers
37 views

Composite index works for larger set of data, but not smaller

This is a follow on question to optimise my.ini for key query Data model: DROP TABLE IF EXISTS `contract`; CREATE TABLE IF NOT EXISTS `contract` ( `id` int(11) NOT NULL AUTO_INCREMENT, ...
2
votes
0answers
25 views

Insufficient Prilivege for Function

I'm using a Function that I can't read, when I try to open it, I can't see the definition. I get following error Error : Insufficient privilege. Nevertheless, it is being executed by my app ...
2
votes
0answers
17 views

Join integration query involving multiple associations

I'd like some assistance in fixing this query. Let me explain the background on what it currently does, and then what I need to integrate. First, here are my current tables. users (performers) table ...
2
votes
0answers
38 views

Mysql History Trigger Auto Increment bug or problem

I want to log history of a table, I created a history table and triggers for update,insert and delete operations. I do my test on realtime replication slave. When a record inserted master's main ...
2
votes
0answers
143 views

Issues with mysql enterprise backup, assertion failure on restore

I'm trying to restore a backup to a new server, but having some issues with corruption. The source server has a 2.5T table which is very active. I copied the latest backup over to a new server and ...
2
votes
0answers
36 views

selecting data from joomla back end mysql

I have developed a front-end that call a php server side service that adresses the mysql. On my local everything works perfectly, but on distant 1and1 machine, it only works for tables created by ...
2
votes
0answers
59 views

How can I organize complex queries?

I am analysing a relatively large (25GB compressed MySQL dump) static data set. Some of the queries I'm writing are several tens of lines long, which makes them difficult to understand, modify, and ...
2
votes
0answers
31 views

Caching impression counts to avoid mysql inserts

We currently get a lot of mySQL inserts/updates on duplicate daily (millions) and we're looking at speeding up the application by using some form of counter with memcached and then clearing it on ...
2
votes
0answers
127 views

How to store data where various subcategories have specific columns?

I'm new to database designing. I'll use MySQL and PHP. I'm designing a database in which I have a lot of categories and subcategories like given below: Product Table p_id p_title category_id ...