MySQL : Open-Source, Relational Database Management System

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MySQL 5.1.66 SSL connection error ERROR 2026 (HY000)

UPDATE2 Using WireShark I found out the problem string (I hope I did): 28 | 9.582638 | 192.168.18.128 | 192.168.18.129 | MySQL Response Error 1043 And the error is (according to docs): Error: ...
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74 views

3 table merge with some condition

I am new to this forum and I am learning mysql with the help of online resources, currently I am trying to compare and merge table with some conditions Fiddle These are my tables; ...
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191 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 ...
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96 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. ...
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34 views

Emulating WITH clause in MySQL/query perfomance review

I have never really worked with MySQL queries till this last week. I was tasked with making a simple tool for my department that tracks contacts. Here are the 2 tables and the type of data they ...
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28 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. ...
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54 views

Denormalizing to speed up inserts

I have a MySQL InnoDb table with approximately 40 million rows and the following columns: param1 (int), param2 (int), param3 (int), geo (char2), value1 (bigint), value2 (bigint) I have an ...
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37 views

Proper design of routes in Database MySQL

I'am trying to find out the best database design and try to stick with data integrity by using Foreign Keys. But I'm stuck right at the beginning because of limit relations between tables with FK to ...
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26 views

Difference of write authorization on file system with mySQL

On my local mySQL (on CentOS 6 VM) database I wanted to export some data from the DB to a file like this: SELECT html FROM mytable WHERE lang = 'en' and id='KEY01' INTO OUTFILE 'key01_en.html' By ...
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164 views

How can I connect to a network MySQL server using ODBC?

Somewhere on my company's network there's a (Oracle) MySQL server named FOO. I see FOO reference in SAS code written by my team's analysts, who use SAS's PROC SQL command to connect to it using ODBC. ...
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114 views

Recover innodb database from ibdata1 and *.frm files only

I have a problem on my server. I had a hard disk error on my server, and I restarted it. After that, I started wamp server software, but mysql services were not started. I checked all mysql data, ...
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48 views

Single database won't load MySQL

When I turned off my MySQL server, and turned it back on, it wouldn't read my database anymore. Just a single database, everything else in mySQL was fine. When I try looking at any of the tables it ...
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149 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 ...
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112 views

How to model (a many to many) to many relationship

Hello i am facing the following scenario. I have a student table with the following structure. Student id(PK), matriculation number, first_name, last_name, email A student can have more than one ...
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45 views

Count how many locks required for a MySQL (InnoDB) query

I'm performance tuning a very data-heavy mysql application. It has a purge system that often seems to cause lock timeout errors for users. Based on my research I have a few adjustments to the query to ...
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905 views

MySQL Queries taking too long to execute

I have a database table, with 300,000 rows and 113.7 MB in size. I have my database running on Ubuntu 13.10 with 8 Cores and 8GB of RAM. As things are now, the MySQL server uses up an average of 750% ...
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92 views

Understanding Indexes and using them better

I've been spending some time trying to optimise our MySQL queries that we use which essentially joins one table with 2 million rows onto another which has 1-2 million. I know MySQL is able to easily ...
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79 views

Does it make a difference to add the DEFAULT keyword in CREATE TABLE?

The MySQL manual says: CREATE DATABASE db_name [[DEFAULT] CHARACTER SET charset_name] [[DEFAULT] COLLATE collation_name] ALTER DATABASE db_name [[DEFAULT] CHARACTER SET charset_name] ...
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575 views

Mysql slow writes

i have a strange problem with mysql. My selects goes fast. My insert/create/delete/drop/update go very slow. I have done some tests on 2 machines. My old machine and my new machine. Old is worst ...
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91 views

Why does MySQL force the tradeoff between swallowing errors and leaking commits in transactions?

Referring specifically to the choice of whether to use DECLARE EXIT HANDLER FOR SQLEXCEPTION. If you use it, you swallow errors and there doesn't seem to be any way to access them programmatically, ...
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648 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' ...
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903 views

How to prevent “ibdata files do not match the log sequence number”?

I am dealing with a very large set of databases that are all innodb. I've enountered this on mysql restart too many times for my comfort: ibdata files do not match the log sequence number But I've ...
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281 views

Insert Speeds for large batches

In my application, my INSERTs seem to be taking a major chunk of the time. I have a large number of objects in memory (~40-50,000) which i want to insert into a table. Lets take a sample table ...
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413 views

The nature of the relationship between two tables in MySQL

Good day. I'm designing a database for a research project where we're predicting whether or not young female athletes will rupture their ACL(s) based on the nature of a test jump recorded with a ...
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179 views

InnoDB forum DB design and Composite Primary Key (Cluster Primary Key)

I am designing forum database using InnoDB and got few questions , Could any one please help me to clarify them? Posts and Comments table design below CREATE TABLE `my_posts` ( `forum_id` ...
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386 views

To what extent is MariaDB Java client a perfect replacement for MySQL JDBC (Connector/J)?

Premise: I ship a Java application which will make a JDBC connection to a MySQL database. (At the time of this writing it could be 5.1 or 5.5, but hopefully the question and answer don't rely heavily ...
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81 views

MySQL Partitioning Performance

I have a MyISAM table with billions of rows that is still causing me problems because the indexes, even after I shortened them as much as possible, do not fit in my 64GB of RAM. I am unable to index ...
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236 views

Storing history of full/partial tables

I'm building a web-application with Django and MySQL (InnoDB) and am currently pondering over how to manage historical changes on various tables. I wonder if it's efficient to store a lot of rows ...
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110 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 ...
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63 views

How can one improve the performance of a query that selects on a low cardinality column in MySQL?

I have a "State" column that has a low cardinality (three possible value), on which most of my queries perform an equality selection (WHERE col = 'blah') AFAIK you need something like a bitmap index ...
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426 views

MySQL: Improve performance for one row insert into table with unique constraint

I have a table with ~ 40 mil records, with a unique index on the url collumn, of type varchar(255). Now the insert speed is about 30/s, is this expected? how could I improve it? I can't use bulk ...
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248 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 ...
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343 views

Incorrect data when we using the CONVERT_TZ function on DST boundaries

We have a problem in converting time zone from "America/New_York" to "UTC". This problem occurs only on times representing 2.00 AM during the daylight saving. Timezone conversion with correct output ...
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2k views

'Access Denied' in MySQL on AWS RDS

I'm trying to use an ETL (in my current case, the free version of Talend). I've successfully set up a MySQL on Amazon RDS, logged in through the MySQL Workbench for Mac, and uploaded my company's ...
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542 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 ...
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834 views

MySQL Server hitting 100% unexpectedly (Amazon AWS RDS)

We've been struggling with this issue for months. This week we upped our RDS instance to the highest performing instance and although the occurrences have reduced, we're still seeing our database ...
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MySQL re-install fails under Mountain Lion

I have problems to reinstall MySQL on Mac OS X after it was running on my system. I uninstalled it because the PreferencePane wasn't working as expected, using the procedure described here: ...
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mysql taking too long to send data

I have a simple table with million of records (14,000,000) and for a simple query it is spending too much time "sending data". The table CREATE TABLE IF NOT EXISTS details ( id int(11) NOT NULL, ...
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513 views

Index usage for database server

How can i fix the Index usage on one of our database server? It says from our Nagios control panel that: Service: DB Index Usage Host: MySQL Cluster Address: ( our IP ) State: CRITICAL Additional ...
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89 views

Can't connect to MySQL Cluster Storage (data) nodes

I've deployed a MySQL Cluster with a few nodes, and I want to access the storage nodes directly from another machine using NDBAPI. When I tried to connect from the same host it worked, but when I try ...
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270 views

MYSQL & Access ODBC

I am trying to connect mysql with access, i am settings up the ODBC correctly from the data sources, however i get a driver error. I am using access 2010 and the driver version of the ODBC conector ...
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12 views

MySQL instance stalling - due to InnoDB log flushes?

An instance of MySQL 5.6.20 running (mostly just) a database with InnoDB tables is exhibiting occasional stalls for all update operations for the duration of 1-4 minutes with all INSERT, UPDATE and ...
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43 views

Query does not use index (according to EXPLAIN SELECT)

Can anyone give me an indication, why this query does not use the Key on the table 'gtg'): ...
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18 views

Mysql syntax error when i add on completion preserve

I have written this event in mysql DELIMITER $$ CREATE EVENT le_drop_database ON SCHEDULE EVERY 1 WEEK ON COMPLETION PRESERVE STARTS CURRENT_DATE + INTERVAL 4 - ...
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35 views

Many small queries or one single query

This is not exactly a question, more of a survey. Here at BlackBean we have a time series aggregation and analysis platform built on top of MySQL, where each client have your own database, and each ...
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32 views

MySQL 5.1 High Cpu usage on CentOS 6

I am running MySQL 5.1 on a CentOS 6 server with 16G ram. I got also apache on it. MySQL is constantly using too much cpu. top - 17:40:36 up 112 days, 12:13, 1 user, load average: 1.24, 1.72, 1.82 ...
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MySQL Memory & max_connections Performance Tuning

So, our site runs WordPress and in the past few days we have been getting tons of spam comments etc. I believe that we are becoming the victims of some kind of bot army that has been crashing our ...
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35 views

How to measure bandwidth requirements for MySQL, Postgres, …?

TLTR: how to configure MySQL/Postgres to get a fair measurement of the I/O requirments for analytical queries? Hello, for certain database and especially database hardware experiments for want to ...
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Why do these two queries (which I think are equivalent) rely on different keys?

We have a query that we don't like, since it ends up doing a full table scan. EXPLAIN SELECT count(*) AS c, location.name FROM study LEFT JOIN location ON study.location_id = location.id ...
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25 views

Problem when using gtid with MySQL replication

I have faced to problem when using gtid in MySQL replication: "When @@SESSION.GTID_NEXT is set to a GTID, you must explicitly set it to a different value after a COMMIT or ROLLBACK. Please check ...