MySQL : Open-Source, Relational Database Management System

learn more… | top users | synonyms

14
votes
0answers
3k views

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: ...
3
votes
0answers
590 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 ...
3
votes
0answers
264 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 ...
3
votes
0answers
250 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
112 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
13 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, ...
2
votes
0answers
48 views

SQL aggregate function performance in a table with many records that is well-indexed

My question is about 3 tables that stores data of a single entity, and there is a report generation feature that refers these tables and calculate COUNT and AVG information. There are three tables: ...
2
votes
0answers
35 views

How to store a 64-digit key of alpha numerical values into MySQL Database

I am student studying in Database Administration (first year), one of our task requires a to design a login form for corporate and regular users. Below are the requirements for the username and ...
2
votes
0answers
25 views

How to query for additions and deletions between two sets of rows (mysql)

I have tried several variant queries for finding additions/deletions between two sets of rows. Purely algorithmically, there is a straightforward algorithm that is O(N) for composing a list of ...
2
votes
0answers
487 views

Mysql search matching multiple values in multiple columns

I need to speed up a search. Currently we let our users input a name: John Doe Then in Java we split that string to create multiple values (or "terms") ["John", "Doe"] and loop through the terms ...
2
votes
0answers
25 views

See indices implicitly created for foreign key constaints in MySQL

When I add a foreign key constraint to my table, SHOW INDEX doesn't show any new indices, but the overall space used by the indices in that table increases. Apparently, the index for the field I put a ...
2
votes
0answers
104 views

Almost identical queries but large time difference in execution

Exhibit A SELECT SUM(value) FROM Credits RIGHT JOIN calendar ON datefield = DATE(FROM_UNIXTIME(created_at)) WHERE confirm = 1 && reason = 1 && country = 'it' && created_at ...
2
votes
0answers
72 views

Performance difference between two MariaDB slaves

I have a pool of MariaDB servers like this : master (5.5.38-MariaDB-log) slave1 (5.5.38-MariaDB-log) slave2 (5.5.38-MariaDB-log) The two slaves servers run on the exact same hardware (Dell ...
2
votes
0answers
41 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 ...
2
votes
0answers
39 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. ...
2
votes
0answers
64 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 ...
2
votes
0answers
239 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. ...
2
votes
0answers
233 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, ...
2
votes
0answers
74 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 ...
2
votes
0answers
229 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 ...
2
votes
0answers
2k views

MySQL - high CPU usage (MyISAM tables)

We have a server running LAMP stack on CentOS release 5.6 (Final) MySQL is having high CPU usage constantly which causes server to lag as shown top - 13:50:47 up 80 days, 13:53, 1 user, load ...
2
votes
0answers
254 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 ...
2
votes
0answers
56 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 ...
2
votes
0answers
3k 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 --- ...
2
votes
0answers
1k 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% ...
2
votes
0answers
95 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 ...
2
votes
0answers
95 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] ...
2
votes
0answers
818 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 ...
2
votes
0answers
104 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, ...
2
votes
0answers
910 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' ...
2
votes
0answers
1k 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 ...
2
votes
0answers
565 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 ...
2
votes
0answers
87 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 ...
2
votes
0answers
121 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 ...
2
votes
0answers
72 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 ...
2
votes
0answers
525 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 ...
2
votes
0answers
310 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 ...
2
votes
0answers
420 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 ...
2
votes
0answers
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 ...
2
votes
0answers
631 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 ...
2
votes
0answers
908 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 ...
2
votes
0answers
68 views

MySQL Partioning: Is there a performance tradeoff between number of partitions and size of each partition?

I have a large table (several 100 million rows) that I would like to efficiently partition. My question is whether there is a tradeoff between partition size and number of partitions. As far as I ...
2
votes
0answers
1k views

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: ...
2
votes
0answers
3k views

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, ...
2
votes
0answers
609 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 ...
2
votes
0answers
93 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 ...
2
votes
0answers
297 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 ...
1
vote
0answers
10 views

How to set the trigger when field(contain json value) is updated?

I have one table in which there is one field called info.This field hold json value. I want to create trigger on this field.I want to split this json format string into record I mean I want to insert ...
1
vote
0answers
22 views

Grouping results with left and inner join with zero counts

I have a query like SELECT `campaign_question_options`.`text`, COUNT(`campaign_submission_answers`.`answer`) as `count` FROM `campaign_questions` INNER JOIN ...
1
vote
0answers
11 views

Custom cycling order in MySQL

Having following Foo table: id | name | group ===|=========|====== 1 | "John" | 1 2 | "Paul" | 1 3 | "Marry" | 1 4 | "Josh" | 1 5 | "Mike" | 2 6 | "Kevin" | 2 7 | "Ramon" | 2 8 | "Kim" ...