0
votes
0answers
26 views

Moving datadir OK start, but socket error for mysql client

I'm trying to move my MySQL datadir from /var/lib/mysql over to /home/mysql (an ssd drive as I'm having iowait issues on /var/lib/mysql when MySQL is running on that drive). The OS is CentOS 5.6 ...
0
votes
0answers
38 views

Show single value of one column for multiple rows of other columns

I have a SQL query which displays my data results like this. date emp_id emp_name spent_hours 19-08-2013 1024 jack 10 19-08-2013 1024 jack 11 19-08-2013 1024 jack ...
0
votes
1answer
16 views

How to access another Connect server table in my Local server in SQLyog 7.01?

In same server name using same database select * from area;(Working Good) Same Servername but Different Database select * from mysql.event(Working Good) Now i am connection TWO Different server ...
0
votes
1answer
20 views

How to restore data after MySQL Upgrade?

I upgraded from MySQL 5.5 to 5.6 by uninstalling 5.5 and then installing MySQL 5.6. Now that MySQL 5.6 is running, none of my DBs or data is present/visible in MySQL Workbench. I also see that I ...
0
votes
0answers
14 views

self join of single table to find time difference of adjacent rows of a single column which are not in sequence

I want to find the time difference between two adjacent rows of a single table which are not in sequence.i made a self join of table and tried but i did not achieve what i need .can anyone please help ...
5
votes
1answer
268 views

Is it Possible to Recover Data from a BLACKHOLE table? [closed]

I had created table with engine BLACKHOLE basically the BLACKHOLE storage engine acts as a “black hole” that accepts data but throws it away and does not store it. Retrievals always return an empty ...
2
votes
1answer
21 views

Mysql INSERT INTO .. ON DUPLICATE KEY UPDATE

I'm trying to do the following query in mysql 5.5 INSERT INTO countingTable( image_count, article_id ) SELECT COUNT( article_id ) AS sum, article_id FROM imageTable ON DUPLICATE KEY UPDATE ...
0
votes
1answer
19 views

Mysql closing immediately after new installation

I am using mysql as an backend for my webapp ,the software ran without any glitch but today it gave unexpectedly ERROR:2003 i tried many solution on the internet but none worked. so reinstalled the ...
2
votes
1answer
53 views

Auto_increment value needs to be set as S1

Hi I need to set auto increment for a table as S1. I tried by altering the table and also by creating by new table I am aware how to set auto_increment but when i try to set auto increment as S1 i am ...
1
vote
2answers
42 views

How to get “mysqlbinlog” utility for Ubuntu?

I can't find "mysqlbinlog" utility in my Ubuntu server, i can see mysql, mysqldump, mysqlshow etc... command line utilities but not mysqlbinlog utility. Can someone please help me from where I can ...
1
vote
1answer
54 views

Different column for different conditions when joining

I am using MySQL database and in that two tables, relation is one to many. One table is product table, sample data: +----+----------+ | id | name | +----+----------+ | 1 | product1 | | 2 | ...
2
votes
1answer
33 views

WHERE attribute having two relation lines in the same SQL

I have a database designed with tree tables: checklist (id, name) tag (id, name) checklist_tag (checklist_id - FK, tag_id - FK) Running this SQL: SELECT cc.id as checklist_id, cc.name as ...
0
votes
2answers
68 views

Database Design Help: MySql/PostgreSQL Single Database/Multiple Databases

We are planning to build a web based custom business analytics tool using PHP and MySQL/PostgreSQL. In our application, we are planning to upload customer’s data using a Excel sheet and these data ...
-1
votes
1answer
51 views

mysql server is not starting

mysql server is not starting after modifying configurations key_buffer = 16M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 query_cache_size = 16M after ...
0
votes
0answers
45 views

amazon small instance mysql query too slow

I have mysql database with 1.5 millions records with 2 million categories records. when i do query on categories and city where clause it takes 304989 milliseconds. on localhost it too fast. i tried ...
0
votes
2answers
38 views

query execution time in mysql

I have run the query in mysql which consists of approximately 33million records when i have executed the query select population1 < 200000 from city; it shows like this after execution ...
0
votes
1answer
18 views

change character set in mysql permanently

I want to change following parameters to utf8mb4 so that mysql can store emoji characters and special language characters. but when i try running following statements one by one SET ...
0
votes
2answers
38 views

Using a join to return multiple values of the same column?

I have two tables user Rank In the Rank table, I saved rank_id and supervisor_id. In the Rank table, I stored the rank name. The rank_id and supervisor_id are foreign keys from the Rank table. ...
-1
votes
1answer
39 views

Btree index and Bit Map Index [duplicate]

Please clarify the difference between BitMap Index and Btree index. I am using mysql version 5.5.37-0ubuntu0.12.04.1. I can able to create Btree index but unable to create the same, Please find the ...
0
votes
1answer
42 views

Could not access database

I have been trying to setup a local instance for a new application. I am new to MYSQL and I cannot understand how to actually connect this database to the actual web application sitting in the ...
1
vote
2answers
24 views

getting one day timestamp in mysql

Please consider the following stored procedure I have: ORIGINAL Stored Procedure: -- -------------------------------------------------------------------------------- -- Routine DDL -- Note: comments ...
0
votes
1answer
51 views

How performance schema in mysql 5.6 improve performance?

Since MySQL 5.5 performance_schema database has been added likewise information_schema. As we know that tables in information_schema contains statistical information like tables, plugins, partitions, ...
1
vote
2answers
67 views

Are there benefits to using more than 4 CPUs for MySQL?

We are running MySQL 5.5 on linux under VMWare, running on 2 CPUs. We are planning on increasing this to 4, but we have un-used CPUs available, and I'm wondering if there is any benefit to increasing ...
2
votes
2answers
82 views

How to monitor InnoDB Disk I/O using Server Status Variables?

This question is extension of my previous question "How to monitor InnoDB Disk I/O Required for MySQL? " As mention in my previous question i want to count total number of disk i/o per query, but ...
1
vote
1answer
44 views

Safely changing innodb_buffer_pool_size on MySQL replication master?

We have a MySQL server which is a replication master. We need to change the innodb_buffer_pool_size and innodb_flush_method to (hopefully) improve performance as the database has grown. What is the ...
0
votes
1answer
64 views

Dedicated mysql server slow response [closed]

I have server in Kimsufi with 2gb RAM but my server is very slow , with simple hosting in ovh it responds quickly ... With pingdom.com test i have for server: 10 sec and simple hosting: 2sec is ...
0
votes
1answer
35 views

Two MySQL requests at the same time - Performance issue [closed]

I have a MySQL server with many innodb tables. I have a background script that does A LOT a delete/insert with one request : it deletes many millions of rows from table 2, then insert many millions of ...
0
votes
0answers
21 views

output from mysqltuner.pl (from mariadb.service)

While running mysqltuner.pl script, I'm getting following message: [OK] Currently running supported MySQL version 5.5.35-MariaDB-log [OK] Operating on 64-bit architecture -------- Storage Engine ...
0
votes
0answers
40 views

mysql service failed to start when datadir changein ubuntu

I have dual Operating system on PC, windows 8 and ubuntu 14.0, and I am mostely using ubuntu because my MySql database is hosted on ubuntu. Recently when I am trying to restore my database, which is ...
0
votes
2answers
62 views

MySQL Community Edition Capacity

I am using MySQL Community Edition on Amazon RDS service. It is a very large database, 2/3 tables has about 10 millions records and 4-5 tables has 7-8 millions records. Questions How much capacity ...
0
votes
0answers
29 views

tables don't exist after unmounting and remounting external drive where database was installed

I want to create a database that's too big to keep on my own machine, so I'm trying to create one on an external hard drive. It works up until I unmount and remount the drive, at which point show ...
1
vote
2answers
38 views

MySQL user without SUPER privilege

This may be a simple question and may not be the right place to ask but I couldn't find any useful information from Google. Here is my question. When creating users in mysql using grant all ...
0
votes
1answer
23 views

ON DELETE CASCADE pseudo delete

For data integrity ON DELETE CASCADE is necessary but it's really dangerous when a delete affects like a Chain Reaction! I know one way to prevent this is to make a pseudo delete by putting a ...
0
votes
1answer
49 views

Select post and concatenating all categories it belongs to

I have 3 DB tables POSTS +----------+----------+----------+ | id | title | content | +----------+----------+----------+ CATEGORIES +----------+----------+ | id | title | ...
2
votes
4answers
227 views

Aggregate query optimization

Could you please help me to optimize this query - currently it takes ~4 minutes to run this query. It looks like keys: ip and timestamp are non-unique so shall I add some indexes? mysql> EXPLAIN ...
1
vote
1answer
75 views

Master-Master Replication Duplicate Key

I have set two servers master-master replication mysql , i manage to set successfully but the problem is the duplicate key i got MASTER 1 Configuration /etc/my.cnf [mysqld] server-id=1 bind-address ...
0
votes
1answer
69 views

Whether to use or not to use: DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

In one Database table, created_at & updated_at are defined as: `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP `updated_at` timestamp NOT NULL DEFAULT ...
-1
votes
1answer
47 views

Query to retrieve data based on several where conditions ( Not off Topic , Answer provided below is right ) [closed]

Database : Mysql 5.5 i have a table T1 containing 4 columns : No. , Height , start_time , end_time In column height i have 3 distinct values only : Small Medium High Now i ...
0
votes
0answers
39 views

Log-slave-updates in multi master replication using Tungsten replicator

I m setting up a system as follows with 2 masters and 2 slaves. M1 <----> M2 (Tungsten Replication) M1 ----> S1 (MySQL Replication) M1 ----> S2 (MySQL Replication) I have enabled the ...
1
vote
1answer
36 views

Is there a product to auto-build indexes based on slow queries?

I'm looking to either find, purchase, or write a script to identify slow queries, identify potential missing indexes, and when needed create the appropriate index within a reasonable amount of time of ...
0
votes
0answers
42 views

Upgrade from mysql 4.1 to mysql 5.5

I was going through upgrade process of mysql server. It is mentioned that to upgrade from 4.1 to 5.5 we need to upgrade step by step like first to 5.0,5.1 ...5.4 and then 5.5. I have some questions : ...
2
votes
0answers
20 views

MySQL slow query log not logging all slow queries [duplicate]

I am trying to analyze the hibernate query performance in our application. I tried logging all hibernate queries which take more than 100ms execution time from application side as well as using mysql ...
0
votes
1answer
28 views

MySQL database configuration for fastening the select and insert queries

There are several DBEngines are available for MySQL DB. Currently I'm using InnoDB. My actual problem is, I have a table that consist of millions of data. Therefore the select queries that given to ...
0
votes
0answers
11 views

Will performing a physical copy of a MySQL database on Windows to a MySQL instance on Linux still perform? [duplicate]

I'd was told you can copy text files and such from Windows to Linux just fine, I was wondering if I could copy my innodb files such as .ibd and .frm files to a mysql instance running on Linux, fire it ...
0
votes
2answers
18 views

Joining on 3 different keys as they're set

I have these tables: TABLE vessels ID int PK organization_id int FK fleet_id int FK name VARCHAR TABLE settings ID int PK organization_id int NULL FK fleet_id int NULL FK vessel_id int NULL FK ...
0
votes
0answers
31 views

stress testing mysql - maximizing qps for a single user

I am running a stress test and I am trying to churn out as much qps as I can for a single user. I know this is a loaded question so I will try to be more specific. Trying to target 30,000 qps with a ...
1
vote
1answer
34 views

Will composite indexes or unique indexes help with query performance?

I need help with identifying indexes to increase performance of the following query. I'm currently using v5.5 with InnoDB. I cannot modify the query. However, I can add indexes as needed. The ...
0
votes
0answers
18 views

How can I determine the performance (rows/second) for a certain query on one of my tables?

I want to find the performance (rows/second) for an UPDATE query on one of my tables so I can adjust my WHERE clause to select an appropriate number of records. The table has around 10 million rows. ...
1
vote
1answer
56 views

Slow queries InnoDB occasionaly

I have the next table: CREATE TABLE `sessions` ( `session_id` char(32) COLLATE utf8_unicode_ci NOT NULL, `session_expires` int(11) NOT NULL DEFAULT '0', `session_data` varchar(10000) COLLATE ...
0
votes
0answers
17 views

How to ensure accents are view as different characters when adding to unique indexes?

What can I do to ensure MySQL views the following as two different values? Bee Bée When I try to create a unique index, it fails because they're the same value. I looked at the following thread, ...