MySQL : Open-Source, Relational Database Management System

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Mysql giving only 25 inserts per second

I'm using ubuntu 12.04 LTS Processor : Pentium(R) Dual-Core CPU E5200 @ 2.50GHz × 2 OS Type : 64-bit Memory : 3.9 GiB Disk : 101.1 GB I installed mysql and wanted to test insert performance. Here is ...
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1answer
116 views

Slow MySQL query, not sure why

I'm working with an intranet application for property tax collection, and I've hit a snag. The following view runs much slower than I'd expect: create or replace view propertytaxessub0 as select ...
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3answers
325 views

Is this database fine for calculation?

I am doing an application called as Invoice Application.For that I have my database is like this. Now my problem comes when I am taking the tax part in my database.As I have made tax as an option ...
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How can I force myisamchk to modify the original data file in case of duplicate keys?

In the documentation for myisamchk, it says: --quick, -q Achieve a faster repair by modifying only the index file, not the data file. You can specify this option twice to force myisamchk to ...
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1answer
816 views

MySQL Master-Slave Replication Cross Database

I am setting up Replication for cross Database as i have set 2 variables in Slave' s my.cnf as replicate-do-db=database_name and Replicate-wild-do-table=database_name.% ,But i am not able to get ...
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2answers
2k views

MySQL cluster - how many hosts are needed for full HA?

I need some clarification on MySQL-Cluster (NDB) setup I want to achieve full HA but I'm low on server budget and can't afford to rent a dozen of servers for simple solution that I'm working on. ...
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1answer
382 views

Stored procedure arguments get immediately truncated

I have a stored procedure with a single SELECT statement inside: DROP PROCEDURE `pos_neg_test`// CREATE PROCEDURE `pos_neg_test`(IN start_ts TIMESTAMP, IN end_ts TIMESTAMP) BEGIN SELECT ...
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MySQL Database Schema for Train Timetables

I am interested in what a MySQL database schema would look like for a train timetable. Generally this is presented in table format as the final result. Train No. 11111 22222 11111 Train Day ...
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1answer
399 views

What is the underlying representation of BLOB data when I export it?

When I export a blob object to an SQL file, I get some thing like this for a blob field: 0x4f3a383a227374644....., Questions I would like to know how the BLOB is actually converted to the above ...
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Similar function NOWAIT in MySQL

Select for update nowait doesn't work in MySQL 5x (innodb). Is there any function like NOWAIT in MySQL?
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1answer
2k views

My master to slave replication stopped and is showing this error when I use SHOW SLAVE STATUS;

My master to slave replication stopped and is showing this error when I use SHOW SLAVE STATUS; | Waiting for master to send event | 172.16.10.37 | repl | 3306 | 60 | mysql-bin.000256 | ...
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1answer
867 views

Find which numbers in [1, 161] are not in the result set?

How to find which two number in [1, 161] is not in the result set? Can I find this two numbers using sql command? mysql> select blog_id from wp_blogs; ... | 149 | | 150 | | 151 | | ...
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1answer
4k views

execute() vs executeQuery() in MySQL Connector C++

With MySQL Connector C++, I can use the sql::Statement::execute() function if I am going to modify the database (INSERT, UPDATE, DELETE, MERGE), or the sql::Statement::executeQuery() function if I am ...
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1answer
2k views

Print table documentation with comments?

I have a MySQL database, and I have used MySQL Workbench to insert text into the "comment" fields of many of the columns and tables; the plan was to have the documentation stored in the database. ...
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1answer
130 views

Is MySQL replication suitable for a Write Mostly application?

I'm considering adding another server to my one-server setup application with 600GB MySQL DB. The db and the apache are both running from the same server. In order to avoid backup downtime and improve ...
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2answers
562 views

mysql myisamchk vs mysqlcheck

We have a mysql database running version 5.0. Every month we shutdown the database for maintenance. We run a myisamchk on the tables to fix data fragmentation, and this takes down the system for up to ...
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1answer
2k views

How do I perform a UNION query on a dynamic list of tables?

My database has an unknown amount of tables, named with the same prefix followed by a random string: _ct_<random_string>. Each of these tables has the same data structure. I also have another ...
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1answer
8k views

How To Optimize and Repair InnoDB tables? ALTER and OPTIMIZE table failed

I just switched my Wordpress databases to use the InnoDB engine. When using MyISAM, I used to run Optimize and Repair table. However, with InnoDB, these don't work. I manually ran OPTIMIZE TABLE ...
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1answer
4k views

How do I reduce the database size on AWS RDS MySQL?

I have an RDS MySQL database on Amazon Web Services. I want to reduce the size of the database in the control panel in order to save money. Q: How do I make it smaller? Their site says you have to ...
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938 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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3answers
10k views

Resolving issue with mysql.proc after upgrading MySQL from 5.0.* to 5.1.*

Like many others, we upgraded our instance of MySQL from 5.0.* to 5.1.49. Since then, we've been running into an error that repeats itself when we perform certain actions: Attempting to view or run ...
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2answers
4k views

How does one change the default socket used by mysqladmin?

How does one change the default socket used by mysqladmin? I don't see a section for [mysqladmin] in /etc/my.cnf. It tries by default to connect to /tmp/mysql.sock, however, this is not the socket ...
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186 views

What MySQL storage engine should I choose?

I have a database for my catalog webpage. Some tables are about 3GB with millions of rows. What engine should I choose for my database, InnoDB or MyISAM? There will only be about 1,000 new records ...
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58 views

Give privilege to new created databases in MySQL

I have user "U" who I want to give him full access to all the existing databases except "db1". I want him to only have select privilege for that db. What I did is I gave "U" all permissions for each ...
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1answer
2k views

How are multiple indexes used in a query by MySQL?

Imagine a table where there are separate indexes on columns a and b. The query runs somewhat like this: SELECT col1, col2 FROM `table` WHERE a = 'value_1 AND b = 'value_2'; Now, does this query ...
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1answer
2k views

change encoding of database from latin1_swedish_ci to utf8

I have an huge database in latin1_swedish_ci. Now i need to convert all data to utf8 collation. My question is about the consistency of the information. When I do this change it is possible corrupt ...
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1answer
207 views

Mobile Phone & Tariffs

I have designed database tables of Mobile Phones & Tariffs. It should support multiple mobile networks, sale type and the related affiliate. Points (for operators) are vary depending on the ...
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1answer
249 views

What logical structure is used for storing rows in Oracle?

From the logical data separation point, there are tablespaces that consist of segments that consist of extend that consist of oracle blocks that consist of OS blocks. What logical structure actually ...
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1answer
675 views

Does creating an index on BIT(n) attribute in MySQL make sense?

I am working on a very specific thing and I need to use BIT(n) attributes and efficiently search through them. n is generally not a power of 2. I've seen some mentions on the internet that BIT ...
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1answer
4k views

What should I set max_connections to for MySQL?

I have MySQL 5.1.35 on Linux Centos. The Linux server has 2GB RAM with 14GB of disk space. I have created some web services using the Restlet framework in Java that has 1,000+ users. What should I ...
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2answers
457 views

Is MySQL Clustering a viable option for a DB expecting 5TB of data in 5 years?

We plan to implement MySQL Clustering.The database should support 5 years of data and expected data/year is 1TB. When we created a test enviornment with the DB size as 200GB, NDB Cluster took more ...
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How can I improve the speed of a query on a 20 million+ row table?

I have a query that is used for getting internet traffic statistics of certain IP addresses. There are separate IP address fields for hosts and blocks of IPs called assignments. The data is stored ...
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How to import Timestamp from a CSV file

I am trying to Import a CSV file with a column called timestamp to MySQl to a column with the structure timestamp but all i get are NULLS in the columns is there a way that i can import the timestamp ...
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1answer
248 views

query optimization delete nested query [closed]

Can the following query be optimized ? DELETE FROM COLOR_TAGS WHERE COLOR_PROJECTID = $id AND NoteID IN( SELECT ID FROM note_note WHERE BibID=$bid AND isdel=0);
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1answer
10k views

Why is LIKE more than 4x faster than MATCH…AGAINST on a FULLTEXT index in MySQL?

I'm not getting this. I've got a table with these indexes PRIMARY post_id INDEX topic_id FULLTEXT post_text Table has (only) 346 000 rows. I am trying to perform 2 queries. SELECT ...
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1answer
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MySQL Partitioning: 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 ...
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2answers
13k views

innodb_flush_method=O_DIRECT vs O_DSYNC performance impact on ext3 with LVM disk partition

In one of my production environment, we have two instances running on a RedHat cluster, with one production instance associated with the cluster. We have 125G main memory with 24G InnoDB buffer pool ...
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2answers
4k views

MySQL Workbench copies Schema, but not data, from SQL Server 2008

I need to copy/migrate a database from MSSQL (SQL Server 2008) into MySQL. I am using the MySQL Workbench kit, and work through the process of the Migration. Each respective DB user has full access, ...
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1answer
4k views

When to switch from MyISAM to InnoDB?

We have a MySQL 5.0 server running all tables as MyISAM. We have two slaves that, in the last month, we have upgraded to MySQL 5.5. Their tables are also still MyISAM. My original plan was to upgrade ...
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2answers
724 views

How to resolve the master server shut down/unavailability in mysql with master - slave replication

Let us suppose that we have a master/slave setup and the application is running fine for the time being. All of a sudden the master server suddenly shuts down due to some problem. Now how can I ...
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4answers
4k views

Should I use the Infobright database or is there a better aggregation solution?

We are a MySQL front-end shop and have a system currently logging event data in a highly structured format. Think apache traffic log. We need to be able to aggregate counts of this data (cube) vis a ...
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1answer
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MySQL Innodb: What is the difference between running 'mysqlcheck --optimize --all-database' compared to running 'optimize table' in the mysql client?

Without having to script an 'optimize table' query to do all the databases/tables, we would like to run mysqlcheck --optimize --all-database instead. What are the drawbacks of doing this through ...
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3answers
477 views

query optimization for update nested query IN(SELECT

Can we optimize this? UPDATE TABLE_NOTE SET COL_NOTE_DISPLAY='BLOCK' WHERE COL_NOTE_BIBID = $projectID AND $COL_NOTE_ID IN ( SELECT COL_PILENOTEREL_NOTE_ID FROM TABLE_PILENOTEREL ...
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1answer
719 views

Removing/overwriting sensitive data located in already deleted records in ibdata files

As far as I know, using InnoDB tables with innodb_file_per_table = off does not prevent deleted data from being visible in the ibdata1 file. I know this is by-design, and that I could switch the ...
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3answers
315 views

Database design for changing number of fields

Google Contacts lets you to enter more than one phone number, or email address for a contact. You can add as many as you want. I don't know if there is a limit, other than practical list size. To ...
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383 views

An “unlimited” data model

I need to store an unknown amount of fields. Some are numbers (like IDs, zip codes and times), some are short strings (like names and states), and some are longer strings (such as descriptions). All ...
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1answer
4k views

How to Create Snapshot Backups in MySQL

I've seen a lot of people talking about snapshots backup, even I'm reading a book about mysql but nobody explain the code how to make a snapshots backup. This is what the book says: flush tables ...
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2answers
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Running multiple instances on the same host

I need to set up multiple MySQL instances on the same host for one of our customers. As far as I see I could go with: mysqld_multi MySQL Sandbox This should be a long term solution for an ...
3
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1answer
5k views

Get two weeks of data but group by a period of 7 days

I am looking to run a query that collects the number of results over the last 14 days, this is fairly easy and achieved like so: SELECT COUNT(id) FROM table_name What I'd like to do is then group ...
3
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2answers
712 views

Sorting the Table and getting the position

I am able to sort a table using the following code:SELECT * FROM Persons ORDER BY LastName But I wanted to get the ranking/position of a person using that order. For example when I sort Person table ...