MySQL : Open-Source, Relational Database Management System

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DB Design: Is it ok to have 40+ columns in a MySQL DB

I am currently re-designing some of DB's for a project. There is one DB in particular that is giving me a little of a headache. The idea is that for every client_id and date (client_id + date would be ...
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13 views

Increase performance WITHOUT adding indexes

I'm having a rather large table (350MB, 1.3M rows) and there are dozens of queries arriving at this table every second. Most queries are super-fast thanks to indexes - but some others aren't. ...
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8 views

Sysbench insert data between a given range

I was trying to insert 1000000 records of data into 1000 tables in sysbench. But after installing about 278, sybench just crashed with the following error: FATAL: failed to execute function ...
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9 views

Are ZRM (Zmanda Recovery Manager) incremental backups reliable?

I had an issue while restoring incremental backups and I'm wondering if they are reliable. I'm making weekly full backups and daily incremental backups and I needed to restore a single database after ...
2
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1answer
10 views

What is the Best way to set Disaster recovery setup for percona Xtra DB Cluster?

We do have a Percona XtraDB Cluster(Master-Master-Master) setup in one country. Now we want to setup a disaster recovery setup in some other country. Please provide us the best possible ways to do ...
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31 views

Select these if this, or select these…

Here is my problem: organization_category.id can be either 1,2. With organization_category.id = 1, then the organization_type.id can be 0,1,2, or 3. With organization_category.id = 2, then the ...
0
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1answer
14 views

Select all results from two independent tables

I have two tables: Comments -------- id comment_content time_stamp Activities ----------- id activity_content time_stamp And I would like to combine the results from both, ordered by their ...
1
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1answer
12 views

How to Paginate a MySql Ranking Query

I have the following ranking query working fine with a limit of 25 records per page, it shows 1st - 25th for the first 25 records, but when i go to the next page, the rank stays the same 1st - 25th ...
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3answers
31 views

MySQL select with between optimization

I got issues with some geo IP query. So basically here is create code of table: CREATE TABLE `geo_ip_city` ( `id` INT(5) UNSIGNED NOT NULL AUTO_INCREMENT, `begin` BIGINT(20) NOT NULL DEFAULT ...
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10 views

upload updated details in excel to mysql database

I have a batch file which updates the excel file by adding the latest values to it. The details are already there in the MySQL as a table. Once the details are updated. For eg after the end of day ...
0
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1answer
19 views

How to update Large table in MYSQL

I want to update a large number of rows (more than 80k) from an external data source (from file) into an existing mysql table. This database is InnoDB. Database structure: CREATE TABLE IF NOT EXISTS ...
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1answer
19 views

Newly created user has rights on MySQL database

I use the root to create a new user, like this: I have no more operations on it. Then I use this user to log in: I try to do some operations like this: Here "test" is a database which I created ...
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13 views

Unexpected slow queries at random times

I have a moderate service, serving at most 100~ users at the same time. Mariadb slow log is open, and I occasionally see reports of slow running queries such as: # Time: 141123 19:48:38 # User@Host: ...
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Fast select = slow update, slow select = fast update

A query is super-fast when executed as a SELECT (#1), but when I try to UPDATE using the retrieved data, the performance starts to be unpredictable for me. For example, an UPDATE is faster with much ...
0
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1answer
17 views

MySQL rapid Data Replication from multiple Databases

I am a Freelance Web Developer but not a Database Administrator at all except basic Database Operations like DML etc. Today I got a client asking me to develop a Web based application but there is a ...
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1answer
30 views

Unknown column in 'where clause'

I've a query in my php script $result = mysql_query("SELECT State_Id FROM state_master WHERE State_Name='$statename'") or die(mysql_error()); $row=mysql_fetch_assoc($result); return $row['State_Id']; ...
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1answer
29 views

Is a query inside mysql IF clause allowed?

DELIMITER $$ CREATE PROCEDURE `InsertUser`(IN passwd VARCHAR(100), IN userType VARCHAR(20), IN mobileNo VARCHAR(20), IN refId BIGINT(20), IN companyName VARCHAR(100), IN companyMail VARCHAR(200), IN ...
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1answer
28 views

How much space is needed to reclaim space from a table in INNODB

I inherited a MySQL InnoDB table that has approximately 200 GB worth of data, as well as several unneeded indices that amount to approximately 500 GB. I've archived approximately 75 percent of the ...
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2answers
51 views

What's wrong with my SQL statement? [on hold]

I'm trying to execute: create table `certificates`( `id` INT NOT NULL AUTO_INCREMENT, `common_name` VARCHAR(100) NOT NULL, `csr` LONGTEXT NOT NULL, `type` VARCHAR(100) NOT NULL, `certificate` ...
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1answer
20 views

Does a database update force index rebuild regardless of updated field?

With MySQL (InnoDB), I understand that having indexes slow down UPDATE queries. I would like to know if this happens regardless of what fields are updated. For example, if I have a table with 20 ...
1
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1answer
50 views

How to get the SUM between dates in a WHERE clause?

I'm trying to get the SUM between each date in the WHERE clause of the following query, not the cummulative sum, but the sum for the period in between the dates. For example: Query: SELECT ...
2
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2answers
27 views

Joining two Mysql VIEWs takes a very long time

I have a textbox (for which I used jQuery auto-completion) in my PHP form where user can insert an actor/actress name and then by clicking "Search" button, a new window is opened showing list of ...
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1answer
58 views

How to combine two queries? [on hold]

I can't explain this very well except by spelling it out. I start a query on ID, and from there I can get TITLE, DATE, and REGNUMBER. The problem is I also want to get 'where,' which is also stored ...
2
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1answer
18 views

MySQL table indexes change location

Is it possible to move the MySQL Table indexes to another location rather than "datadir" ? for example a ssd drive or memory partition ?
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2answers
43 views

How can I simplify this UNION?

Here's the case - I have the following query: SELECT DISTINCT post_id FROM ( ( SELECT DISTINCT rp.post_id, pm.meta_value AS premiere_date FROM wp_related_people AS rp JOIN ...
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1answer
30 views

MySQL no query cache hits

My database have been up and running for a while with query cache enabled, but there are 0 hits. I have tried to check the settings but I am not sure what the problem is. Using InnoDB. mysql> SHOW ...
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2answers
26 views

Outer Joins to find records with no matching associated entries

I'm trying to find all foo records which do not have any bar records that match a given criteria. create table foo ( id integer ); create table bar ( foo_id integer, name varchar(255) ); ...
0
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1answer
19 views

WordPress MySQL writes during “Flush Tables With Read Lock” are rejected instead of being queued

I'm running into an odd issue when setting MySQL into a brief read-only mode for backup. Reads continue fine during that "read only" minute, but writes are just rejected instead of being queued to ...
1
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1answer
37 views

Taking the difference in timestamps between successive entries

This is my first foray into DBA.stackexchange, so I'll say up front: this is a query optimization question. If this is not an appropriate question for DBA, let me know and I'll skulk away quietly... ...
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2answers
93 views
+50

Is this update, select combination query thread safe?

I have a table called seats, which has a schema like this id,taken For each user, I take a random untaken id and assign to that user, here for simplicity say, I make taken =1. The query I am ...
2
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3answers
55 views

Running two DELETE statements causes a syntax error

DELETE `member` FROM `member` WHERE `member`.`type_id` = 1; DELETE `subscriptions` FROM `subscriptions` WHERE `subscriptions`.`type_id` = 1; Table: subscriptions ...
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13 views

MySQL Remote Database Failover: Need Advice

I run a network of sites all on 1 server. To improve performance, I'm (finally) moving the MySQL database to a remote machine. I'd love anyone's advice on how to appropriately approach failover. ...
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22 views

Migrate from SQLite to MySQL (then back)

For various reasons, I must use a SQLite database with a local application. However, I wrote a Flask app that enables users to more easily classify items in the database, and it runs very slow on ...
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23 views

MySQL 5.6.19a InnoDB Concurrent Insert

I've looked through most of the threads on this topic but still had question I was hoping someone would be gracious enough to help with. I am seeing low CPU usage and write latency but transaction ...
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0answers
21 views

Need advice on optimizing database on a recurring basis

I have a search engine with approx 3.5 million rows in the searchable table. There are many suppliers that feed into the table each day, so primary keys are constantly being removed and added and the ...
3
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2answers
410 views

Can anybody tell me what's wrong with this query?

CREATE PROCEDURE Click( in ipaddress varchar(45)) BEGIN DECLARE ex int; SELECT COUNT(*) INTO ex FROM clickactivity WHERE IP = ipaddress; IF ex = 0 THEN INSERT INTO clickactivity (IP, ...
0
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1answer
45 views

MySQL-How to find that value in a column is subset with all other values in same column multiple time

I have a table named as Team where table contain 3 column (ID,Team,Task). Its datatypes are (INT,VARCHAR(255),INT). Below you will find a sample table where I would like to perform the query on column ...
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1answer
43 views

Similar hardware, Same DBconfiguration and Database but different status variables result between Windows and Linux server

I have two database servers - one is Windows - 2008 and another is RHEL5 with similar hardware configuration. Both OS are 64 bit. MySQL 5.1.58 community edition is installed on Windows servers while ...
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2answers
48 views

Companies and addresses MySQL

I've got a database with 2 tables. companies addresses These are my tables. Adresses adress_id adress_adress adress_adressnumber adress_zipcode adress_city adress_postbus adress_country ...
0
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1answer
27 views

schema for mysql database with 30million rows

We am building a SaaS backend for restaurants. We integrate directly with POS, so each POS keeps sending customer orders that we store in a following table in mysql. CREATE TABLE name ( `id` ...
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0answers
24 views

Handling this multi-threading scenario in the database?

I am working on sample bus ticket booking application,in I am facing these two multi-threading scenarios. Scenario 1 1: Let's say there are two users, they both pick a particular seat and submit ...
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39 views

select sequential rows

How would I go about selecting a sequence of rows. Where every row in the sequence: Must only be 1 day apart ~ Thereby the whole sequence of rows must have sequential dates Must have a count higher ...
2
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3answers
53 views

Bulk Delete for Large Table in MySQL

I have a Notification table contains about 100 million rows host in Amazon RDS with 1000 IOPS, and I want to delete those rows older than one month. If I do DELETE FROM NOTIFICATION WHERE CreatedAt ...
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Reset relay files on lagging slave after MySQL crash signal 11?

MySQL crashed on this slave server with signal 11: Error reading packet from server: Lost connection to MySQL server during query ( server_errno=2013) Slave I/O: Replication event checksum ...
0
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2answers
39 views

MySQL any way to import a huge (32 GB) sql dump faster?

I have this huge 32 GB sql dump that I need to import into MySQL. I haven't had to import such a huge sql dump before. I did the usual: mysql -uroot dbname < dbname.sql It is taking too long. ...
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1answer
23 views

Is there a way to prevent special characters on schema objects?

I would like to prevent the creation of objects with spaces or special characters. Is there a way to allow only letters, numbers, and the underscore? Thanks!
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How to determine if open_table_cache is set properly?

Does anyone know what this really means? (from MySQL docs) You can determine whether your table cache is too small by checking the mysqld status variable Opened_tables, which indicates the ...
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1answer
35 views

Get a teams Rank based their xp [on hold]

Table is called teams, need to get the following columns... name, wins, losses, percentage, level, xp WHERE console = 3 AND game = 23 AND laddertype = 1 I'm in need of a Rank column to be included ...
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1answer
21 views

CONCAT() between different alphabet echoes out '&' ampersand

I want to concatenate different alphabet strings and get a weird latin encoding with ampersands after the sixth greek character (I want to concatenate greek and english alphabet strings). Lets say I ...
0
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1answer
23 views

MySQL Circular replication with fail over

I have 3 MySQL servers which is running with circular replication. Server A version - 5.5 Server B version - 5.6.21 Server C version - 5.6.21 Master Server FOR Slave Server C ...