MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.

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30 views

Is it possible to find the user whose aggregated score reaches X value first?

Given this sample fiddle containing sales value and date for two users: http://sqlfiddle.com/#!2/8148be/3 How can I find the first user who has reached a total saleValue of 30 since the beginning of ...
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3answers
205 views

Will redirecting queries to dev/null warm up indexes?

I'm trying to warm up the buffer pool. Will running a query and re-directing the output to /dev/null suffice? e.g. mysql -u username -p -e "select id from tbl where 1=1" > /tmp/results.txt Thanks
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1answer
2k views

column auto updated after 24 hours in mysql

i have a table T1 with column : Name State time mon 1 2014-01-09 11:23:00 tue 0 2014-01-07 14:40:00 wed 2 2014-01-08 09:23:00 thu ...
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1answer
52 views

How are these two user drops different?

Other than the obvious, what is the difference between: drop user user_01@host01; and drop user 'user_01'@'host01'; In a sample test, they both achieved the same result. From Account Names docs ...
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1answer
608 views

How to set unique columns combination

see this table: CREATE TABLE IF NOT EXISTS `default_messages_users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `message_id` int(11) NOT NULL, `owner_user_id` int(11) NOT NULL, `to_user_id` ...
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2answers
210 views

Is possible to optimize this query or it's already optimized?

I've three tables: default_users, default_profiles, default_friend. This are the SQL for each one: -- -- Table structure for table `default_users` -- CREATE TABLE IF NOT EXISTS `default_users` ( ...
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1answer
825 views

Change root password of mysql database

This could be a Rookie problem , but it seems that i am not able to solve it. I have MySQL server installed on my windows machine(MySQL 5.5) under the Admin username root. Some How i lost the ...
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1answer
728 views

when will Innodb support activation of triggers on cascade foreign key? [closed]

The Manual says: http://dev.mysql.com/doc/refman/5.6/en/innodb-restrictions.html Currently, cascaded foreign key actions do not activate triggers. Any Idea when will this be implemented. Is ...
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3answers
253 views

getting error while starting memecached service with ndb engine

i am installed memcached library by following the steps in the internet. now there is a binary file created in bin folder of mysql now i exicuting the command memcached i am getting error like this ...
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1answer
4k views

MYSQL query to find records between two date range

I am working in a web application using PHP and MySQL. I have two tables Employee employee_id email_id 3 tl1@jasmine.com 4 agent1@jasmine.com 5 ...
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1answer
120 views

MySQL Latest Deadlock Explanation

Can someone explain this deadlock to me? It seems as if there are 2 inserts happening within milliseconds of each other with the same Primary Key. I'm not sure how this can cause a deadlock. At most a ...
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2answers
73 views

MySQL query performance question

I have a MySQL database where I would like to return results based on multiple rows. id | key | value | selector --------------------------------------------------------- 1 | username ...
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1answer
747 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, ...
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1answer
403 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 ...
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2answers
6k views

How to outer join multiple tables to retrieve uncommon records

I'm trying to do an outer join in MySQL to identify records not common to 3 tables. Here's my current effort http://sqlfiddle.com/#!2/02b92/30 I'm trying to retrieve the records not common to all ...
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1answer
212 views

database design for dynamic menu bar [closed]

I am trying to create a menu bar which will load dynamically on user log in, based on the user roles. Say if the user is an admin he can see all the items listed under the header and if a user is a ...
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2answers
86 views

Are relay logs necessary for replication?

I'm trying to understand when/where using relay log is beneficial. According the documentation, mysql captures and writes events from the master's binary log as the result of the I/O thread. Then, the ...
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2answers
299 views

Nested query efficiency in MySQL

I have a table with several attributes like this: id id2 attribute -------------------------------- 1 100 blue 2 100 red 3 100 green 4 100 white 5 102 blue 6 102 green 7 102 ...
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1answer
204 views

How to store temp tables in memory during table “optimize”?

When optimizing tables, SHOW PROCESSLIST lists it as "copying to tmp table". I'm trying to ensure the copy takes place in memory to speed up the process. I've tried adjusting the tmp_table_size to ...
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2answers
321 views

avoiding unique key collisions across tables

This might be related to the idea of data warehousing, but i'm not sure, though it is extreme theory. We have a table where records get written to first, let's call it tbl_recording which looks like: ...
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1answer
95 views

How and where do I upload a mysql database?

I am new to Ubuntu (server edition) and mysql. How do I upload (import) an existing database with a MYSQL or (mysql.zip) extension that was downloaded from a web host (cPanel?) I do not have any of ...
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2answers
76 views

need help in Query optimization

I need help in query optimization,I am having table with structure Create Table: CREATE TABLE `ip_country_mapping` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `cron` bigint(20) NOT NULL, ...
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2answers
126 views

Need some support on MySQL Query

I have a query SELECT leads.id, sfav.id is_favorite FROM leads INNER JOIN teams tst ON tst.team_set_id = leads.team_set_id INNER JOIN members members ON tst.team_id = ...
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1answer
2k views

ERROR 13 (HY000) When Creating Database

I'm trying to create a database and when I type in CREATE DATABASE epik; I get the error ERROR 13 (HY000): Can't get stat of './epik' (Errcode: 13) I am running kubuntu 13.04 with mysql 5.5.31.
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1answer
453 views

Unable to use mysql_upgrade:

I updated mysql recently and found problem related to privileges and backup. When I am using mysql_upgrade command it says- mysqlcheck: Got error: 1064: You have an error in your SQL syntax; check ...
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2answers
378 views

How to avoid lagging when enabling log-slave-updates?

Master: 48GB RAM 16-core my.cnf: https://clbin.com/hlkUo Slave: 64GB RAM 24-core my.cnf: https://clbin.com/viLm0 Both are running 5.5.28. For the incremental backup purpose, I need to enable ...
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1answer
2k views

Should I disable triggers, timestamps in a slave in mysql?

We're using MySQL. We have a master that eventually will have 2 slaves. There are triggers in the db that execute when data changes in certain tables. I am wondering whether to disable the triggers in ...
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1answer
2k views

How to Log IP Address for Inbound Connections in MySQL

Is there a way in MySQL 5.5 (on Redhat 6.x) to log the IP address from where a particular query has been run? And have that appear in the general log or even relay and bin logs? I am trying to track ...
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3answers
73 views

Contains statement Query

I need to check the string with the column if the column contains that string or not. example:String 'how to make pizza' and the column if has 'pizza' i need to fetch that.. like SELECT * FROM ...
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1answer
918 views

Query to take partial backup in MYSQL

I tried to take full backup in mysql using enterprise backup by using the command mysqlbackup -u root -p --backup-dir=g:\full_bck backup But I could not take backup of a single database , I ...
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1answer
3k views

How to COUNT number of rows with LIMIT?

I want to catch X rows, thus, I set LIMIT X; but how can I simultaneously count the total number of rows too? Currently, I use two separate queries to do so as SELECT COUNT(*) FROM col WHERE CLAUSE ...
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1answer
317 views

How can I change the timezone in MySQL?

In a MySQL DB, I have two varchar fields. One is for date and one is for time. I need to change the time from CST to GMT. In MySQL how do we convert the combination of these date and time fields from ...
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2answers
194 views

Is there a way to get slow-query-log-like profiling information on a single query?

Specifically, I'm looking for this information: # Query_time: 0.011922 Lock_time: 0.000088 Rows_sent: 107 Rows_examined: 663 Rows_affected: 0 Rows_read: 107 # Bytes_sent: 4152 Tmp_tables: 3 ...
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1answer
801 views

How can I trigger this stored procedure on insert?

I have a table of error messages to which errors will be inserted. I also have a table defining interactions between errors. For example, when a "Power Restored" error occurs, it clears any previous ...
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2answers
59 views

mysql master slave replication scenario

We are creating a new mysql slave, but for dump we are taking from a backup server which is a slave of current master. Now to enable replication we want to connect it with the master so should I take ...
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1answer
44 views

Purge mysql log bins older than two weeks automatically

I have to manually write purge binary logs bin to "mysql-bin.somenumbers" ; Once in a while, I need to reduce the spaces that binlogs are taking on my web server. Is it possible to purge binary ...
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1answer
25 views

Failing to get multiple values using join

I have below scenario: create table t1 (id int, title varchar(20), description varchar(20)); create table t2 (id int, info1 varchar(20), info2 varchar(20)); create table t3 (id1 int ...
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1answer
62 views

Simple query hangs on a specific column condition

I have two servers, and I a dumped the database of the first to restore it on the second. Everything works great, except that on the second server, I can't do any selection based on a specific column ...
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2answers
127 views

Monthly report by time [closed]

I work in a parking company. We need a report of monthly vehicle exits by time. select hour(datetimeout) as 'dateout',count(*) from to_leaveveh where datetimeout between '2014-09-01' and ...
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2answers
624 views

Using MySQL/PHP PDO, is there a 'simulate' or dry run option?

Does MySQL (or, ideally, PHP PDO) have some way of simulating transactions without actually committing them? (Can I get MySQL or PDO to act as if data is inserted/deleted/updated, without actually ...
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1answer
856 views

Group by age range and gender with aggregation function on some columns

In Mysql, I have a patient table with id, birth_year and gender. Next table is transactions in which I have id, patient_id [FK from patient] and checkup_date. I need to select rows such that I get ...
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2answers
79 views

MySQL: How to sync on demand beetwen two database in the same server

I'll like to know if it's possible to have a systeme on synchronisation beetween two database in the same server. I have a production database in my server , i want a dev database (same database with ...
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3answers
576 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 ...
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1answer
464 views

unable to import the file

Gone through the below link also but i am unable to import CSV file in mysql. Even i had tried by using > LOAD DATA LOCAL INFILE but same error persisting. Please help me in this. queries i tried had ...
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2answers
202 views

getting one day timestamp in mysql

Please consider the following stored procedure I have: ORIGINAL Stored Procedure: -- -------------------------------------------------------------------------------- -- Routine DDL -- Note: comments ...
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1answer
297 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 ...
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1answer
112 views

Migrating MyISAM tables from 5.5 => 5.6

I was wondering if anyone had any pointers on migrating MyIASM tables from mysql 5.5 to 5.6, specifically using Percona builds, via an rsync? Is this safe? I know we need to do a full ...
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1answer
201 views

What is the difference between uniqe index/unique/unique key/unique constraint keywords?

I am using mysql 5.5.16 What is the difference between the following DDL statements? 1) create table sql_query ( id int not null , query_text varchar(21826) not null , query_md5 ...
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2answers
904 views

Can I disable an account in mysql after x failed login attempts?

The question is in the title. I would like to disable accounts after x failed login attempts. Is it possible? Thank you
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2answers
147 views

Indexes slowing Insertions(Can't use Explain Insert to Analyse)

I have a MySQL database, I am parsing files from a log and inputting it inside. So far including a simple 4MB file in the database could take me about 4 minutes to insert ! and i have about 10,000 ...