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

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260 views

Use string functions and arithmetic calculations in SQL query or by programming language?

I need heavy arithmetic and string functions for processing the data captured from mysql database. Which is preferred: mysql functions or programming language (e.g., PHP)? $result = ...
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3answers
295 views

What happens when we take a timediff between timestamp and datetime

Say I have following table in mysql (5.5+): CREATE TABLE IF NOT EXISTS `test` ( `id` int(11) NOT NULL, `x_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, ...
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1answer
49 views

How can I efficiently search for all records from a given month, or a given year?

We have a couple queries that involve datetime fields. In particular, we are checking for things like SELECT field1, field2, ..., field20 FROM table WHERE MONTH(startDate) == 1 SELECT field1, field2, ...
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2answers
99 views

Is column order reliable in UPDATE?

Can we reply on the order of columns in an UPDATE? SET @x = 0 UPDATE table1 SET col1=IF(col1 IS NULL, NULL, @x:=@x+col1), col2=IF(col2 IS NULL, NULL, @x:=@x+col2), col3=IF(col3 IS NULL, NULL, @x:=0) ...
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1answer
469 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
289 views

How to use LOW_PRIORITY for heavy queries?

I have scheduled heavy UPDATE queries at administrator level, and since they are heavy UPDATEs with multiple JOINs, consume a huge amount of resources. I do not want them to stop end users from ...
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1answer
73 views

Query result set

I've 1 query written in our legacy system. (using MySQL 5.5) Now, with growing data - the below mentioned query taking huge time. In our system, we've somewhat 2,000,000,000 (2 billion rows) approx ...
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2answers
70 views

Grant access on a database to all users

I have a global database, as I all users should have access to it. Is it possible to grant permission on a database to all users? something like GRANT ALL ON my_database.* TO *@localhost; Even (for ...
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1answer
1k views

MYSQL - Problem with foreign keys on same table

In Mysql 5.5, I have a table, in which I store some informations about "events".. In order to have a chronological order, I made two columns that reference to the previous and to the next event. So I ...
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0answers
94 views

Cannot find /etc/init.d file in opensolaris

While installing MySQL , I noticed a point, I mean to start the MySQL server manually , use the command cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysql The error shown is : cp: ...
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1answer
60 views

Few Insert queries rollbacked due to system crash

Well, this problem occured to me first time. Yesterday, one of our mysql system server crashed and when it restarted last few inserts were completely rollbacked. I am sure that they were proper ...
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2answers
95 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 ...
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2answers
104 views

Uninstalling MySQL on Solaris

I have installed MySQL 5.5.31 in Opensolaris. When I tried starting the MySQL server, it says bash: mysql: command not found So, I decided to uninstall the whole lot and try doing again. But I could ...
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1answer
198 views

char vs varchar in mysql

I was reading the book MySQL high performance, it has mentioned that : CHAR is also better than VARCHAR for data that’s changed frequently, because a fixed-length row is not prone to ...
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0answers
38 views

I can't get MySQL server to stop running

The output from MySQL Workbench when I try to stop it is: Executing '/usr/local/mysql/support-files/mysql.server stop' 2013-12-23 21:08:29 - Stop server: ERROR! MySQL server PID file could not ...
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0answers
123 views

MySQL Load Avg High — CPU bound or IO Bound or Memory Issues

We are using MySQL 5.5 and the database is approximately 10TB. The load avg is constantly high during day time. Following are the configurations and a snap shot of a 'top' command. I wanted ...
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1answer
204 views

MySQL with high CPU and memory usage

here we have a VPS with 3.2GHz quadcore processor with 2GB of RAM and 4GB of SWAP which need to work with a high intensive legacy system (read: bad coded). The main problem is that the CPU (~80 - ...
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2answers
93 views

Query only for the first n results of like

What I'm trying to accomplish is a huge speedup (read: incremental results) when searching a database with a like operator which is kind of a last resort, if everything else already failed, to come up ...
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1answer
1k views

Query State hangs on sending data

For some reason, the query state hangs on "Sending Data" (using show processlist;) and I have no idea why. This is the table creating script: CREATE TABLE IF NOT EXISTS `esp_game` ( `gameID` ...
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2answers
466 views

How to SELECT rows with time duration stored in varchar column?

There is a column in table defined like this : duration varchar(10) It has value for duration of a MP3 file stored in it like : 52:19 (Minutes : Seconds) How can I create a SQL query, for ...
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1answer
68 views

Installing MySQL in Solaris

I am trying to install MySQL 5.5 on Solaris 10. I executed the code useradd -r -g mysql mysql where a group called mysql is already created using groupadd command. I get the following error : UX: ...
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2answers
57 views

Mysql 5.5.25 must be restarted to connect

We have MySQL v5.5.25 running on Windows Server 2008 R2. Occasionally people are unable to connect, and the only way we have found to fix this is to restart the mysql service. This happens every 2-3 ...
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2answers
2k views

What is the meaning of tinyint(N)?

When we use an argument length with numerical data types, as far as I know this specifies the display width. I tried the following: mysql> create table boolean_test (var1 boolean, var2 tinyint); ...
2
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1answer
404 views

How to modify `proxies_priv` in MySQL

I recently received a warning from MySQL that stated: [Warning] 'proxies_priv' entry '@ root@serverdomain' ignored in --skip-name-resolve mode. I looked in mysql.proxies_priv and there is ...
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2answers
98 views

How to store logs correctly?

(This is somewhat a follow up on my last question) I am using MySQL 5.5 with innodb. My Log table consists of two columns. One for user number, and the other for a string consisting of IP, request ...
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0answers
216 views

What is the ideal connection pool size for RDS MYSQL?

I have a tomcat server hosting REST APIs. It is connected to a MySQL (RDS Instance) server on the backend. A majority of the operations are write operations (Around 75%). I'm using the Tomcat's ...
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1answer
4k views

InnoDB: Error: Table “mysql”.“innodb_table_stats” not found after upgrade to mysql 5.6

I upgraded to mysql 5.6 from 5.5, and now my logs are littered with such messages on startup I found a possible solution here, but it does not seem official. ...
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2answers
292 views

Warning before issuing delete/update command in mysql/oracle , then executes

Is there any utility , function either in mysql /oracle that if i issue some delete/update command wrongly , a message must prompt at command_line* (if possible in ubuntu) asking whether "you sure to ...
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1answer
89 views

addition in datetime column during insertion in mysql

i have a table with below 5 columns..timestamp is data type for timedate related column : Region event_time start_time mid_time end_time India 2013-11-03 13:00:00 America ...
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1answer
64 views

MySQL geospatial query optimisation suggestions

I am new to DB Administration. Trying to sort out this query which is the heart of our application. I am searching google on similar questions, but would like an experts opinion on my particular ...
3
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1answer
112 views

How to upgrade MySQL (5.5) production DB to 5.6 with minimal downtime

Our existing Database size around 200GB. We want to use consistent, parallel backups methods. For testing, I migrated my Development DB from 5.5 to 5.6 by running mysqldump with option ...
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1answer
573 views

Timeout on ALTER TABLE table ENGINE=InnoDB - is table still converted?

I'm converting tables in an old MYISAM database to InnoDB to increase robustness in case of power loss etc. I'm using Mysql 5.5.x Before doing the production system, I am doing a trial run on a copy ...
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1answer
276 views

wordpress table is crashed and should be repaired

I run a wordprees website and use a managed VPS server with cPanel/WHM. Got bellow error log and check the table. I repaired the table with repair table command from phpmyadmin. But this problem occur ...
0
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1answer
163 views

Data Analysis with MongoDB or MySQL

I have a need for processing some data in order to come up with some statistic. This is the scenario: Each user can answer several questions from the question list. They pick their answers from a ...
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3answers
540 views

Converting live MyISAM table to InnoDB

I have a table that tracks web traffic. The table is constantly written and read from. Since table is pretty big in size I have to make sure the application will not "freeze" in the process of ...
0
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1answer
305 views

Datetime Difference in MySQL when format is Varchar

I have two columns in a table: STOP and START, of type varchar. I want to have the difference between both columns, and I'm using : SELECT DATEDIFF(stop, start) AS difference from T1; It is ...
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1answer
1k views

MySQL - Server collation utf8_unicode_ci vs table collation utf8_bin: compatibility and performance

I'm not sure whether this belongs to SE DBA, but it sounds more logical ... Our MySQL 5.5.32 on Ubuntu 12.04 64 uses utf8_unicode_ci for the Server collation and some tables, like phpBB3, uses ...
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2answers
711 views

Master slave replication in mysql seconds behind master goes on increasing

In replication at slave end seconds_behind_master goes on increasing. The dump file for upload is of 6.7 gb large, can it be the reason for the lagging of seconds behind master?
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2answers
160 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
125 views

Update the host field in Grant privileges in mysql

I have an existing table and I want to update host part in privileges using Grant command mysql> show grants -> ; ...
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1answer
102 views

Database design [closed]

I have tables college and department. In college, I have serial-number and college-names, In department, i have nos, college-names and department-name. My challenge is that having a repeated ...
0
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1answer
493 views

SQL Query is sometimes slow, sometimes fast

I have two hosts, one with my rails app, one with my MySQL database. Going through my rails Logfile I can see that sometimes queries take much more time than the same query at other times. Think 200ms ...
2
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0answers
94 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 ...
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1answer
204 views

Squeezing Maximum Out Of My Server

I have a dedicated server only built to hold MySQL databases. Currently I have a database that has 173 million records and increasing by 5-15+ million records very day. My question is what and why I ...
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0answers
39 views

Is there any way to set server-wide and schema-wide default row formats for InnoDB tables in MySQL?

Is there a way to set server-wide and database-wide default row formats? Currently it seems that I must specify ROW_FORMAT in CREATE TABLE or ALTER TABLE statements. Am I reading the documentation ...
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0answers
104 views

How to set up a pivot table view?

I have three tables: Entry Manager Employee The Entry table has as date field and a bunch of other fields about the entry including the emp_id. Manager Table has columns: Manager_id ...
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0answers
465 views

Fastest way to perform simple operations on 1 million rows

I have a simple table with more than 1 million rows in an InnoDB MySQL table. Here are the steps that I need to perform on each row: SELECT * FROM tbl where work_done=0 make some data processings ...
0
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1answer
39 views

Migrating database with views trough phpMyAdmin causes error in second host

I'm trying to migrate a database which contains some views and I'm doing trough phpMyAdmin export feature. MySQL version on servers are: Server to migrate: Server version: 5.5.34-0ubuntu0.12.04.1 ...
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0answers
27 views

Anyone know the fix for an older innodb inspection query

This post talked about an information_schema query to give you a nice report of how much percentage wise indexes are fitting into the buffer pool The query looked like > SELECT `schema` ...
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2answers
933 views

Fastest way to change a 600GB table indexed key datatype from INT to BIGINT

I need to change a datatype from INT to BIGINT in a 600GB MySQL table. The column has a unique index. I might be good with unsigned INT, but I assume changing to that or BIGINT will be pretty much ...