MySQL version 5.5 - please also tag with mysql for search purposes.

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Percona mysqld got signal 11

I've googled and searched stackexchange, but can't find anything relevant to this particular issue (there are other error 11 issues, just not for this as far as I can tell). We have a server that is ...
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Possibilities to speed up InnoDB INSERTs and UPDATEs

My website retains user sessions in an innodb table. This usually works well, but a few hundred times a day, the INSERT and particularly the UPDATE statements run slower. I'm monitoring when, and it ...
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Unknown option '--no-beep'

I installed a new version of MySQL server (previously 5.0, now 5.5) and I copied the data folder in to the new one. Now I should perform mysql_upgrade. I opened the command prompt (server is located ...
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Need suggestions for best way to archive MySQL (InnoDB) tables

Problem: I have two fairly large tables. A 'wall' table for messages between users with 9 million rows at 2 GB and a 'chapter' table at 2 million rows and 18 GB. I want to keep the number of active ...
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Is there a reason/benefit I am not aware of for this kind setup?

I now manage a MySQL database that was designed and created by another. I am confused about a certain setup that the original developer created.. He did not use auto increments for table IDs. ...
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Grant table privileges to a user connecting from any host

I have a user account - let's call it 'wordpress' - that I need to allow to access a few catalog tables in another e-commerce database on the same server. I've configured the user with three host ...
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408 views

SELECT RELEASE_LOCK causing “Mysql has gone away”

During a long running process (90m+), our code calls SELECT RELEASE_LOCK('..');. However it always gives a "Mysql has gone away" error when we do this. We never got to see the return value of the ...
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Is there a (non-binary) MySQL collation that doesn't treat different mathematical symbols as the same character?

I've run into a real headache with MySQL's collations and non-BMP characters (ones with Unicode codepoints above U+FFFF). Basically, given a table and data like: CREATE TABLE `math` ( `id` int(11) ...
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increasing mysql table open cache?

I often read that it is best to increase this variable slowly. Can someone explain why? My status indicates that I should increase it... What is best practice / "slowly"? Thanks!
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how to enable temporal database capability in mysql.?

How to enable the temporal database compatibility in mysql database? Is there any library or a plug-in to enable the temporal upward compatibility? I want to keep the past records whenever a current ...
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Query not using index when it should

I have this query (below) which keeps hitting the table when it should be using the created index. Is there something simple I'm missing here? How can I get it to use the index instead of the table? ...
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Do I need to index a key that I partition by?

I have an InnoDB table of customers, partitioned by KEY, with each partition being one US state. I have an index on phone number, and the performance is great. We also need to SELECT by last name in ...
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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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644 views

MySQL overhead of calling a Stored Procedure

Within Java, we access MySQL (v5.5.40) via JDBC -- a prepare statement, setting parameters then calling the stored procedure. It appears that every execute() has the overhead of 4 meta-calls (per ...
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293 views

Migrating MySQL to new server

We have a MySQL 5.1 instance running on Windows Server 2008 R2 x64 (Server A) replicated to another MySQL 5.1 instance on Windows Server 2003 R2 (Server B). We have a new MySQL 5.5 instance on ...
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Maximum table size for MySQL database server running on Windows (NTFS) Table type InnoDB

I need to design database to store information contained in millions of log files generated by devices on trial on network. I have designed 5 different tables to store log file information. But, as ...
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MySQL varchar(255) limitation & Anomaly

I have defined a column in my MySQL database as : ALTER TABLE `my_table` CHANGE `desc` `desc` VARCHAR( 255 ) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL However, when I enter text ...
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Issue after moving the ib_logfile1 and ib_logfile0 files

I wanted to increase the innodb_log_file_size for better performance. And I increased it from the default value to 256 MB. As usual I got the error saying InnoDB: Error: log file ./ib_logfile0 is of ...
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“Could NOT find Curses” error when installing MySQL from source

I am installing MySQL Server from the source distribution which I downloaded from: http://dev.mysql.com/downloads/mysql/#downloads. I have downloaded the file (mysql-5.5.19.tar.gz). I am using ...
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Large files in wamp\bin\mysql\mysql5.5.24\data directory

I have discovered these files located in the wamp\bin\mysql\mysql5.5.24\data folder on my Windows 2008 server. They are consuming about 22 GB on a 40 GB drive. I am using a LMS called moodle, that ...
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Stress Test to Saturate Memory for MySQL InnoDB

I'm investigating windows 32bit memory problems (the 2G limit) and am after a test which will max out MySQL's memory including InnoDB Buffer Pool, per connection memory and/or any other uses of memory....
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InnoDB insertion faster

I'm a graduate school student researching OLAP with Mondrian OLAP. So I want to insert data into InnoDB (MySQL 5.5) faster at the initial loading. In this environment, the only user is me, so I think ...
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What can cause TRUNCATE TABLE to take a really long time?

I'm running MySQL5.5 with Master/Slave replication (1 master, 2 slaves). I have a process that runs once a week and truncate a specific table. The table is not large and only has a few thousands ...
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How do you tell which host is close to being blocked in MySQL?

I have a two part question: In cases were this error comes up, is there a way to see if a host is close to being blocked? And fire off an alert? PDOException: SQLSTATE[HY000] [1129] Host `hostname` ...
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MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: CentOS 5.9 24gb Ram 8 ...
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Which is more efficient, trigger or PHP code?

My requirement is to move EMR data for a patient to a set of history tables when the patient has been discharged. I proposed to use an after trigger on the table housing the discharge flag, checking ...
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MySQL optimization - year column grouping - using temporary table, filesort

I have a transactions table which is having 600,000 records, I need to list the count for the dashboard on financial year basis. The table used is MyISAM. I tried adding index for the transaction date ...
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What are the limits on the amount of slaves per master?

I currently have a Master with 2 slaves, all running MySql 5.5. What are the limitations on the amount of slaves I can connect to a single master? what parameters should be taken into affect?
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SQL query to compute longest travel time for each id number

I am a novice in SQL and I have a problem as follows. There are two tables TRNSCTN_TAB: CREATE TABLE TRNSCTN_TAB( `transactionId` int , `UniqueId` int , `transactionTimeStamp` varchar(...
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968 views

mysqladmin - u root -p ping is not executing

I am getting the below error in mysql while trying to ping. i am using mysql version 5.5.37-0ubuntu0.12.04.1. when ever i use mysqladmin i am getting the below error. Please suggest how to clear this ...
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Recover the disk space after deleting rows from table

I deleted millions of rows from one of the table with innodb engine. I know that I need to run optimize table to recover the space. But running that will cause lock on the table, which will affect the ...
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Replication error

We have a slave server that has stopped replication due to the following error: Slave SQL: Query caused different errors on master and slave. What could be the cause of this error? And what would ...
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MySQL runs out of memory when importing innodb database

I have a small VPS with 512MB RAM and no swap (can't have any). I am importing a 1.5GB innodb database with mysql -u -p < database.sql Before the operation can finish it says : Lost connection ...
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Online Schema migration in MySQL : When to start?

I'm the tech lead of a Social Media SAAS, where we're currently experiencing a big increase in data amount we're storing in our mySQL-database. We're having a single MySQL db, and besides many ...
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Is my.cnf for mysql 5.5 is suitable and well tuned for below hardware spec?

My Hardware Spec Technology: Ivy Bridge CPU: Intel Xeon E3 1245v2 Intel Smart Cache: 8MB Cores / Threads: 4 / 8 Frequency: 3.4GHz+ / 3.8GHz Turbo Boost RAM: 32 GB DDR3 Hard disk: 2x 2TB SATA3 Raid 1 ...
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Why max_allowed_packet is larger in mysqldump than mysqld in my.cnf?

If you look at the sample config such as /usr/share/mysql/my-large.cnf, you will find.. [mysqld] max_allowed_packet = 1M [mysqldump] max_allowed_packet = 16M What is the point? Because when you ...
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Slow insert performance in mysql innodb table for solr indexing

I have a Slave server (MySQL 5.5) having innodb tables. This server is being used for SOLR indexing. Few procedures used to fill 12 million data into 9 tables. The insertion speed is too slow. ...
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Is this substring_index behaviour documented or a bug?

mysql> show variables like 'version'; +---------------+-------------------------+ | Variable_name | Value | +---------------+-------------------------+ | version | 5.5.38-...
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Is there a rule of thumb regarding the size and number of a buffer pool instances?

I know the consensus seems to be approximately 75% of ram should be dedicated to the buffer pool. But, I'm more interested in the optimal number of buffer pool instances. What are some things to ...
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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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Problem in Fetching Result set in Desired Format

I have 2 tables having the following columns Person ------ person_id, first_name, middle_name, last_name Items ----- person_item_id, person_id, item_type, status, ordered_date The query is ...
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753 views

How to Update same table on deletion in MYSQL?

In my Database I have a table: Employee with recursive association, an employee can be boss of other employee. Following is query I used to create table: CREATE TABLE IF NOT EXISTS `Employee` (...
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1answer
769 views

How to removing or reduce the size of redo logs in MySQL cluster

Can anybody tell me that how can we reduce the redo log file size or can we remove the redo log file size in MySQL Cluster and also what will be the impact of it on performance of cluster.Also can we ...
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1answer
295 views

MySQL Write performance bottleneck

We are trying to diagnose a MySQL Bottleneck, specifically for data writes. Basically, we have a single process that picks files from a folder and load into a MySQL table X using LOAD DATA CONCURRENT ...
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277 views

Subtract time difference between two columns in a table

Problem: How can I subtract the TIMEDIFF between two sensors (sensor 1 and sensor 2 in the example below) and return the the value in mili seconds? How do I get with the resolution of milliseconds? ...
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Setting up MySQL Cluster on Two Systems

I am attempting to setup a MySQL Cluster. I have the folllowing setup one management node two data nodes another machine on which two more nodes reside Below is the config.ini file: [ndbd ...
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Combine individual sensor values into an overall value with correction factors

For a school project, we are trying to calculate (corrected) Ozone values based on a combination of 5 sensors (3x O3, 1x temp, 1x humidity). We are using MySQL and PHP for the rest of the project. ...
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734 views

Stuck in “query end” status every 5 minutes

I'm sick of seeing data in the slow query log, so I decided to check out what the fuss was all about. An UPDATE query that is running up to tens of times per second is sometimes really slow. Here is ...
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739 views

Finding differences between a master and slave when pt-table-sync fails

I have a table that's showing some differences on a master and slave according to pt-table-checksum (PTC). I've found some verifying differences beyond that. Certain tables in the mix have composite ...
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Why is loading data into MySQL cluster taking so long?

I have a mysql-5.5.22 ndb-7.2.6 cluster 64bit running on Centos 6 with each node installed on the same Citrix Xen Server communicating via a virtual private network. Each node has 4GB of RAM, 4 vCPUs ...