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

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2
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1answer
204 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 ...
2
votes
3answers
421 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 ...
0
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0answers
103 views

Configuration help my.cnf Mysql

Is the following my.cnf file OK for a dedicated server with 56GB of RAM (on ubuntu server and 8 processors)? I'm running just one website on the server and there is a high demand on my cpu from ...
1
vote
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 ...
-1
votes
1answer
293 views

Restrict access to rows by usename

In my database i store data of different users (e.g. addresses or invoices) in the corresponding tables. I want to make sure that a logged in user only has access to it's own data in the tables (so ...
1
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0answers
353 views

Lost Connection to mysql server at 'reading authorization packet', system error 0"

OK, this has been bugging me all afternoon now, I have a new MySQL Database '5.5.40-0+wheezy1-log' running on Debian Linux. It is to all extents and purposes a clean install. I have created two ...
0
votes
0answers
776 views

Following mysqltuner suggestions: query_cache_size and join_buffer_size

So I am following the suggestions of mysqltuner, and so far I've had great results, the server is performing well (dedicated VPS running a large Magento eCommerce store) There is only two issues left ...
0
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0answers
79 views

MySQL Crash due to “InnoDB Assertion” after Query

Current setup: Ubuntu 12.04 LTS MySQL 5.5.31 Current Use: Slave - Only ETL queries 64 GB RAM Intel(R) Xeon(R) CPU X5670 @ 2.93GHz - 12 Cores - Hyperthreaded (24 Logical) MySQL Main Settings: ...
0
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0answers
46 views

Last synchronization time between master and slave (replication)

During replication process where a Master is connected with slave. Some times connection between these two goes down. Any options to get the details of the last synchronization time?
0
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0answers
216 views

MySQL “ERROR 1005 (HY000): Can't create table 'foo' (errno: 13)”

Windows Server 2008 MySQL 5.5.39 using the root user with full privileges granted to the DB. I know errno: 13 is a permissions issue. I've seen several answers to this for linux where setting ...
1
vote
1answer
97 views

Immigrate to file-per-table mode in MySQL

I have 20 MySQL databases and in each there are about 20 tables. All the data is saved in a file called ibData1. Now I discovered about the file per table mode but if I change the value in the my.ini ...
1
vote
2answers
352 views

Identifying cause of high I/O

I'm trying to diagnose the bottleneck for high-write I/O activity on a percona master (with replication to a slave). The pattern of behaviour is roughly cyclic and regular: 60 mins of 75-90% ...
0
votes
1answer
300 views

Workaround to avoid read-only table locking during execution of MySql OPTIMIZE command

We need to optimize a large table (on a weekly basis) in order to reclaim disk space, since records are being deleted regularly from the table. The table in question is an InnoDB table and the ...
0
votes
1answer
78 views

Filtering the results of a SELECT query to avoid certain words in the value of a column?

I have a table called videos with a column named title and there is a set of words (around 50 words as of now but the number of words may increase) which is the knowledge base for filtering the ...
1
vote
1answer
39 views

Is there any drawback of MIXED replication mode?

So, recent mysql server allows three types of replication mode: STATEMENT, ROW, MIXED. They all have pros/cons, and I pick the mode according to site characteristics. When I get a replication error I ...
0
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0answers
539 views

Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause

CREATE TABLE approvalreasonexemption ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `personId` INT(10) UNSIGNED NOT NULL, `reasonId` INT(10) UNSIGNED NOT NULL, `createdBy` INT(10) ...
0
votes
1answer
57 views

Mysql remove binary log

Hello everyone we got situation over here. So, our mysql server is running out disk, after some investigation we found out that our mysql binary file have eat too many space. In order to purge the ...
0
votes
1answer
162 views

too many connection error mysql: how to calculate max_connections

how to calculate this values to get the best results to resolve this error "too many connection error mysql" and make my API faster in mysql wait_timeout = ?? max_connections = ?? ...
0
votes
2answers
283 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 ...
0
votes
1answer
3k views

Executing try catch block in mysql stored procedure

In my mysql stored procedure I want try catch block but it gives error in my mysql stored procedure . I want my select query to be in try block and if it executes correctly I want other query to ...
1
vote
5answers
6k views

MySQL gives me:“Can't open and lock privilege tables: Table 'host' is read only”

I am facing problem restoring a MySQL database. My primary database was MySQL 5.1 and now I am trying to copy it to MySQL 5.5. The database was backed up by using Xtrabackup. I am using Ubuntu ...
1
vote
1answer
332 views

How to take physical backup of MYSQL database

I am trying to find out some tool which can take physical backup of MYSQL database. Like mysqlbackup but it is not open source. There is mysqldump but i want to take physical backup. Can someone ...
1
vote
1answer
48 views

How to cache query for re-use in following UNION of queries?

I need to perform query, save the result and re-use it multiple times in one session (something like WITH in Oracle DB). This is the query I want to save: SELECT `event`.id, event.name FROM ...
1
vote
1answer
86 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: ...
0
votes
1answer
501 views

Whether to use or not to use: DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

In one Database table, created_at & updated_at are defined as: `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP `updated_at` timestamp NOT NULL DEFAULT ...
3
votes
1answer
407 views

MySQL / Fusion IO Configuration Question

I need a little configuration optimization. I think what I have is pretty good but feel like there's still room for improvement. Current Config [mysqld] user=mysql datadir=/var/lib/mysql ...
7
votes
3answers
4k views

How costly is opening and closing of a DB connection?

How CPU intensive is opening and closing of a DB connection (for a web app) in MySQL ... when the DB software is on localhost? ... when the DB software is on another machine?
1
vote
1answer
61 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 ...
2
votes
1answer
128 views

Why does MySQL increment the auto_increment value when there's a constraint violation?

I have a table in a MySQL database with one column id, which has auto_increment and the Primary Key. There's also a Unique constraint in this table, on different columns. I noticed that when I try to ...
0
votes
1answer
12 views

MYSQL variable in function

Can anybody tell why the value of @URlID is always -1 even when i know the query will return a result? I have tried any possible type of variables and any possible way of inserting into the variable ...
1
vote
1answer
220 views

Mysqldump --flush-logs results in small backup files?

New to MySQL and just learning how to setup a daily full backup (binary logs enabled). My goal is to run a daily full backup of the databases/schemas and reset the binary log. I'm currently using an ...
1
vote
1answer
161 views

MySql - unique key not working

I have the following table: CREATE TABLE `timeline_lists` ( `id` int(11) NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `list_type` int(11) NOT NULL, `s_object_id` int(11) NOT NULL ...
1
vote
2answers
116 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 ...
2
votes
2answers
3k views

High MySQL “InnoDB Writes Per Second” - Can't see the queries?

On our live MySQL 5.5 database server, we use MySQL Workbench for running manual queries, checking running queries to see what's going on, etc. I noticed today that on the "Server Status" tab there's ...
0
votes
2answers
148 views

How to verify data dumps between two MS SQL and MySQL

I'm trying to verify data exported from MSSQL and imported into MySQL is 100% accurate using MD5 hash. On Linux, I'm using md5sum and WinMD5 on Windows. The encoding is the same: UTF8. I tried both ...
0
votes
1answer
46 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 ...
0
votes
0answers
64 views

Best upgrade path for MySql 4.1 to 5.5?

Background Our production environment runs on a system that nobody wanted to update for a long period of time. With a new sherrif in town, we're going to update it. Production is MySql 4.1 with ...
3
votes
2answers
62 views

Fetch all words from column with like

I have a column with description and inside it can contain # value . what I want is all the words searched from that column with #tag This is my query SELECT description FROM photo where ...
1
vote
2answers
571 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 ...
1
vote
0answers
54 views

pt-online-schema-change with circular replication

So I have an alter table (adding 4 columns) to do on a fairly large table (74 million rows). The problem is this table has firstly to remain online and writable during the whole operation and ...
0
votes
0answers
9 views

Why pages not made young is zero?

In results of Show INNODB Status showed me very weird result: Pages made young 81821279, not young 0 The official statement says: Pages made young, not young: The number of old pages that were ...
2
votes
2answers
324 views

How to generate auto increment values for my duplicate column in my sql?

How to display when i was run to find duplicate values from my table at this time i want to add new column in select statement with auto increment values SELECT * FROM tutorials_tbl WHERE Lscno IN ...
0
votes
2answers
2k views

How to resolve: Specified key was too long; max key length is 767 bytes [duplicate]

Our server is creating a lot of tables and one of them is the Lock_ table. We are using MySQL 5.5 on Percona. Also we are using utf8_general_ci and utf8. It throws the following error when creating ...
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votes
1answer
95 views

Is there any limit for MySQL database rows

I'm creating a database website which has a lot of data (Username,name,address,posts etc). Is there any limit to store database rows? (I have a table with more than 100,000 rows) How to host this ...
0
votes
1answer
64 views

What is wrong with this statement? 'Unknown column'? [duplicate]

I'm not used to the 'as' keyword and I thought it would be a nice idea to use it. So why do I get an 'unknown column' (eid) error? I use mysql... select t1.index as eid, t1.col1 as col1, t1.col2 as ...
1
vote
1answer
3k views

Add database to existing replication which uses binlog_do_db?

We have two MySQL 5.5 servers running on Ubuntu 12.04. We are successfully replicating 3 databases from server01 to server02, but need to add a 4th (new) database. Our my.cnf on the master has: ...
1
vote
1answer
774 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 ...
0
votes
0answers
91 views

Soundex on a Large Table

I had a table of names, containing 200,000 rows. This has now been updated to include over 11 million rows. The table is queried using a SOUNDS LIKE 'str' and the result is then passed through ...
0
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0answers
23 views

Unaccounted for MySQL Processes

I am running a MySQL 5.5.38 on a VM running Ubuntu server 12.04. At certain times of the day around 12 mid day, CPU Utilization and loads spikes to over 90% with the MySQLD Process accounting for most ...
3
votes
2answers
104 views

Is this substring_index behaviour documented or a bug?

mysql> show variables like 'version'; +---------------+-------------------------+ | Variable_name | Value | +---------------+-------------------------+ | version | ...