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

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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: ...
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39 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?
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149 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 ...
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1answer
93 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 ...
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2answers
253 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% ...
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1answer
73 views

Myloader command: Table doesn't exist

I took the backup of mysql database using mydumper command: mydumper -B mydb -o /backup/oct3 -s 500000 -c -m -S /tmp/mysql.sock -u root -p password@123 -v 3 Now, I am restoring mysql database ...
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1answer
219 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 ...
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1answer
93 views

mysql autoincrement counter

I need a way to keep auto-increment counter between mysql service restart. As docs states by default after restart mysql autoincrement counter start from max(id)+1. How can I keep the last ...
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1answer
55 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 ...
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1answer
36 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 ...
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376 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) ...
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1answer
45 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 ...
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1answer
138 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 = ?? ...
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2answers
241 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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2answers
84 views

about giving same column name in every table of database

I have a database with 5 tables. In every table there is a column for checking status. If i give the name to that column which is same in all the 5 tables; What will happen? Is it correct according ...
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1answer
2k 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 ...
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5answers
5k 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 ...
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1answer
231 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 ...
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1answer
42 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 ...
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1answer
85 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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1answer
440 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 ...
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1answer
366 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 ...
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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?
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1answer
55 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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1answer
105 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 ...
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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 ...
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1answer
189 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 ...
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1answer
108 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 ...
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2answers
102 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
2k 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 ...
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2answers
134 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 ...
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1answer
43 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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51 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 ...
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2answers
57 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 ...
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2answers
415 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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0answers
45 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 ...
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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 ...
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2answers
253 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 ...
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2answers
1k 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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1answer
80 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 ...
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1answer
60 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 ...
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1answer
2k 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: ...
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1answer
542 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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68 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 ...
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22 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 ...
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2answers
80 views

Is this substring_index behaviour documented or a bug?

mysql> show variables like 'version'; +---------------+-------------------------+ | Variable_name | Value | +---------------+-------------------------+ | version | ...
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1answer
44 views

Importing Data with Single .ibd file

I have one ".ibd" file with me. I have configured my local Database server with FILE_PER_TABLE option. i have two question here. When i was trying to restore/import the IBD file, the engine expect ...
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2answers
995 views

query execution time in mysql

I have run the query in mysql which consists of approximately 33million records when i have executed the query select population1 < 200000 from city; it shows like this after execution ...
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3answers
379 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
223 views

MySQL my.cnf: innodb_log_file_size is missing

How to set innodb_log_file_size to MySQL database if there is no innodb_log_file_size in my.cnf configuration file? I'd like to backup via Percona Xtrabackup and the backup crashes at this point ...