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
206 views

View last several innodb deadlocks

I see that I can view the latest deadlock in mysql/innodb, but is there a way to view past deadlocks? We have two deadlock issues, one being important and the other not. The less important deadlock ...
0
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0answers
51 views

MySQL JDBC Driver puts transaction in read only. Why?

Using the MySQL JDBC connector with a MySQL 5.6.22 data source defaults the transaction mode to read only. Anyone know why?
1
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1answer
67 views

Finding out the exact size of the database after inserting records?

I have this query: SELECT table_schema "db.name" , Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" FROM information_schema.tables GROUP BY table_schema; Does this ...
1
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0answers
38 views

Can MySQL Index Merge an Composite index with a single column index?

I am tuning a query and currently have an index as following : Index 1 : (col1, col2) An example query would be : SELECT * FROM t1 WHERE col1 = '1' AND col3 = '2'; I have created an index on ...
0
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0answers
75 views

Slow Query Performance - Can't Debug

I have a MySQL query that I am trying to debug the performance issue but cannot. I know that the majority of the query is reading/processing rows (Sending Data state). However, in the explain output, ...
0
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0answers
32 views

Oddness with MySQL with InnoDB - CPU capped at 50%

I have MySQL 5.5.22 with InnoDB, running on multiple c3.8xlarge EC2 instances. Which is to say, the VMs are set up with 32 CPUs & 59 GB RAM There are no CPU controls in MySQL, right? Then why ...
1
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1answer
35 views

Queries that ran, and the number of times they ran

I want to profile a running web application in dev on a mysql 5.5 database. The web application uses hibernate and I am able to see that a rather large number of queries are run against the database. ...
0
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0answers
36 views

unable to add data source on idashboard admin

I am in the process of adding data source on iDashboard , Data Source section. So, for that I downloaded the driver from here which is mysql-connector-java-5.0.8-bin-jar and currently trying to enter ...
1
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2answers
180 views

One to many join, Sum from both table

I have two tables: orders and ordersdetail...(partial table) orders- id(primary key), amount, date( index) orderdeails- id(primary key), skunitid, quantity, order_id Each order has multiple order ...
1
vote
1answer
117 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 ...
0
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1answer
93 views

SQL INSERT and UPDATE queries run far to slow

I have two queries that run far too slow and I have no idea why. Both tables contain about 500000 rows. Each call needs ~20 minutes and the they have a really high CPU usage (~90% on Mac). I have ...
1
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1answer
1k views

Why mysqldump is returning with error 1143: Couldn't execute 'show table status like

I ran the following command to create a mysqldump mysqldump -ubackup -psomething --single-transaction --quick somedatabase | gzip > 4_19.gz I got following error after 60% (estimating checking ...
1
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4answers
138 views

How to backup live mysql database?

I have 12 GB MySQL InnoDB Database with around 800 queries per second. No sooner I start 'mysqldump' over it to make backup I start getting '503' on my website. How do I make backup of my live ...
-2
votes
1answer
16k views

How to get MAX and MIN in GROUP BY query?

In a simple query SELECT col1, col2, col3 FROM table1 GROUP BY col1 each row includes the first value of col2 and col3 for each unique value of col. How to select MAX and MIN for each value of ...
0
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2answers
72 views

Mysql replication from existing slave to new slave

I'm hoping you experts can help advise me, I've got this topology: Live DB(Master) ----> Backup Server (Master and slave) ----> Test DB Backup server is a slave of Live DB, and Test DB is a slave of ...
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0answers
488 views

How to solve MySql Slave Error 1452 Foreign key constraint fails?

I am site administrator. We use to have a mysql 5.5.40 master(db01) - slave(db02) setup. One day our master server (db01) got down due to hardware failure. So we switched our site to slave (db02) ...
3
votes
2answers
160 views

Why wouldnt Mysql use index on the Primary query in a nested query

I have two tables: search_criteria and pricing. There is an index on search_id column in search_criteria table and on pricing_id column in pricing table. But running this nested query does not use ...
0
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0answers
23 views

Trying to create a trigger to fill two columns (MySQL)

I am trying to create a trigger to update columns on a table when a new record is added to another table. This is the code I am using CREATE TRIGGER `hire` AFTER INSERT ON `hire` FOR EACH ROW BEGIN ...
0
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1answer
162 views

Adding a primary key to an existing table in mysql is taking time

22 hours ago I started a script that executes an alter table to add a primary key to a table which has 225 millions of records. MSISDN is the only column. In showproceslist its process status is ...
1
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2answers
319 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: ...
2
votes
3answers
1k views

how to install mysql on mac?

My Mac runs Mac OS X, version 10.7.5., so it's a 64 bit system. First, I downloaded mysql-5.5.28-osx10.6-x86_64.dmg. Then I double clicked mysql-5.5.28-osx10.6-x86_64.dmg, it's mounted, and shows ...
2
votes
1answer
244 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
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3answers
527 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
115 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
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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
314 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 ...
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0answers
380 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
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0answers
860 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
84 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: ...
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0answers
53 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
228 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
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1answer
99 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
405 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
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1answer
347 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
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1answer
95 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 ...
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0answers
605 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
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1answer
61 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
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1answer
174 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
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2answers
304 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
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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 ...
2
votes
5answers
7k 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
379 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
50 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
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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
527 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
416 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
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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 ...
2
votes
1answer
142 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 ...