InnoDB : MySQL's ACID-compliant Storage Engine

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character set, not set correctly

I have two database with a table with utf8 table, I wanted to change the encoding of a column, I used two scenarios but a problem happened to me. at first the table was like this : CREATE TABLE ...
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1answer
77 views

Can I emulate Oracle's autonomous transaction in MySQL?

I have a number of tables that have triggers on them that insert records in queueing and logging tables. The problem is that those inserts are then part of the same transaction. That means that any ...
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1answer
51 views

Mysql only using 10% of cache [duplicate]

I have a dedicated Mysql server that only uses 1.1 GB out of 16 GB ram (picture link 1). I belive this leads to my Disk I/O utilization beeing at 75% peaks (picture link1). How can i configure sql ...
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1answer
32 views

Altering a large table to INNODB

I have a table of 4GB(18 Million Rows) in MYISAM Engine on one of my slave server, and I want to convert it to INNODB Engine, the server is replicating from a master. I tried to use the ...
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1answer
48 views

Are InnoDB files binary compatible between Windows and Linux?

I have seen many posts about recovering InnoDB files. The versions I have are: Windows: 5.6.17 Linux 5.0.96 (I cannot upgrade this at this time) If I create a new InnoDB file on the Windows ...
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1answer
50 views

Which error codes are safe for `slave_skip_errors` with MySQL Innodb

Does anyone know which error codes are safe to ignore during replication, meaning the slave will remain consistent with the master? For example [mysqld] ...
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1answer
61 views

If I query records matching some value, why does InnoDB examine most of the records that had that value once, but have changed since then?

We have an issue with MySQL InnoDB performance. We insert records into a table with a status field value of zero, these records need to be processed by another task. When this another task starts ...
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3answers
22k views

Difference between On Delete Cascade & On Update Cascade in mysql

I have two tables in MySQL database- parent, child. I'm trying to add foreign key references to my child table based on the parent table. Is there any significant difference between ON UPDATE CASCADE ...
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1answer
51 views

memory leaks in innodb

I have MySQL server 5.6 and I use stress test to evaluate the performance of it. after the test the result of mysqltuner.pl was like below : root@master-1:/home/debian# perl mysqltuner.pl Please ...
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1answer
73 views

Why Write IOPS,Write throughput,Queue depth decreased on AWS/RDS after changing innodb_flush_log_at_trx_commit and sync_binlog?

I changed values for my Mysql parameters 1. innodb_flush_log_at_trx_commit=2(before it was 1) 2. sync_binlog=0(before it was 1) This has changed some of my parameters on AW RDS drastically ,here ...
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1answer
56 views

InnoDB AUTO_INCREMENT resetting itself without MySQL restart

We've recently noticed the following scenario happening in many of our databases: A record is inserted, and receives an AUTO_INCREMENT primary key. The record is deleted. Another record is inserted, ...
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23 views

How to improve my big MySQL database with low concurrence?

I have a MySQL database who is been used to storage a large amount of data, it doesn't have a lot of concurrence( its minimum), but every day a big amounts of data is loaded and also a profiling ...
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2answers
283 views

MySQL query INSERT INTO … failed - The Table “x” is full

I apologize if my question is incomplete or noobish, I have extremely limited knowledge of SQL but the boss wants me to figure this one out. Environment: Webmin/Virtualmin | MySQL version 5.1.73 on ...
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3answers
4k views

When is it safe to disable InnoDB doublewrite buffering?

MySQL InnoDB allows us to disable doublewrite buffering by setting innodb_doublewrite = 0. Other databases doesn't seem to allow this setting to be tweaked. How could InnoDB still be able to maintain ...
0
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1answer
40 views

Is it good idea to use RAID 1 mirroring to back up database content

I'm working on web hosting project. The planned system structure is going to be like this: one main hard-drive will contain the binary of mysql. A second hard-drive will contain the datadir the ...
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2answers
5k views

Deleting MySQL table with pending transactions

Is there a way to delete an InnoDB table or database with pending transactions in MySQL (preferably on file system level)? What happened: I use MySQL 5.5.28 and ran LOAD DATA INFILE… to import a ...
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3answers
6k views

Select query takes more time than it should

I have a MySQL database table with nearly 23 million records. This table has no primary key, because nothing is unique. It has 2 columns, both are indexed. Below is its structure: Below is some of ...
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0answers
26 views

Problem creating database and tables from script [duplicate]

I've done a model diagram with Mysql Workbench, when export the SQL script I run it on my MySql on my develpment ubuntu and works fine but when I run it on the production server the scripts fails. The ...
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2answers
63 views

Performance for MySQL InnoDB B+Tree index with many duplicate values

I'm trying to diagnose seemingly random performance issues with our database server. Below is a simplified scenario, hopefully generic enough to serve as a useful future reference for anyone looking ...
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1answer
45 views

How can I 'further' improve my table and queries

This question is an extension of this question. Where Rick James kindly provided a list of things I should change in my table and query. I also changed my application so that unused filters weren't ...
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2answers
24k views

How to solve “The table … is full” with “innodb_file_per_table”?

I have a MySQL database that holds a large amount of data (100-200GB - a bunch of scientific measurements). The vast majority of the data is stored in one table Sample. Now I'm creating a slave ...
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0answers
35 views

Need help with corrupted MySQL database

I could use some step by step help on using innodb to hopefully recover a corrupted MySQL database. We are running moodle on a ubuntu server which uses the LAMP stack. The database has been corrupted ...
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0answers
61 views

TokuDB vs InnoDB Database data size

I have two percona servers, one running with TokuDB tables and the other with InnoDB tables. On each server, i have create a single database, with a single table in it containing 10 millions records ...
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30 views

Table clustered-index and partitioning in innoDB

I have a table with 45 columns, 3 of which are relevant: table Transactions(tr_id : int primary key, client : int, tr_date : datetime); The inserts to the table are done client-by-client The ...
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1answer
179 views

MySQL 5.6 Server start fails: InnoDB Operating system error number 23

I use a local MySQL 5.6 Server (InnoDB) on a Windows 7 machine to store several schemas of a research project. Until yesterday the system ran without problems. During a query, MySQL Workbench ...
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2answers
549 views

Abnormally high MySQL writes and larger than normal Binary Log files. How can I determine what caused this?

We have a MySQL master database which replicates to a MySQL slave. We were experiencing issues where MySQL was showing a high number of writes (but not an increased number of queries being ran) for a ...
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1answer
35 views

Galera cluster: change the size of InnoDB Redo log files online?

We have a 3 node Galera cluster. I need to change the mysqld innodb_log_file_size parameter (see Changing the Number or Size of InnoDB Redo Log Files). I do this by stopping all 3 nodes and ...
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1answer
53 views

How does InnoDB represent composite integer keys?

Let's say I have the following table: Create Table Orders(server : tiny int, ticket : integer, primary key (server, ticket)); How is the composite primary key representation when stored on disk? ...
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2answers
40 views

Get table sizes without SELECT permission

I want a scheduler to run a simple SQL script to collect the sizes of tables in our MySQL database: SELECT table_name, data_length, index_length FROM information_schema.TABLES The user the ...
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1answer
55 views

MySQL 5.7 not accepting values of innodb_buffer_pool_instances greater than 1

I've been tweaking the values of the buffer pool size (innodb_buffer_pool_size) and the number of buffer pool instances (innodb_buffer_pool_instances) in the my.ini initialization file to optimize ...
2
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1answer
90 views

Moving the binary location of MySQL for replication

Is it possible to move the contents of /var/lib/mysql when setting up replication instead of doing mysqldump > for export and mysql < for insert on the slave? I want this because in our current ...
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1answer
50 views

Does innodb_buffer_pool_size accept “*GB” values?

I thinks innodb_buffer_pool_size is specified in bytes, would typing in values with unit (i.e 1024MB or 1GB) work? Has anyone already tried this? Specs: MySQL 5.6
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Disable/Remove Table Index for INSERT Performance

I am doing a database maintenance where I have to add new fields to a table with over 10GB of data about (20 million rows). To solve that I renamed tableA to be old_tableA and created a new table ...
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1answer
53 views

Could I set my InnoDB MySQL Server session state for SQL_SAFE_UPDATES and INNODB_FLUSH_LOG_AT_TRX_COMMIT?

Could I set my InnoDB MySQL Server session state for SQL_SAFE_UPDATES and INNODB_FLUSH_LOG_AT_TRX_COMMIT using MySQL Workbench's SQL Query window or MySQL Connection Navigator instead of in a c# ...
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1answer
8k views

MySQL INNODB corruption after server crash during concurrent truncate command

My server crashed today I think due to a concurrent truncate table command on one of our INNODB tables. The server could be restarted, but after it starts up, everytime I try to issue an SQL command, ...
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1answer
47 views

Does varchar(n) affect the number of records which can be stored per page even if you store less than n?

I'm struggling to find enough documentation to help me answer my own question. The common story seems to be that it doesn't make a difference to actual database size when you use a much higher value ...
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0answers
92 views

MySQL 5.6 Performance Tuning Issue

I have read and try lots of things about MySQL optimization and tuning. I tried most of them one by one according to our needs but nearly I got nothing. I am doing my test using some simulation ...
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5answers
348 views

How do I prove that the act of removing foreign keys doesn't corrupt existing data?

TL;DR: Prove that in practice, the execution of the alter table table_name drop foreign key constraint_name statement does not corrupt existing data. The important consideration is the execution of ...
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1answer
31 views

Does Mysql locks table while insert operation

I am using Mysql(INNODB) and does Mysql locks table when I do some insert operation? I have a huge table and it has lots of indexes. I do some research and Mysql doc says INNODB only locks rows not ...
5
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2answers
543 views

Foreign Keys doesn't work as I expect

Here are my tables; CREATE TABLE `borclular` ( `id` int(11) NOT NULL AUTO_INCREMENT, `tc` char(11) COLLATE utf8_turkish_ci NOT NULL, `borclu` varchar(255) COLLATE utf8_turkish_ci NOT NULL, ...
3
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3answers
4k views

ibdata1 grows exponentially when innodb_file_per_table is configured

I Have installed a MySQL Cluster with InnoDB (innodb_file_per_table enabled subsequently), but since I switched to innodb_file_per_table, the file ibdata1 grows (2GB at month). Is My my.cnf file is ...
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0answers
58 views

How can I restore a MySQL dump faster on Windows?

I am restoring some InnoDB and MyISAM .sql files that are on the order of GBs (ranging from 1 GB to ~ 10GBs) and they are taking a day or longer to restore. The command I am using currently is: use ...
3
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1answer
7k views

Why does MySQL (InnoDB) table get faster after OPTIMIZE TABLE, but then don't work?

I have a Django web application that stores data in a MySQL InnoDB database. There is a particular page that is accessed a lot on the django admin, and the query is taking a long time (~20 seconds). ...
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1answer
4k views

How to UPDATE a column to SET previous row value to NULL cells?

I have a table as id value 1 music 2 3 movie 4 5 6 book 7 8 Some values are missing, and I want to assign the value of previous row to produce id value 1 music 2 music 3 movie 4 ...
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How to restore InnoDB from files

here is the situation I fu*d up my mysql setup, before I did that I copied entire /var/lib/mysql directory to another location. Now fresh installation of mysql is back and I cannot restore my files. ...
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4answers
38k views

Is it safe to use innodb_flush_log_at_trx_commit = 2

I turned innodb_flush_log_at_trx_commit = 2 and get a very fast write speed. But is it safe be used in production web site?
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0answers
206 views

Avoid MySQL self-crashing on long semaphore waits [closed]

I run heavy queries on my InnoDB databases every night, and sometimes it causes long semaphore waits. More background in this question. What I have observed is that if the data is stored on an SSD, ...
4
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1answer
4k views

MySQL Bug required remedy : [Warning] Invalid (old?) table or database name '#sql-'

We have a master & multiple slave replication in our production environment. At first, I found this error in the mysql error log on the master and later on the slave. As for all the replication, ...
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4answers
88k views

MySQL: how to restore table stored in a .frm and a .ibd file?

I have previously saved a copy of /var/lib/mysql/ddms directory ("ddms" is the schema name). Now I installed a new MySQL on a freshly installed Ubuntu 10.04.3 LTS by running apt-get install ...
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0answers
42 views

Is there an equivalent of virtual columns in mysql?

Currently I'm taking a look at amazon's new aurora database and I'd like to check how my current setup performs there. The original table is on maria DB and contains a virtual column ...