InnoDB : MySQL's ACID-compliant Storage Engine

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2answers
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Transaction basics. What is the result of 2 transactions running concurrently?

I have a rather basic question on transactions. Assume a table Account with a column amount. Now we have the following code: BEGIN $amount = SELECT amount FROM ACCOUNT WHERE id = 123; $amount = ...
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1answer
86 views

Why is setting open_files_limit making MySQL slow?

We noticed that adding open_files_limit in /etc/my.cnf is making server slow. Reference : What variable(s) to look to maintain MySQL speed of scanning through all database tables while it starts?
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1answer
359 views

ib_logfile0 and ib_logfile1 got deleted

After restoring from a percona-xtrabackup without a preparation step, ib_logfile0 and ib_logfile1 were not present in the restore data. Therefor during startup the following message is observed: ...
2
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1answer
591 views

Why does auto increment jumps by more than the number of rows inserted?

I am very perturbed by this weird behaviour I am seeing in the auto_increment value recorded in the bidID of a Bids table after performing bulk insertion using a stored procedure: INSERT INTO Bids ...
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3answers
291 views

What does “InnoDB stores its tables and indexes in a tablespace” mean? [duplicate]

Was reading the mysql engine innoDB tutorial, I came across this sentence "InnoDB stores its tables and indexes in a tablespace" Can any body explain me this what does it means. Thank you :)
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0answers
116 views

MariaDB Galera Cluster

I have two mariadb servers in cluster that is working galera and xtradb. it is my primary server configuration: [mysqld] datadir=/var/lib/mysql query_cache_size=0 binlog_format=ROW ...
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1answer
73 views

Is there a table size above which SELECT performance degrades significantly?

In MySQL, does SELECT performance degrade significantly after a certain table size? I have a table with about 107 million rows and some queries seem stuck in "Sending data" for a long time. Of course, ...
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2answers
129 views

What variable(s) to look to maintain MySQL speed of scanning through all database tables while it starts?

We have few thousand small databases with total .ibd files of about 800000. We noticed that MySQL takes couple of minutes to stop but about two hours to start. For e.g. while MySQL is starting and ...
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1answer
63 views

The most efficient method to obtain the total entries into a mysql table

I have a table that has a very high usage (insert/update/select) - one of the operations is to obtain a count of the number of rows. So far I've been using the classic select count(pk) from table but ...
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1answer
544 views

how to recover .ibd and .frm files in mysql

so i am developing java application with mysql 5.6.13, few days before i purchased new laptop, from previous laptop i forgot to create dump of application instead i copied folder of my database(.ibd ...
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1answer
31 views

Check whether MySQL Innodb Rows are compressed

After setting the various variables to enable compression on the Innodb Barracuda tables, what query will you use to check that those tables are indeed compressed?
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1answer
257 views

Error 1005: Can't create table can't find where the problem is

I have created a EER model using MySQL Workbench (latest release). Apparently all is fine but when I try to do a FORWARD ENGINEER I get the common Error 1005: Can't create table. As suggested in this ...
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1answer
22 views

Mysql InnoDB exsited but can't show it

I have a InnoDB table A , While I type "show tables" , I can't see it. Even I type "drop table A" , it responses "table doesn't exist" . While I create a table B which refers from A , table B can ...
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1answer
104 views

InnoDB to MyISAM Conversion Problem

I have a dedicated server based on CentOS 5 OS , mysql 5 and phpmyadmin I was trying to convert all database tables from InnoDB to MYISAM. I tried to do it by setting in /etc/my.cnf file the value ...
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1answer
1k views

Compressing Base64 Encoded Image in Database Field. Table Size too Large

Database Info Database Type - Percona MySQL. Table engine - InnoDB. I have a database table that is currently using 17GB at 400,000 rows. This size is mainly because I'm storing a 40kb base64 ...
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1answer
202 views

Error while importing sql - Specified key was too long; max key length is 1000 bytes

I am trying to import an sql file which shows me the following error: Error SQL query: -- -------------------------------------------------------- -- -- Table structure for table `users` -- CREATE ...
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1answer
310 views

MyISAM with Innodb in the same Wordpress database reduce performace?

My new Wordpress database all the Wordpress created tables use InnoDB engine and plugin created table use MyISAM. But older site database all the tables use MyISAM table engine. I use MySQL ...
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0answers
22 views

row locking with innodb [duplicate]

What is the most efficient way to lock a specific row for within a mysql transaction. I am currently using for update using select is there another method that im unaware of? if not are mysql locks ...
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1answer
41 views

mysql multiple database prioritize innodb buffer pool size

With a mysql instance and multiple databases within that instance is there a way to allocate which database you would like to assign priority to the buffer pool size?
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0answers
28 views

Temporary table created on disk, with 14mb of database

i have only one database (on one machine) with size 14 mb for temporary table i have this configration max_heap_table_size= 1000M tmp_table_size= 1000M sort_buffer_size=4M join_buffer_size=4M i ...
2
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1answer
134 views

row locking within ACID transaction innodb

I have a financial transaction that looks something like this (pseudo): begin select record for update update record(same record as selected) insert another record into another table ...
0
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2answers
214 views

MySQL High Availability for InnoDB

I am looking for MySQL High Availability with huge transactions. I prefer to go with InnoDB Engine. I prefer to use MySQL Master - Slave Replication. However, this option provides us Manual fail over ...
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1answer
169 views

MySQL, temporary on disk table on primary key retrieval?

MySQL 5.5.24, Windows 7 64-bit. I've InnoDB table with primary key defined on three columns: CREATE TABLE `common_descriptions` ( `object_id` mediumint(8) unsigned NOT NULL DEFAULT '0', ...
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0answers
47 views

Does union all have an enforced ordering

I know that a union does a de-duplication so can jumble the results, but I can't find a definitive answer for union all Example query select id from ( select id from table where id = 1 union all ...
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1answer
217 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
132 views

What is a storage need for MySQL index on Varchar(100) in InnoDB?

I have a InnoDB table, which has EMail column (VARCHAR(100)), now I will run script which will hash some of that email addresses. I am wondering, if there is a difference in data storage (for example ...
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1answer
786 views

InnoDB: very bad performance on INSERT/UPDATE

Lately I have really big problems with INSERTs and UPDATEs. On my website 80% of all queries are SELECTs but in query slow log there are only INSERTs and UPDATEs. My dedicated server has 32GB RAM, ...
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1answer
120 views

I have delete database from mysql but storage is not freed

I have deleted multiple databases (schema) from mysql on amazon RDS but the storage is not freed, is there anything else I should do to free up the storage? I have a mysql database that the total ...
5
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1answer
2k views

MySQL 5.1 to 5.6: massive performance hit

Okay, this is possibly three questions. I want to move my existing MySQL 5.1 database using MyISAM to 5.6 using InnoDB for what I think are a host of obvious -- and possibly even good -- reasons. ...
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1answer
316 views

Copying MySQL tables, InnoDB tables not recognized

I have to set up a database copy on my local computer. The problem is that that I have given just the raw database table files (.frm, .ibd, .MYD, .MYI). I created the database by creating a folder in ...
1
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1answer
57 views

How to calculate the space I need for the indexes?

CREATE TABLE info( home CHAR(10) CHARACTER SET latin1 NOT NULL, id TINYINT UNSIGNED NOT NULL, galaxy TINYINT UNSIGNED NOT NULL, galaxy_pos INT UNSIGNED NOT NULL, events TEXT NOT NULL, UNIQUE ...
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4answers
414 views

innodb DEPENDENT SUBQUERY very slow

Here is some innodb table. It insert,update,query very frequently. tn is product id col is product sub id tindex is product description.(store by each word) date is product add date stored by ...
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0answers
292 views

MySQL Innodb Concurrent Inserts and Selects - can't use multiple threads on FreeBSD

We have an application that needs to be dumping rows into some tables at a much faster rate than it currently is. It is a dual processor xeon DB server with 48gb of ram and a 4 TB disk RAID 10 (for a ...
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1answer
196 views

Upgrading mysql myisam 5.1 to mysql 5.6: force innodb on restore?

I inherited a DB using myisam on mysql 5.1 because of the need for fulltext search. I now read that fulltext search is available on mysql 5.6 innodb. Doing this would solve a lot of problems, as long ...
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0answers
63 views

InnoDB crashes frequently

My Innodb Engine is getting crashed frequently. I could not find the reason behind this. This is the error log: 140129 9:22:49 [Note] Plugin 'FEDERATED' is disabled. 140129 9:22:49 InnoDB: The ...
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1answer
111 views

What is the best partition technique for large table with TEXT column?

MySQL: What is the best partition technique for large InnoDB table (around 1.5M rows) with TEXT type of column? There is a FULLTEXT index on the TEXT column, which is very essential for my searching ...
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0answers
51 views

Count how many locks required for a MySQL (InnoDB) query

I'm performance tuning a very data-heavy mysql application. It has a purge system that often seems to cause lock timeout errors for users. Based on my research I have a few adjustments to the query to ...
0
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1answer
194 views

Native replication from Percona XtraDB Cluster to a standard stand-alone slave

I'm replicating from one node of a three-member Percona XtraDB cluster to a separate slave, using regular MySQL replication. The node is set to write binlog in ROW mode, with log_slave_updates=true ...
2
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1answer
213 views

Optimize table and query, aggregate by date or date-hour

I have a table storing sensor data (100M rows currently) from stations from different sites. In my case, sites may have many stations. Create table statement is as follows: CREATE TABLE sensor_data ( ...
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0answers
70 views

Mysql query getting hung!

I am using mysql 5.5. I create following temporary table: CREATE TEMPORARY TABLE IF NOT EXISTS tempdb.%s ( `count` int(10) NOT NULL, `m_class` enum('SMS','EMAIL') NOT NULL, ...
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0answers
542 views

The total number of locks exceeds the lock table size, even after increasing buffer pool size

I am trying to partition a table with 200 million records in it. This table already exists: CREATE TABLE linkmap_ntoken ( target_nToken varchar(200) NOT NULL, ntoken_hashcode int(15) NOT NULL, ...
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1answer
567 views

Recover an Innodb mysql database from an EBS on Ec2

My instance crashed on AWs, and i had to create a new one and mount my Vol that contain my web application and the Mysql Database. After i stoped the Mysql Server i mounted the vol and also mounted ...
2
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2answers
192 views

Should I replace my varchar primary key with an integer primary key?

I have a table that has a varchar primary key that's associated with "Base Product Codes". They rarely change, and if they do, it's usually just being deleted or added. I figured it would be better ...
2
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1answer
307 views

Strange things with Avg_row_length

The data from one tables is dumped to file and inserted into calls_old table with load data infile it shows Avg_row_length 7366. Later I dumped table with mysqldump, droped table, then created again ...
1
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1answer
151 views

Can anyone offer an opinion on handlersocket vs memcached performance in MySQL 5.6

I must say I was a little mis(un)-informed about the MySQL Memcached plugin which offers the same NoSQL like access to InnoDB tables as HandlerSocket, I had only had experience with entirely ...
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1answer
44 views

Why does TokuDB say to remove innodb_buffer_pool_%?

The TokuDB quick start guide says "After converting your tables to TokuDB, you should comment out the global options related to memory caches (ie: innodb_buffer_pool%)." If TokuDB supports both ...
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0answers
208 views

Migrating from Wamp to Xampp - table doesn't exists

I have a directory with files where MySQL database was stored when there was used Wamp. Now I would like to use this data to read it using Xampp. I tried to set datadir in 'my.ini' file to that ...
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0answers
102 views

.myd and .myi versus .frm and .ibd

I'm new to MySQL.I have trouble finding the .frm files and .ibd files in Windows 8 Explorer.They seem hidden and I have to find them using 'Find' and 'Open File Location', not sure how to make these ...
2
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1answer
5k views

Recover MySQL database from data folder without ibdata1 from ibd files

My WAMP directory accidentally get deleted by another user. Only data folder in MySQLis available. And, in that only database-folders (folders in "\bin\mysql\mysql5.6.12\data\" with name of databases) ...
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0answers
29 views

“Binlog has bad magic number” - recoverying InnoDB tables

A system crash raised the error in the title. I've tried the suggestion here, but then I can't access any of my InnoDB tables. They are still there, but data is missing. The provided solution ...