InnoDB : MySQL's ACID-compliant Storage Engine

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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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4answers
248 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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1answer
1k views

How I prevent deadlock occurrence in my application?

I am developing an LMS application in PHP framework(Codeigniter 2.1.0). I am using MySQL database. All the tables in the database have innodb engine. I also created indexes on each tables. Now I am ...
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2answers
76 views

How to interpret the information spit out by innochecksum?

MySQL is using up a lot of the disk space. Running du -sh on the data directory shows a humongous ibdata1 file (around 1.7 terabytes). I found a very helpful article online and ran a modified version ...
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1answer
92 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
421 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
82 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
950 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
210 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 ...
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0answers
175 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
113 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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1answer
153 views

How big can innodb_doublewrite_file grow?

When I use the enable innodb_doublewrite_file ... How big can this file grow ? How can I calculate the optimal disk size, if it would be used only for this file?
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54 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 ...
0
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1answer
81 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 ...
2
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0answers
43 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
104 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 ...
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2answers
276 views

Help my database isn't performing fast enough! 100M Merge with 6M need < 1 hour!

I have a server right now receiving more raw data files in 1 hour then I can upsert (insert -> merge) in an hour. I have a table with 100M (rounded up) rows. Table is currently MyISAM. The table has ...
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1answer
145 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
57 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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1answer
235 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 ...
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2answers
105 views

Do I need a locking read?

I am inserting rows in a table, based on a value and on the existence of a row, which I get from SELECT statements. This function can be run concurrently, so I need to do some extra obviously. The ...
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2answers
110 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 ...
3
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1answer
35 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
158 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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1answer
175 views

Why are InnoDB's index keys limited to 767 bytes?

MySQL's official documentation states about InnoDB: An index key for a single-column index can be up to 767 bytes. The same length limit applies to any index key prefix. The meaning of this ...
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70 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 ...
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1answer
3k 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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2answers
971 views

Unable to change engine to MyISAM in MySQL

I have installed MySQL 5.6.10 on Mac OS X 10.6.5. My issue is that MySQL is using InnoDB as its default engine. I have checked following engines are supported in MySQL: show engines\G ...
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0answers
23 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 ...
0
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1answer
34 views

In MySQL, when using InnoDB, what happens to the way data is laid out on disk when the primary key is dropped?

In MySQL, when using InnoDB, what happens to the way data is laid out on disk when the primary key is dropped? Also, what happens when a new primary key is added?
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1answer
313 views

Speeding up a NOT IN subquery

Good evening, I'm currently up to try to improve the performance of some of my queries. As far as I know, statements like "IN" or "NOT IN" are even faster with a large amount of values if a subquery ...
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2answers
72 views

Mysql Windows Issues

I've been having allot of issues with my mysql databases on Windows dying on me. About once a week or so it will refuse to work and I'll spend all night poking at it & a few computer restarts ...
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1answer
909 views

Slow InnoDB INSERT/UPDATE/DELETE

Background A couple of weeks ago all of my INSERT's/UPDATE's/DELETE's became overall slow (not SELECT's). Before that, everything was normal (mysql statements executed in <0,01 seconds). Now a ...
3
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1answer
288 views

Mysql database slow responding to connects when having only few concurrent connections

We have a database setup with in master/slave. It runs innodb and its on a 8 core with 32gb. When i run "ab" to do a load test on a website (4 frontend webservers) which does the query's with 10 ...
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1answer
175 views

Data lost in MySQL InnoDB after crash

I found a 6-days rollback in a MySQL 5.6 community edition server installation. It seems that some logs were lost, and I cannot understand why. 2013-12-22 20:38:54 380 [Note] Plugin 'FEDERATED' is ...
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1answer
988 views

How to optimize InnoDB tables in MySQL

I’ve been researching how to optimize only fragmented tables in MySQL and reviewed this post on optimizing tables. It basically performs a query against the information_schema database for any table ...
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1answer
86 views

Is ANALYZE useful immediately after creating an InnoDB index?

Let's create a new index on an existing table: CREATE INDEX `IDX_some_index` ON `some_table` (`a_column`, `another_column`); Is this useful? ANALYZE TABLE `some_table`; Can anyone point to ...
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1answer
125 views

AWS RDS showing large growth in Write Ops/sec, despite low # DB connections?

I have a Multi-AZ AWS RDS instance running MYSQL 5.5 I've noticed that my write ops/sec are growing fairly rapidly, despite low (and sometimes zero) DB connections - see charts for Avg write ops/sec ...
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0answers
49 views

Overcoming the HDD IOPS limits on a billion row table? Is getting SSD the only solution?

I have a table with this structure: CREATE TABLE `requests` ( `userid` int(11) NOT NULL, `messageid` int(11) NOT NULL, `queueid` int(11) NOT NULL AUTO_INCREMENT, `problem_id` int(3) NOT NULL, ...
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3answers
14k 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?
2
votes
3answers
552 views

Making sense of INNODB buffer pool stats

After having read this page in the mysql documentation, I tried to make sense of our current InnoDB usage. Currently, we allocate 6GB of RAM for the buffer pool. Our database size is about the same. ...
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1answer
431 views

Delete data from huge InnoDB table from MySQL Master and Slaves

We have some huge tables in MySQL database, We have already archived/deleted data older than 2012 in 2013, Now we need to archive/delete data older than 2013 means we need to archive data for year ...
1
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1answer
178 views

How to use LOW_PRIORITY for heavy queries?

I have scheduled heavy UPDATE queries at administrator level, and since they are heavy UPDATEs with multiple JOINs, consume a huge amount of resources. I do not want them to stop end users from ...
0
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2answers
97 views

I can't get an import to go past 1.1gig

I can't get an import to go past 1.1gig. I have a large 4gig InnoDB table/database I would like to get on my "tried and true" box. Current config on this box I want to work with = Dell PowerEdge ...
0
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1answer
198 views

Why “.my.cnf” file is empty?

I want to edit some of InnoDB variables ,I go to the .my.cnf which is located in home/.my.cnf I found the file just empty. And when I check SHOW VARIABLES in MySQL it gives me all the variables and ...
0
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1answer
132 views

Where does mysql write temporary tables?

MySQL 5.1.x | Windows Server 2008 Data Directory is on a different partition. I have an innodb database (innodb_file_per_table is set) that I'm trying to optimize and I don't appear to have enough ...
0
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0answers
85 views

What are the steps to change tables engines from MyISAM to InnoDB?

I have a Datebase with 10MB size . The Tables' engines were MyISAM (table-lock level). So I deiced to change them to InnoDB (row-lock level). I used the sql query for each table : ALTER TABLE t ...
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2answers
194 views

MySQL - INSERT … SELECT .. FROM .. - Single transaction or transaction per row?

Question: I am currently working on a data migration. I need to migrate 2.5 million rows from one InnoDB table to another InnoDB table (with a different setup). I am using the following syntax to do ...
0
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1answer
40 views

is it possible to set engine for database (not the tables)?

There are about 250 tables in my database and they all have InnoDB engine. I imported them into a server. They were imported and were displayed in the tree structure of phpmyadmin (under the ...
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1answer
98 views

Need to optimize simple SELECT query for InnoDB table with 2million rows

I'd like to make this query the fastest possible, since it's called really often. SELECT login_events.id FROM login_events WHERE ( DATE(created_at) >= DATE(CURRENT_DATE) AND person_id = 1 ) ...