InnoDB : MySQL's ACID-compliant Storage Engine

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MySQL 5.5 Runs Out of Memory, Drops All Connections When Creating Many Databases

I'm running into a problem when I create a large number of databases consecutively on an Amazon RDS db.m1.large instance. The MySQL Engine Version is 5.5.23. At some point, the RDS instance drops all ...
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Can't create table, but table doesn't exist

I'm using these steps to create a table my_user, that already existed but somehow vanished from my database my_db: mysql> USE my_db; mysql> DROP TABLE my_user; mysql> ERROR 1051 (42S02): ...
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1k views

How to decide whether to enable MySQL query cache using InnoDB

How should the decision to enable / disable the MySQL query cache be made, on a server that uses just InnoDB tables. Say for example, if the cache is enabled, then how should the output of: SHOW ...
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1answer
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Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance?

We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and ...
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1answer
336 views

Fill ibdata1 With Zeros/Nulls/etc Or Change A Table's Tablespace

I have a MySQL 5.5 server running on CentOS 6. The MySQL package is a MySQL-released version (MySQL-server-5.5.28-1.el6.x86_64), not the stock CentOS one. I have moved an existing database over from a ...
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2answers
3k views

How to analyse innodb status on deadlock in insert Query?

I have a dead lock which i have posted here. I managed to get the innodb status from my server. Here is the Innodb status. OS WAIT ARRAY INFO: reservation count 247864, signal count 247470 Mutex ...
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2answers
2k views

Similar function NOWAIT in MySQL

Select for update nowait doesn't work in MySQL 5x (innodb). Is there any function like NOWAIT in MySQL?
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62 views

Too much IO to MySQL InnoDB log files

I am using MySQL version: 5.5.38 I have dedicated HDD to InnoDB log files using innodb-log-group-home-dir option. atopsar -d 30 shows big load (>50%) to this HDD The thing is that I have only 75 ...
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282 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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2answers
2k views

How to optimize MySQL for large BLOB updates

I have a table that holds large BLOBs (up to 10M), and is updated frequently. The problem is that UPDATE statements can take up to 1 second to execute, and due to app design this blocks UI. I need to ...
0
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1answer
273 views

Information about Disk Storage MySQL

I am trying to create an application for monitoring MySQL,in my application there's a part of monitor DISK STORAGE, so after more research I have not found how to calculate : used and free size of ...
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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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1answer
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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 ...
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2answers
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Full text search results in a large amount of time spent in 'FULLTEXT initialization'

I'm currently trying to run some queries against a data dump of Stack Overflow's comments. Here's what the schema looks like: CREATE TABLE `socomments` ( `Id` int(11) NOT NULL, `PostId` int(11) ...
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4answers
988 views

Is tuning the innodb_buffer_pool_size important on Solaris ZFS?

We're running a moderate size (350GB) database with some fairly large tables (a few hundred million rows, 50GB) on a reasonably large server (2 x quad-core Xeons, 24GB RAM, 2.5" 10k disks in RAID10), ...
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4answers
140 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 ...
3
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1answer
779 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 ...
3
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1answer
516 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 ...
3
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1answer
3k views

Why does that query cause lock wait timeouts?

From time to time, I find a lot of these errors in my PHP error log: MYSQL.1213: Deadlock found when trying to get lock; try restarting transactionSQL The problem persists for about 2 or 3 minutes. ...
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2answers
5k views

Finding and fixing InnoDB index corruption

I encountered a new issue yesterday with one of my MySQL 5.5 slave DBs that runs on EC2 in AWS. The DB was created from a snapshot of another slave. The data is correct, but for at least one table a ...
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3answers
2k views

InnoDB insertion faster

I'm a graduate school student researching OLAP with Mondrian OLAP. So I want to insert data into InnoDB (MySQL 5.5) faster at the initial loading. In this environment, the only user is me, so I think ...
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2answers
777 views

MySQL insists on trying to use InnoDB even when told not to, please help

We're trying out MySQL 5.5, and have installed it on one of our slave servers as a test run. Our main server is 5.0, and we have zero optimization here for InnoDB, so I want everything to just be ...
3
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1answer
514 views

why is mysql still writing data two hours after all transactions have stopped

I have a mysql server used mostly as data warehouse. It loads about 4-5GB of data per day (actual database size, not the size of the source data). Lately, I noticed something peculiar. After I ...
3
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1answer
1k views

Are many NULL columns harmful in mysql InnoDB?

As I explored the clustered B-tree index system of InnoDB, I think that the presence of many NULL (or small) columns has no significant effect on InnoDB performance. Does the presence of excess ...
2
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1answer
67 views

Wordpress blog where pages are almost-always served from cache: SSD or more RAM?

I am working on the design of a Wordpress blog which when finished will almost-always serve pages from disk cache and this is because all posts will be published in batch and then cached, with at ...
2
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1answer
138 views

InnoDB: “Only one log file found” after binary import

My first one on DBA... After successful upgrading a master MySQL server 5.5 to 5.6.17 (CentOS 6 VPS serer), I done and moved my binary backups to a slave server (same version 5.6.17 but different ...
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1answer
158 views

Optimize Percona MySQL InnoDB 3.2TB database

(Before you will call me an idiot or start laughing, please remember it's a real deal on my side and I cannot cancel this assignment as it is a part of a bigger project) I have a database server that ...
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2answers
332 views

How to monitor InnoDB Disk I/O Required for MySQL?

I am doing an estimate on how much i/o[disk read write] on Mysql 5.6 [innodb storage engine], for getting idea how to calculate total number of disk read write i have searched a lot on SO on DA and ...
2
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1answer
878 views

MySQL Index creation failing on table is full

UPDATE: tl;dr: The problem was MySQL uses the TMPDIR when creating indexes. And my TMPDIR was the one running out of disk space. Original Q: I'm trying to add an index to an InnoDB table, and ...
2
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1answer
121 views

Migrate from innodb_file_per_table to off in MySQL

We have a large number (2,500+) of databases and users in MySQL 5.6 on a single virtualized server (4 cpus and 8GB of memory). All the tables are using InnoDB. The actual data size is not very large ...
2
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1answer
360 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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3answers
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Purge old records from mysql ibdata1 file

Is it possible to purge old records from an ibdata1 file without taking down the database attached to it? Records that have been deleted from the database are still present when I scan ibdata1 for ...
2
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1answer
79 views

Is there any way to use different InnoDB settings for different databases on the same server?

From what i know, this is not possible but i'm surprised its not highly requested feature. I'd love to be able to have one db using InnoDB in ACID compliant mode and another db on the same server used ...
2
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1answer
244 views

Why would one use the Innodb Plugin instead of the builtin Innodb in Mysql 5.1? (GPL)

Innodb works in Mysql 5.1 whether or not the innodb plugin, ha_innodb_plugin.so is loaded at startup or not. Configuration dependent of course. What are the advantages and disadvantages of either ...
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0answers
871 views

Query getting periodically stuck in 'copying to tmp table' state, never completes

I am running Wordpress on a dedicated server with a MySQL backend. I have a query that usually takes <1 second to execute, but periodically, this query will get stuck in a 'copying to tmp table' ...
2
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1answer
431 views

Does the size of the primary key contribute to table size?

I have a table (InnoDB) with data length around 36G and index length 23G. It had a composite primary key across three columns. As an initial attempt to reduce the size of this table, I dropped the ...
2
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1answer
5k views

MySQL: Error reading communication packets

I get this warning in mysql, [Warning] Aborted connection 21 to db: 'MyDB' user: 'MyUser' host: 'localhost' (Got an error reading communication packets) I have been through few topics in google ...
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1answer
60 views

Do I need to reenter old data after adding an index to a table?

I want to add index to my tables. Some of my tables already have couple thousand rows. Do I need to reenter my stored data after adding index to columns (to make them aware of index/so the indexing ...
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2answers
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mysql 5.5 corrupt - missing temporary table

One of our mysql instances crashed and failed to start: 120422 10:04:13 InnoDB: Error: trying to open a table, but could not InnoDB: open the tablespace file './databasename/#sql-29f6_45.ibd'! ...
2
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1answer
655 views

Number of locks exceeded when adding foreign key constraint

I'm adding a foreign key constraint to table a (17mil rows) that references table b (15mil rows): >ALTER TABLE a ADD FOREIGN KEY (b_id) REFERENCES b (id); ERROR 1206: The total number of locks ...
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172 views

Very high load avg for MySQL database [closed]

I have a backend server which response to my clients app, it has more than 20k~25k hit per second and this make my server load average very high, I believe that my MySQL config is not appropriate. In ...
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1answer
66 views

Table is dropped but ibd file still exists

I was dropping some unwanted tables I have in the MySQL. When I run a drop table, its showing table doesnot exists. But when a check in the data directory, the .ibd file exists and its almost 1GB. How ...
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1answer
39 views

Change column without interrupting service

We need to change the data type of a column in a large table (~1.7 GiB) from VARCHAR(1024) to VARCHAR(512) in order to be able to create a secondary index over two columns. We're using MySQL 5.6 with ...
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1answer
741 views

Deleting & Reclaiming space from InnoDB table

I have a 700GB InnoDB table which I'm not writing any more data to (only reading). I would like to delete the older data it holds and reclaim that disk space (as I'm running out of it). The delete ...
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1answer
108 views

creating table result in errno 150

I'm trying to create the following schema, but I'm getting errors when I'm trying to create project and staffphone tables. Not sure what is it complaining about. mysql> CREATE TABLE staff( ...
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1answer
418 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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763 views

Converting live MyISAM table to InnoDB

I have a table that tracks web traffic. The table is constantly written and read from. Since table is pretty big in size I have to make sure the application will not "freeze" in the process of ...
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1answer
320 views

TokuDB database size unknown in phpmyadmin

In mysql server, I installed the TokuDB storage engine. I converted database engine InnoDB to TokuDB, but my table sizes show unknown in phpmyadmin.
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Is it possible to force drop of mysql tables with FK?

For dropping a table in which a Foreign Key is used in other tables, it is necessary to drop all other tables having FK connection with the corresponding table. Is there a short way to drop a table, ...
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1answer
294 views

Issues converting MyISAM table to InnoDB (auto column issue)

I'm having issues trying to convert a table from MyISAM to InnoDB in MySQL 5.6. The following is the table dump: -- -- Table structure for table `companies` -- DROP TABLE IF EXISTS `companies`; ...