InnoDB : MySQL's ACID-compliant Storage Engine

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Why pages not made young is zero?

In results of Show INNODB Status showed me very weird result: Pages made young 81821279, not young 0 The official statement says: Pages made young, not young: The number of old pages that were ...
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208 views

mysql - Recovering databases from ibdata1 , .frm and .idb

I have a server running a mysql instance which crashed today. Now there are a massive amounts of tables in multiple database exceeding over 200GB stored on disk. After the server crash mysql is ...
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54 views

Fastest engine for Mass Updates (only updates done on table)

I have a table of 2 columns and 60 million rows. I want to update the table by incrementing one field by 1 on various different rows (This is the only type of operation that will ever be done on the ...
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215 views

MySqlDump's DISABLE KEYS have no effect on import

I have a follow up to my previous question regarding import speed with Inno-Tables (suprise!). Scenario I try to import some big* database dump on my local dev machine in reasonable time. We have a ...
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Conversion to Barracuda/Compressed Rows Doesn't Free Disk Space

I'm currently converting large tables to the Barracuda file format. We are using file_per_table. I had one table that decreased from 4.3gb in size down to 1.8gb and we're very happy about this. ...
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61 views

Running a query on an improperly indexed, 600gb table

This is my first post on here and I'm really baffled by this. I have joined a team and somewhere in the past a horrific table was created which has been bloated to a point of 600+gb of data. ...
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53 views

mysqldump with --single-transaction seems to be “fixing” InnoDB tables with page corruption - why?

I'm trying to find out what exactly is happening here. I've been intentionally corrupting index pages in InnoDB tables, changing bytes in user record areas that actually contain information (largest ...
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Why is MySQL database is having irregular performance issues?

I first thought it was because of some bad queries, but it wasnt. It took 90 secs to execute a select statement on a table with two rows one column while during other times it executed within ms. ...
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3k views

Configuring MySQL (my.cnf) for MyISAM and InnoDB

I want to convert some (not all) the MyISAM tables to InnoDB. Here is my current my.cnf: pastebin.com/FW8YXtLQ What would be the best configuration? (need to add InnoDB settings, byecause there are ...
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71 views

MySQL FullText search on string shorter than 3 chars returns no rows

I have a MySQL table with some addresses in it. Let's say I have the following 2 rows: "10 Fake Street" "101 Fake Street" I'm trying to use fulltext search with MATCH() AGAINST(). I have set ...
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34 views

Importing Data with Single .ibd file

I have one ".ibd" file with me. I have configured my local Database server with FILE_PER_TABLE option. i have two question here. When i was trying to restore/import the IBD file, the engine expect ...
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MySQL instance stalling “doing SYNC index”

Problem An instance of MySQL 5.6.20 running (mostly just) a database with InnoDB tables is exhibiting occasional stalls for all update operations for the duration of 1-4 minutes with all INSERT, ...
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InnoDB says I'm in Deadlock when it should not be

I'll do my best to explain the situation. I'm at a complete loss. Preliminaries I'm running a Java Web Application in Tomcat 7.0 using a JDBC Connector to communicate with my MySQL Database. The ...
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12k views

Fastest way to check if InnoDB table has changed

My application is very database intensive. Currently, I'm running MySQL 5.5.19 and using MyISAM, but I'm in the process of migrating to InnoDB. The only problem left is checksum performance. My ...
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1answer
54 views

MySQL my.cnf: innodb_log_file_size is missing

How to set innodb_log_file_size to MySQL database if there is no innodb_log_file_size in my.cnf configuration file? I'd like to backup via Percona Xtrabackup and the backup crashes at this point ...
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53 views

is this dead simple query too slow?

I have added and removed a few indexes from my user table and, while testing, didn't see the performance gains I had hoped. As a result, I removed the indexes and tried a simple query to see what my ...
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See indices implicitly created for foreign key constaints in MySQL

When I add a foreign key constraint to my table, SHOW INDEX doesn't show any new indices, but the overall space used by the indices in that table increases. Apparently, the index for the field I put a ...
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43 views

innodb_buffer_pool & innodb_buffer_pool_instances

I have a database dedicated server with one quad-core cpu and 48GB Memory. Total database size is about 6GB and my ultimate goal is to get the maximum performance out of this system. At First, to ...
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Is it safe to delete the innodb schema on a new Amazon RDS instance?

As per the title, I'm struggling to find out if it's safe to delete the innodb schema that's created on a fresh Amazon RDS instance. mysql> SHOW DATABASES; +--------------------+ | Database ...
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How do you update a large MySQL table that's on a server?

I have an application on a web server. The PHP front end for the application queries a MySQL database which has a table that contains 60 million taken domain names. My application queries this ...
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2answers
196 views

show table name + number of records for each table in a mysql innodb database

How to list all tables in the current database, together the number of rows of the table. In other words, can you think of a query to come up with something like this in mysql? ...
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39 views

InnoDB compression: memory usage

InnoDB offers table compression for Barracuda-type tables and the recommendation seems to be to "adjust" buffer_pool_size. The documentation is rather vague about the definite impact of compression on ...
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43 views

How does subpartitioning actually work and what physical files are created?

I can't understand how the subpartitioning works in mysql. I am reading the following example: create table invoices ( customer_id int not null, product_id int not null, amount decimal ...
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994 views

Row size error with MySQL

I'm running a MySQL server on my Macbook (for testing). Version is 5.6.20 from Homebrew. I started running into "Row size too large" errors, and I've been able to reduce it down to this test case. ...
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395 views

Why are simple SELECTs on InnoDB 100x slower than on MyISAM?

I have quite an annoying problem. I want to use INNODB as my main database engine and give up on MyISAM as I need the former for using galera-cluster for redundancy. I copied (description follows) ...
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64 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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210 views

MySQL RDS Instance eating up memory and swapping

I have an issue with memory on a RDS instance which is of db.m2.4xlarge class. Below are the specifications of the RDS instance Instance Class: db.m2.4xlarge ( 68.4 GB of RAM ) Engine: ...
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82 views

InnoDB deadlock with INSERT .. SELECT

I am trying to understand why a deadlock occurs when two workers in parallel are running INSERT .. SELECT queries on a table which has both 1) auto incremented primary key, 2) a unique index on ...
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71 views

Innodb DB Consuming IO even when no operations are being done

I am currently doing some stress testing where I am pushing inserts to the database as fast as I can. The simulation inserts 10000 records per second. After inserting around 200 million records I ...
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57 views

MySQL Delete Rows from Slave

I want to truncate the majority of data on a slave such that it only has the most recent records. I'll eventually demote the current master, making it a read-only archive, and promote the truncated ...
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38k 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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67 views

MySQL DATE vs DATETIME read/write performace

Did anyone perform accurate read/write performance comparisons of MySQL's DATE vs DATETIME column types? Please do not bother writing "It should be faster" or "I think it's faster". I am looking for ...
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Cannot open table mysql/innodb_index_stats

After a fresh install of XAMPP and import from my linux live db that is working to the windows Dev-stage, I started encountering problems with INSERT. Everything else seems to work well. The errors I ...
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61 views

Copying datadir directory enough for backing up a database with InnoDB tables?

I have an innodb table with 80 million rows and it's extremely slow with mysqldump so I'm thinking of copying the datadir directory for a backup / transfer. I used to copy database with only MyISAM ...
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300 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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197 views

Revoke write privileges vs setting database to readonly

I am planning to do a database migration to a new server. During the transition stage, I do not want Apache user to be able to write anything to the database. I have two options. Revoke write ...
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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 ...
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85 views

Why is there no data loss with mysql innodb_flush_log_at_trx_commit set to 0?

Here is the MySQL info: mysql> show variables like 'innodb%flush%log%'; +--------------------------------+-------+ | Variable_name | Value | ...
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MySQL: What are the pros and cons of running with engine=Memory vs on a memory-mapped filesystem?

What is the difference (in terms of read and write perf, alter tables, backup and recoverability and consistency) of running a MySQL database on a memory-mapped filesystem vs with ENGINE=MEMORY
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29 views

select where index + other field

Learning indexing I have made an index, consisting of usergroupid and birthdate I understand that queries will then benefit from indexing when searching usergroupid and/or birthdate But what ...
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427 views

MySQL buffer pool usage + high load

We've got a quite powerful server: HP ProLiant DL360p Gen8, 2xIntel Xeon E5-2630 2.30GHz, 128GB of RAM. The whole data set should fit in memory: mysql> SELECT ...
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86 views

MariaDB ALTER TABLE produced a separate .ibd file, how can I re-integrate the data into the shared table space?

We have a multi-GB InnoDB MariaDB (recently switched from MySQL). For some reason, the value of innodb_file_per_table changed to ON (we wanted only one innodb data file explicitely). So when I ran an ...
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MySQL: Merge Same Database on Several Location into Single Location

I have registration form, which exactly same for several location. Each of them has REG column, which this field is unique for each row. Basically each data input have different REG number for it, ...
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1answer
64 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 ...
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1answer
38 views

Consistent backup of large DB --single-transaction

I need to mysqldump a large DB (330 GB) in order to set up a slave for replication. Does --single-transaction allow me to dump the entire DB without shutting mysql down and keeping it down for the ...
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86 views

Restoring data from dumped sql file gives: mysql: unknown option '--innodb_file_per_table

I was trying to separate DB indexes from ibdata1 I took the steps in what-is-the-best-way-to-reduce-the-size-of-ibdata-in-mysql I dumped data, dropped databases, and started mysql service. I got the ...
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70 views

hot/live sql backup

please excuse my ignorant question as I am still fairly new to database things so I have a mysql database and a part of it has file with average size of 10M I store them in their own directory and ...
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Is it possible to restore a database snapshot from a 64 bit system to a 32 bit one?

I would like to perform a restoration test on a snapshot backup of my MariaDB database using a test server running on a 32-bit OS. My production server is a 64-bit system. I would like to know if the ...
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124 views

MySQL consistent nonlocking reads vs. INSERT … SELECT

So, from my reading of the MySQL 5.5 documentation and some experiments I did with colleagues, I understand that the following is the case: With InnoDB tables, a simple SELECT statement (one that ...
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87 views

Finding the right MariaDB configuration

I’ve read several articles about how to configure MySQL/MariaDB, but now I’m kind of confused how to find the right values. Some articles suggest not choosing to high values, others recommend adapting ...