InnoDB : MySQL's ACID-compliant Storage Engine

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886 views

How to prevent “ibdata files do not match the log sequence number”?

I am dealing with a very large set of databases that are all innodb. I've enountered this on mysql restart too many times for my comfort: ibdata files do not match the log sequence number But I've ...
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1answer
269 views

Deadlock from mysqldump --single-transaction, is it possible?

Is it possible to get a deadlock if you ran mysqldump with the argument --single-transaction ? or any other complication ? If it is used to backup a live site with many other querys running at the ...
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0answers
322 views

Incorrect information in .frm file after a power outage?

CentOS release 6.3 (Final) x86_64 mysql Ver 14.14 Distrib 5.5.31, for Linux (x86_64) using readline 5.1 SHOW SLAVE STATUS\G: Slave_IO_Running: Yes Slave_SQL_Running: No ...
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1answer
5k views

What is causing Waiting for table level lock errors?

We got the database hanging twice already and trying to find a cause. show processlist Waiting for global read lock | INSERT INTO {myisam_table} ... In here the disk space was full so we thought ...
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0answers
402 views

MySQL InnoDB slow inserts

I'm currently struggling with an MySQL Community Server 5.5.27 when inserting large numbers of rows into a table. We're running a 24 core Intel Xeon machine with an SSD software raid array. I did some ...
2
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1answer
317 views

MySQL Performance Issues

Over the past 3 weeks we have been having bottle-necking issues at our MySQL server. I have been using MonYOG to watch the processlist in an attempt to get a grasp on the issues. We are aware that ...
2
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1answer
1k views

Recover the disk space after deleting rows from table

I deleted millions of rows from one of the table with innodb engine. I know that I need to run optimize table to recover the space. But running that will cause lock on the table, which will affect the ...
2
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1answer
247 views

MySQL / Fusion IO Configuration Question

I need a little configuration optimization. I think what I have is pretty good but feel like there's still room for improvement. Current Config [mysqld] user=mysql datadir=/var/lib/mysql ...
3
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1answer
300 views

Finding swap causes of MySQL

In my centos 6.3 server I have a MySQL 5.5.33 database. It has 17 tables (15 InnoDB, 2 MyISAM) and total records 6.7M rows. I refactored my schemas and added indexes for my slow logs. My average query ...
2
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2answers
439 views

Setting innodb_buffer_pool_size in for Mysql

We have a dedicated DB box with with 8 GB of RAM and running Redhat linux 64 bit OS. Our MySQL Data + Index size almost 7.8 GB. About setting innodb_buffer_pool_size, I have read 2 suggestions Set ...
6
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4answers
6k views

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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1answer
1k views

What happens if the mysql database's innodb log files are lost?

What I did was /etc/init.d/mysql stop then removed the files: ib_logfile0, ib_logfile1 then modified my.cnf file, variable: innodb_log_file_size and then: /etc/init.d/mysql start and allowed ...
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3answers
4k views

Why does MySQL ignore the index even on force for this order by?

I run an EXPLAIN: mysql> explain select last_name from employees order by last_name; +----+-------------+-----------+------+---------------+------+---------+------+-------+----------------+ | ...
2
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1answer
88 views

Why isn't the rows of an EXPLAIN accurate?

I have the following table: mysql> select count(*) from employees; +----------+ | count(*) | +----------+ | 10000 | +----------+ 1 row in set (0.03 sec) I do an EXPLAIN: ...
2
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2answers
523 views

How do I determine how much data is being written per day through insert, update and delete operations?

The longevity of SSDs is largely determined by the amount of bytes written by insert, update and delete operations. What is the best way to accurately determine how much data is being written by ...
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3answers
750 views

Backup / Export data from MySQL 5.5 attachments table keeps failing!

Can anyone please help! - I have a large table in a MySQL 5.5 database. It is a table which holds a mixture of blobs/binary data and just data rows with links to file paths. It has just over a million ...
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0answers
84 views

Any drawback to lots of creating and renaming tables at InnoDB?

I'm trying to optimize an important cronjob for my program, and what it basically does is generate a long list of user ids with their score points. I have a table called user_ranks and it will bulk ...
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1answer
237 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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1answer
76 views

Increased server load after InnoDB deadlock

I am using InnoDB instead of MyISAM for a couple of months right now, and it has really optimized my game database-wise. I was aware of the danger of deadlocks, but hadn't had any problems with it, ...
2
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1answer
698 views

InnoDB: Error: pthread_create returned 12

have installed MySQL in a particular folder. I was able to run the server and create accounts, databases etc. However, now whenever I try to start the server, I get an error: $ mysqld_safe ...
2
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0answers
277 views

Insert Speeds for large batches

In my application, my INSERTs seem to be taking a major chunk of the time. I have a large number of objects in memory (~40-50,000) which i want to insert into a table. Lets take a sample table ...
2
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1answer
81 views

Why is it slower to access records at the end of the database?

I have a mysql innodb database running with some 200k records, and I'm having some unexpected slowdown when accessing records near the end of the database. Specifically, it is taking .10 seconds to ...
3
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1answer
363 views

How to convert innodb engine tables to tokudb engine

Hi I want to migarate my server newly installed tokudb engine. i want to convert each table of database from innodb to tokudb. How can I do that using sed command ?
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2answers
3k views

MySQL 5.5 High CPU Usage

I have been working with a client with high traffic website(500k visitors and 600-800 active users at any given time). This uses wordpress and the DB is using MyISAM engine. The problem we had was ...
3
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1answer
332 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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3answers
2k views

Transaction Rollback on DROP DATABASE

Does MySQL use transactions for DROP DATABASE... statement (all tables use InnoDB engine)? Basically I would like to know if any data will be lost if I kill DROP DATABASE... query while it's running? ...
2
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2answers
167 views

Specific disadvantages to storing infrequently accessed large files in a large database

I have heard many times across the web that it is, for various reasons, a bad idea to store files directly in a database, the preferred method being to store filenames in the database, and files ...
0
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2answers
1k 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 ...
2
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1answer
224 views

InnoDB, Hash Table, Reference Table and Fragmentation

I have a big list of domains and URLs that I store in a database, there are around 150M domains and 300M URLs, I'm using InnoDB to store each in the format: CREATE TABLE IF NOT EXISTS `domains_list` ...
0
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1answer
848 views

Putting a Select statement in a transaction

What is the difference between these 2 queries: start transaction; select * From orders Where id=1; UPDATE orders SET username="John" Where id=1; commit; And without transaction: select * From ...
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2answers
924 views

Remove InnoDB files (ibdata1 and iblog files) after migration to MyISAM

I changed the only two InnoDB tables on a replication slave to MyISAM, so the slave now only has MyISAM tables. Can I now remove the ibdata1 file completely?
3
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1answer
3k views

InnoDB log sequence number is in the future

130711 23:03:40 InnoDB: Error: page 23 log sequence number 3336825872455 InnoDB: is in the future! Current system log sequence number 235089. InnoDB: Your database may be corrupt or you may have ...
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3answers
4k views

How to estimate/predict data size and index size of a table in MySQL

I am finding what is the best way to estimate size of a table for that i have studied lot of blogs and forums but unable to find any accurate answer For an example we have a table City with InnoDB ...
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1answer
138 views

Query mysql database through memcache

I have been trying to use memcache with MySQL 5.6 but I can not figure out how to do this. I have add an entry into innodb_memcache.containers so I can query the database through memcache. What I ...
2
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1answer
3k views

MySQL: Row size too large (> 8126)

Here's the issue. I have a table which has 300 columns in it, each up to 255 bytes (there IS a business justification for this). When I try it create it using VARCHAR(255), I go past the limit for ...
3
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1answer
121 views

What if I want to keep using MyISAM

In my current use of MyISAM the databases are extremely small and kept for a few weeks after which time they are deleted and completely rebuilt with a clean slate. The script uses MYISAM tables and ...
2
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1answer
248 views

List of variable defaults for InnoDB engine

I would like to list the defaults for the global variables that are innodb specific. The problem is that the following commands doesn't list any innodb variables: /usr/sbin/mysqld --no-defaults ...
2
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0answers
178 views

InnoDB forum DB design and Composite Primary Key (Cluster Primary Key)

I am designing forum database using InnoDB and got few questions , Could any one please help me to clarify them? Posts and Comments table design below CREATE TABLE `my_posts` ( `forum_id` ...
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1answer
84 views

InnoDB query duration inconsistent

I am running a series of UPDATE commands on a nearly empty InnoDB table, and around 1 out of every 20-30 queries will inexplicably take 10 times as long as the others. For example, the first 20 ...
3
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1answer
577 views

What is log sequence number ? How it is used in MySQL?

Can anybody give an example or scenario of log sequence number(LSN) used in MySQL
0
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1answer
250 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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1answer
165 views

I have accidently deleted ibdata1 on an ubuntu server

I have accidently deleted the 'ibdata1' file on the server having innodb, Is there any way I can recover it? the mysql service has restarted since the deletion.
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0answers
501 views

MySQL always crash on start, ibdata1 bigger than 4GB

I'm having a problem with MySQL when testing my production data. Whenever I started MySQL (mysqld), it always crash. My suspect is on my InnoDB data file (ibdata1) since the size is already bigger ...
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1answer
188 views

Implementing a Record Keeper/Rollback System for a MySQL Database

What's the best way to create a record keeping table for all actions in my database? I have a number of tables inside one database and I want to create another that records all movements in every ...
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1answer
278 views

Mysql Deadlock on update query on same row

My server is experiencing occasional deadlocks on two update queries on same row both using index (primary key). The conflicting queries are: UPDATE auth_user SET rep_score=185 WHERE ...
0
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3answers
373 views

MySQL InnoDB Sorting Issue

I was surprised to see MySQL's InnoDB showing an interesting behavior, which I cannot fully explain. According to the official MySQL InnoDB Documentation: "All indexes other than the clustered ...
0
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1answer
386 views

MySQL query optimizer ignoring smaller scan on TIMESTAMP column, cardinality?

I've got a complex multi-join query where the optimizer won't pick an index on a TIMESTAMP column even though it results in a smaller index/table scan. If I force the index on the TIMESTAMP column, ...
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2answers
5k views

MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: CentOS 5.9 24gb Ram 8 ...
2
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2answers
1k views

Optimizing mysql queries running on 50 million rows

Is there any technique/advice in order to optimize the performance of the queries below? According to my needs, my average db size will be approximately 30mill. rows per day, so every second less, ...
0
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1answer
2k views

The InnoDB log sequence number is in the future

Our site was getting intermittent database errors and I asked my webhost to check what's happening. After some inspection they found that the database has few issues and tried repairing it. Finally I ...