InnoDB : MySQL's ACID-compliant Storage Engine

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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
2k 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 ...
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3answers
1k 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
102 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 ...
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1answer
978 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
6k 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 ...
4
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1answer
2k 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
5k 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? ...
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2answers
293 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 ...
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2answers
3k 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
473 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` ...
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1answer
3k 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
2k 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?
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1answer
6k 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
12k 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
244 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 ...
4
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1answer
9k 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 ...
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1answer
155 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 ...
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1answer
610 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 ...
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1answer
377 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
111 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
2k 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
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1answer
327 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
305 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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833 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
356 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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2answers
990 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 ...
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3answers
1k 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 ...
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1answer
663 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, ...
3
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3answers
13k 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 ...
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2answers
3k 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
4k 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 ...
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2answers
5k views

How to use GROUP BY after the Having clause Mysql

Here is the query which gets the accounts for a specific user the products are related to accounts in one-to-many relation so for each product there are four permissions All the accounts which is not ...
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0answers
34 views

How to add column/alter structure to big table in MySQL [duplicate]

'm php developer so dont be strict. I have a big table ~5.5gb dump. Our PM decided to make new column in it to perform new feature. Table is InnoDB So what i tried: Alter table in screen with table ...
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4answers
6k views

How to add column to big table in MySQL

I'm php developer so dont be strict. I have a big table ~5.5gb dump. Our PM decided to make new column in it to perform new feature. Table is InnoDB So what i tried: Alter table in screen with table ...
2
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1answer
311 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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1answer
782 views

Is there a system wide way to change MariaDB to create tables using ROW_FORMAT = DYNAMIC

I've got a 700MB dump file from a mysql database that I was trying to undump into a new install of MariaDB and I got this error ERROR 1118 (42000) at line 7481: Row size too large (> 8126). ...
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53 views

Federate engine to help overcome distributed transaction?

Currently we have been using pure innodb. The issue is that we have architecture where we have multiple outlet each have its own local db and a copy of it in the hq outlet. The issue is that we ...
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1answer
241 views

how important are mysql's innodb logs?

I'm basically concerned about the following two settings, these are my default settings : innodb_log_buffer_size 1048576 innodb_log_file_size 5242880 I haven't changed them for 2 reasons : one, ...
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1answer
852 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 ...
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1answer
389 views

MySQL import LOCK doesn't prevent PRIMARY key issues

I am using Django and only want to backup mysql data (not it's structure; Django will do that, and it will otherwise mess up Django-South's migration checks). Some info; my tables are almost all ...
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2answers
415 views

Convert the table PROCESSLIST from InnoDB to MYISAM

I use MySQL. My database's name is "db", and I have a table called "Test". I want recover the last update, so I used this query: SELECT update_time FROM information_schema.tables WHERE ...
3
votes
1answer
12k views

How can extract the table schema from just the .frm file?

I have extracted the data directory of mysql from a backup and need to get the schema from an old table, however it's a backup from a different machine. I have read a fair number of tutorials today ...
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1answer
109 views

MySQL HDD activity with empty process list

What does this mean and how can I understand what is mysql doing? I use InnoDB, my database is huge. This happens when I disconnect my app. Thanx.
2
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1answer
79 views

Which hardware you suggest?

I'm completely new to buying a database hosting and I would greatly appreciate your opinion about the following situation. I just created an App and I want to go live this weekend. I want to be ...
0
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1answer
2k views

InnoDB tables inaccessible after reboot

After reboot each time, I can't see my InnoDB table. However, when use command mode I can see my tables, but cannot access to it. mysql> show tables; +----------------------+ | ...
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2answers
433 views

mysql innodb_flush_log_at_trx_commit clarification

I have been reading up on innodb as a storage engine, mainly because I have recently moved to AWS and they do not recommend myISAM which my databases current run on (and have for about 10 years) So ...
3
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1answer
443 views

mysqldump freezing on a specific table

I dumped a database (sys_data) which is very big (800GB, all data in one ibdata file) from a remote server. But the dump was blocked at a table (tb_trade_376). My dump command: mysqldump -uxx -pxx ...
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1answer
974 views

MySQL - Export two columns from large table without causing a lock

I am a sysadmin who doesn't do a ton of dba stuff. For a project, I have access to a production server--which I am not the sysadmin for--with an enormous 40,000,000 row >10 GB MySQL InnoDB table. I ...
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1answer
2k views

MySQL dynamically optimize innodb tables without “file per table” setting

We are getting a “too many connections” error once a week the same time a mysql procedure runs. The procedure runs “optimize table” on hundreds of tables and takes nearly ten hours to finish, taking ...