Reads though would not be blocked, ie there is no MYISAM like table lock priority problem with pending WRITE query blocks any READ queries to execute on the table. mysql> show processlist; +-------+------+-----------+----------+------------+------+------------------------------+------------------------------+-----------+---------------+-----------+ | Id | User | Host | db | Command | Time | State | Info | Rows_sent | Rows_examined …
- till's blog: Hosted MySQL: Amazon RDS (and backups)
…script" you'll many scripts ready for the task. Snapshots work best with InnoDB, with MyISAM you'll have to start the snapshot while holding a "flush tables with read lock" and the flush operation will take some time to complete.
Compression
ZFS can compress data on the fly and it is surprisingly cheap. In fact the best tpcc results I got were when using compression. I still have to explain this, maybe it is related to better raid controller write cache use. …
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- High Scalability: Paper: A Study of Practical Deduplication
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In some cases MyISAM is faster than InnoDB, but usually only when the buffer pool is cold. Please don't take away that you should be using MyISAM for everything! . MyISAM may be good for raw performance, but there are limitations which MyISAM imposes that are difficult to work with. MyISAM does not maintain checksum consistency during regular operations and is not ACID compliant. MyISAM and InnoDB may perform differently under concurrency, which this benchmark does not …
- A Fresh Cup: Double Shot #578
- Rails Envy » Home: RailsLab: Scaling Your Database - Part 2
- oldmoe: 101 Reasons Why PostgreSQL is a better fit for Rails than MySQL
- Simple thoughts - articles: The Internal Storage Mechanism For Globalize for Rails Model Translations
- Pennysmalls: Much faster Rails tests if you use MyISAM
- Scout ~ The Blog: One change that lowered our DB I/O by 80%
MyISAM
The MyISAM storage engine was the default prior to MySQL 5.5; it's main advantage is speed — however, this is at the expense of ACID compliance, transactions and row-level locking: all the features of InnoDB.
MyISAM uses table level locking, this means that during certain operations the entire table is locked from writes, causing potential concurrency issues.
One feature that MyISAM provides that no other (default) table engine supports is FULLTEXT indexes.
- MySQL Performance Blog: Sphinx 2.0.2 Beta is released, Sphinx Users Conference in December
- igvita.com: HandlerSocket: The NoSQL MySQL & Ruby
- James on Software: InnoDB kernel_mutex Contention and Memory Allocators
- New Relic: Better Metric Data Handling Improves New Relic's Performance
- till's blog: Hosted MySQL: Amazon RDS (and backups)
- Ruby-coloured glasses: Making views/triggers/functions work in mysql for rails
…replication for MySQL 5.1 and 5.5, and we will be finally switching the default engine from MyISAM to InnoDB before the year ends.
Database-less Environments
Environments with no relational database became available this year. Thanks to your feedback we were able to make this feature generally available for all customers and release a few recipes that allow you to connect to databases like RDS .
New Directions ... and Science!
We have a brand new Data Scientist …
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- giant robots smashing into other giant robots: This week in open source
- Riding Rails - home: Rails 3.1.2 has been released
- Paul Gross's Blog: Scaling PostgreSQL at Braintree: Four Years of Evolution
- WyeWorks Blog - The Team's Voice: Rails 4 compilation links
…catch developers off-guard when they added a connection to a MySQL database that used MyISAM (which doesn't support transactions) instead of INNODB (which supports transactions).
Persisting an ActiveRecord object in a place where it won't get rolled back or otherwise removed
Rspec and DatabaseCleaner are generally configured to roll things back that are created in the context of a test example. This also applies to code that is run in a before(:each) block. Developers expect …
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When a server reports data to Scout , a small bit of data is updated in a MySQL MyISAM table. Each of these updates doesn't change much data:
UPDATE `plugins` SET `last_reported_at` = '2010-11-17 19:53:00' WHERE `id` = 999999
I assumed that only the updated data was written to disk. I was wrong: Jesse Newland of Rails Machine pointed out that updating a row in a MyISAM table rewrites the entire row to disk (not just the updated columns).
- RailsTips by John Nunemaker: Mongo Scout Plugins
- Ruby on Rails Podcast: James Edward Gray II - Ruby on Rails Podcast
- Ruby Inside: New Relic RPM Officially Supports Rack and Sinatra - Finally!
- : Partner Thursday: Start monitoring your Servers in minutes with Scout
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- Lindsay Holmwood - auxesis' musings: The times, they are a-changin'
…and then finally got down to business and did a show create table my_table_name and whoa, it's MyISAM! That's not good. So I set this option in /etc/my.cnf : default-storage-engine = innodb
Restarted MySQL - what's this, it wouldn't start! Checked the logs: 100303 18:37:37 [ERROR] Unknown/unsupported table type: INNODB 100303 18:37:37 [ERROR] Aborting
Now we're getting somewhere. The clincher: mysql> show engines; +------------+---------+-----------------------------------------------------------+--------------+------+------------+ …
- MySQL Performance Blog: XtraDB storage engine release 1.0.6-9
- igvita.com: Measuring & Optimizing I/O Performance
- oldmoe: 101 Reasons Why PostgreSQL is a better fit for Rails than MySQL
- UK Ruby on Rails, Exalead, AWS, Consultancy - Bugmash! Comments: InfiniDB, InfoBright and MonetDB
- Home - Leading Ruby on Rails Development and Consulting firm in India - Vinsol: 11 Things to Consider Before Deploying Your Rails Application
- jystewart.net | notes, tips and commentary by James Stewart: Weekend Links
…durability, reduce sync delay. Closest comparison to the durability behaviour is MySQL's MyISAM.
Data is not written transactional, so if the server is killed during a write operation, the data is likely to be inconsistent or even corrupted and needs repair. Think classic file systems like ext2 or MyISAM.
In MongoDB 1.3 a database flush to disk can be enforced by sending the fsync command to the server.
Replication
Replication is the recommended way of ensuring data durability …
- Trevor Turk: Weekly Digest, 3-24-10
- paperplanes: An Inconvenient Caveat about MongoDB's Replica Sets
- Viget.com Blogs: RubyConf 2009 Recap
- Axon Flux // A Ruby on Rails Blog: How Superfeedr built Analytics using MongoDB
- Ruby Inside: Rackamole: Rack-Based Monitoring For Your Ruby Web Apps
- RailsCasts: Episode 194: MongoDB and MongoMapper
…exception_logger, hoptoad, exceptional or simply but log exceptions to a DB table ( protip: make that table MyISAM, otherwise exceptions that are added during a transaction will be removed when that transaction rolls back - duh ). Those exception notifications are great but they never provide a lot of context for how the user got to the point.
Lastly there is also the role that log files play in customer support. Have you ever gotten a complaint about data disappearing from your service? With …
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