English
| Showing entries 1 to 17 |
I’ve been noticing an undeniable trend in my consulting engagements in the last year or so, and when I vocalized this today, heads nodded all around me. Everyone sees a growth in the number of cases where otherwise well-optimized systems are artificially limited by InnoDB contention problems.
A year ago, I simply wasn’t seeing the need for analysis of GDB backtraces en masse. These days, I’m writing custom tools to gather and analyze backtraces. A year ago, I simply looked at the SEMAPHORE section of SHOW INNODB STATUS. These days I’m writing custom tools to aggregate and reformat that data so I can interpret it more easily. And I’m actually seeing cases of this type of problem multiple times every week. I remember the first time I ran into a server that was literally optimized to the limit, but struggling under the load. It
[Read more...]
This Thursday (September 24th, 14:00 UTC), Heikki Tuuri, the father of InnoDB, will give a session on Concurrency Control: How It Really Works. He'll describe how InnoDB manages concurrency control, so that the system protects data integrity. Beginning with the basics of transaction management, Heikki will include a discussion of the ACID (atomicity, consistency, isolation, and durability) properties, and explain various transaction modes, locking, deadlocks, and more advanced topics such as the impact of next-key (gap) locking, referential integrity, XA (distributed transaction management) support, and more. While the discussion will focus on the
This Thursday (September 24th, 14:00 UTC), Heikki Tuuri, the father of InnoDB, will give a session on Concurrency Control: How It Really Works. He'll describe how InnoDB manages concurrency control, so that the system protects data integrity. Beginning with the basics of transaction management, Heikki will include a discussion of the ACID (atomicity, consistency, isolation, and durability) properties, and explain various transaction modes, locking, deadlocks, and more advanced topics such as the impact of next-key (gap) locking, referential integrity, XA (distributed transaction management) support, and more. While the discussion will focus on
This Thursday (September 24th, 14:00 UTC), Heikki Tuuri, the father of InnoDB, will give a session on Concurrency Control: How It Really Works. He'll describe how InnoDB manages concurrency control, so that the system protects data integrity. Beginning with the basics of transaction management, Heikki will include a discussion of the ACID (atomicity, consistency, isolation, and durability) properties, and explain various transaction modes, locking, deadlocks, and more advanced topics such as the impact of next-key (gap) locking, referential integrity, XA (distributed transaction management) support, and more. While the discussion will focus
This is sort of a self-documenting post, and a self-support group about ill-behaved tomcat apps.
Sometimes, you have multiple nodes accesing your MySQL server (or any kind of server, for that matter) concurrently. Eventually, software in one or more of these nodes might do nasty things (you know who you are buddy:))
MySQL provides a built in mechanism to limit concurrent connections, but this can only be set for the whole server, or on a per user basis. Unfortunatly, most of these setups use the same database user for all their nodes, so this feature can’t be used to confine any possible damage.
Enter your good friend iptables.
This isn’t perfect, but this little trick might help you while programmers take care of their business:
iptables -A INPUT -p tcp -m recent --rcheck --seconds 60 -j REJECT iptables -A INPUT[Read more...]
+0 
-0
One interesting and useful paper on real-world concurrency by Bryan Cantrill and Jeff Bonwick.
Abstract: In this look at how concurrency affects practitioners in the real world, Cantrill and Bonwick argue that much of the anxiety over concurrency is unwarranted. Most developers who build typical MVC systems can leverage parallelism by combining pieces of already concurrent software such as database and operating systems (i.e., concurrency through architecture), rather than by writing multithreaded code themselves. And for those who actually must deal with threads and locks, the authors include a helpful list of best practices to help minimize the pain.
+0
-0
One interesting and useful paper on real-world concurrency by Bryan Cantrill and Jeff Bonwick.
Abstract: In this look at how concurrency affects practitioners in the real world, Cantrill and Bonwick argue that much of the anxiety over concurrency is unwarranted. Most developers who build typical MVC systems can leverage parallelism by combining pieces of already concurrent software such as database and operating systems (i.e., concurrency through architecture), rather than by writing multithreaded code themselves. And for those who actually must deal with threads and locks, the authors include a helpful list of best practices to help minimize the pain.
Well, it took us a little while (we’ve been busy 
!), but we’ve now posted our presentations on InnoDB from the MySQL Conference and Expo 2009. You can download these presentations by Heikki Tuuri, Ken Jacobs and Calvin Sun from the InnoDB website, as follows:
Some months ago, Google released a patch for InnoDB that boosts performance on multi-core servers. We decided to incorporate the change into the InnoDB Plugin to make everybody happy: users of InnoDB don’t have to apply the patch, and Google no longer has to maintain the patch for new versions of InnoDB. And it makes us at Innobase happy because it improves our product (as you can in this post about InnoDB Plugin release 1.0.3).
However, there are always technical and business issues to address. Given the low-level changes in the patch, was it technically sound? Was the patch stable and as rock solid as is the rest of InnoDB? Although it was written for the built-in InnoDB in MySQL 5.0.37, we needed to
[Read more...]That should read “Talks, Talks, Talks” … There will be several presentations by InnoDB experts at the upcoming 2009 MySQL Conference and Expo. Whether you’re a newbie or an experienced DBA deeply familiar with InnoDB, you won’t want to miss these important talks about InnoDB:
Why should you care about the latest “early adopter” release of the InnoDB Plugin, version 1.0.3? One word: performance! The release introduces these features:
These new performance features can yield up to twice the throughput or more, depending on your workload, platform and other tuning considerations. In another post, we explore some details about these changes, but first, what do these enhancements
[Read more...]tl;dr: The MySQL community rocks. Percona, XtraDB, Drizzle, SSD storage, InnoDB IO scalability challenges.
For anyone who lives and dies by MySQL and InnoDB, things are finally starting to heat up and get interesting. I’ve been banging the “MySQL/InnoDB scales poorly” drums for years now, and despite having paid Enterprise licenses, I haven’t been able to get anywhere. I was pretty excited when Sun
[Read more...]
Here you can see that the gain is over 60% for 32 or more concurrent threads. Both results show the performance with the newly optimized version of PBXT. The test is running on a 2.16 MHz dual core [Read more...]
The reason is that isolation between concurrent transactions cannot be guaranteed, meaning that two concurrent transactions are not guaranteed to be serializable (the result of a concurrent transaction that has committed can "leak" into an ongoing transaction). Since they are not serializable, it means they cannot be written to the binary log in an order that produce the same result on the slave as on the master.
However, when using row-based replication they are serializable, because whatever values are written to the tables are also written to the binary log, so if data "leaks" into an ongoing
[Read more...]| Showing entries 1 to 17 |
