Thanks to a patch Dane Miller submitted, MySQL Heartbeat can now be used to monitor Slony-I replication lag for PostgreSQL. It works identically: it updates a record on the master and looks for it on the slave. You just have to specify the database driver on the command-line:
mysql-heartbeat [options] --dbidriver=Pg
Most of the tools in the MySQL Toolkit are very MySQL-specific. This one just happened to be an exception, and I'm happy it's useful for more than the original purpose.
We were using replication to deal with certain queries that were producing table scans. I realize this is not a great long term solution but we were migrating a web site that was set up this way, so it wasn’t really a choice.
We had a database that was a mix of InnoDB and a few MyISAM tables. The MyISAM tables were used for fulltext searches.
To get a database dump, we were using the command
mysqldump --all-databases --single-transaction
--master-data=1 > dumpfile.sql
We’d then import the dump into a DB slave. When we’d bring a slave up and reply the log, we’d get a duplicate key error. After a few times, we noticed it was always on the MyISAM table. This is because MyISAM does not use transactions, and –single-transaction does not place a read lock on tables. Data can be inserted into the table during the backup but before that table is dumped.
In conclusion, if you’re using …
[Read more]It’s been a long time since we’ve started this project and it is time to make a checkpoint. So, I’ve decided to release final 1.0 version and make 1.X branch stable while all serious development with deep architectural changes will be done 2.X branch (trunk at this moment).
Changes from previous release:
Very fast, as it turns out. Click through to the full article for details.
Recently I wanted to setup a little MySQL sandbox where I could hack away at MySQL with reckless abandon.? A sandbox is different than a test environment, it’s usually one which is very breakable.? You want to be able to break things, or rather take them completely apart and put them back together.? It’s the only way to understand all of the moving parts.
So searching google, I happened upon Giuseppe Maxia’s Replication Playground. It basically installs into an unprivileged directory, one master, and three slaves.? You can then test out various scenarios. Read his blog entry.
It is trivial to install, however I encountered some issues with MySQL 5.0, which caused me some troubles.? I sent him my feedback, and comments, and it looks like he has …
[Read more]
As I wrote a few days ago, I'm writing the replication chapter for the second edition of High
Performance MySQL. I'm writing about replication filtering
rules right now, and I thought it would be good to get input on
this. If you have favorite replication filtering tricks you'd
like to share, or tasks that always frustrate and/or confuse you,
please post them in the comments. I'm making a section that shows
how to accomplish common filtering and rewriting needs, such as
preventing GRANT statements from replicating to the
slaves.
Thanks very much! I hope the community involvement will make this book more useful for everyone.
Continuing in the tradition, which I hope has been as helpful to you as it has been to me, I'm opening the floor for suggestions on chapter 9 of the upcoming High Performance MySQL, Second Edition. Unlike the other chapters for which I've listed outlines, this one isn't substantially written yet. It's in detailed outline form at this point (a tactic that has worked very well for us so far -- I'll write about that someday).
I'm trying to get feedback much earlier in this chapter's lifecycle, for several reasons. Two of the most important are that this is one of the first chapters I've had a chance to really take from scratch, and the chapters I haven't written from scratch have been harder to organize, as you've probably seen from the last few outlines I posted. There's a lot of value in working top-down on this deep encyclopedia-style material.
Read on for the outline and more thoughts I just can't keep to myself.
One of MMM users reported that they’re experiencing really weird memory leaks in checker processes used by MMM. After a deep investigation I’ve found out that Perl part of the checker and checker modules does not leak (at least I didn’t found these leaks), so I think it could be caused by some problems in MySQL DBD module (client uses Ubuntu server).
So, I’d like to ask all users to check if their checker processes use more memory than expected and if yes, what OS, MySQL libraries versions and Perl version used on their servers.
Thanks in advance for any help.
I am considering taking some time off work to concentrate deeply on MySQL Table Sync, which has been getting usage in very large companies whose names we all know. There are a lot of bugs and feature requests outstanding for it. It is overly complex, needs a lot of work, and I can't do it in one-hour or even three-hour chunks. I need to focus on it. I'm considering asking for a bounty of $2500 USD for this. Please let me know what you think of this; it seems to be a successful way to sponsor development on some other projects, like Vim.
For the amount of time I think this will take, $2500 is far below my per-hour consulting rate; I considered setting the bounty higher, but I think this will be a fair amount.
I would not begin this project before December at the earliest, so there's some time to raise funds and time for me to continue working on High Performance …
[Read more]MySQL Parallel Dump can now dump a single table simultaneously into many files of a user-specifed size. This not only helps speed dumps, but it paves the way for much more efficient parallel restores. Read on for the details.