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Showing entries 1 to 30 of 53 Next 23 Older Entries

Displaying posts with tag: open query (reset)

Open Query on Twitter/Identi.ca
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Open Query now has its own @openquery account on Twitter and Identi.ca so you can conveniently follow us there for announcements and tips – and also ask us questions! All OQ engineers can post/reply. The OQ site front page also tracks this feed.

Previously I was posting from my personal @arjenlentz account with #openquery hashtag, but that’s obviously less practical.

6to4: Easing the IPv6 transition
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With the exhaustion of IPv4 address space looming sometime in 2012; probably earlier rather than later, it makes sense to ease on into IPv6 land.  Without straying into tunnel broking and endpoint shenanigans 6to4 is a method of wrapping up IPv6 inside of IPv4.

(note that MySQL does not currently support IPv6 itself – but what we’re discussing here is about externally facing systems, like your web/application servers)

6to4 performs three functions:

  • Allocates an IPv6 address block to any host/network that has a global IPv4 address.
  • Wraps up IPv6 packets inside IPv4 packets for transmission over IPv4 using 6in4 (traffic is sent over IPv4 inside IPv4 packets whose IP headers have the IP protocol number  set to 41; IPv6-in-IPv4. ) 
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    Business insight from the MySQL Conference 2010
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    At this year’s conference, I was pleasantly surprised with the high level of interest in Open Query’s proactive services for MySQL and MariaDB, and specifically our focus on preventing problems, while explicitly not offering emergency services.

    I’ll describe what this is about first, and why I reckon it’s interesting. When you think about it, most IT related support that includes emergency (24×7) operates similar to this:

    You have a house that has the front and back doors wide open with no locks, and you take out an insurance policy for the house contents. After a short time you call the insurance company “guess what, the most terrible thing happened, my TV got stolen.” Insurance company responds “that’s dreadful, you poor soul, let us fix it all up for you with getting a new TV and installing it.

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    Open Query @ MySQL Conf & Expo 2010
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    Walter and I are giving a tutorial on Monday morning, MySQL (and MariaDB) Dual Master Setups with MMM, I believe there are still some seats available – tutorials are a bit extra when you register for the conference, so you do need to sign up if you want to be there! It’s a hands-on tutorial/workshop, we’ll be setting up multiple clusters with dual master and the whole rest of the MMM fun, using VMs on your laptops and a separate wired network. Nothing beats messing with something live, breaking it, and seeing what happens!

    Then on Tuesday afternoon (5:15pm, Ballroom F), Antony and I will do a session on the 

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    Visiting Monty HQ
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    On this big trip, I made particular effort to finally visit Monty at his home near Helsinki. Somehow, in all my years at MySQL AB, this never happened – a sad omission. So, I spent the Easter days with Monty, Anna and now 5yo Maria.

    I’m not a fan of most meetings, and in many cases in-person meetings are not actually necessary to get things organised or done, but I think this was both most enjoyable as well as productive for our respective businesses and joint interests. Good company, discussion, food, drink, sauna… fabulous.

    It’s a great pity we live on opposite sides of the planet, as we do get along very well together. We definitely don’t agree on everything, but we’re always absolutely direct with each other, and try to provide good arguments whenever we disagree, to explore things further.

    Ken Jacobs leaves Oracle
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    Matt Asay writes today in Oracle loses some MySQL mojo about Ken Jacobs leaving Oracle. For me, that’s a major bummer. Ken has been a long-time visitor of the MySQL Conference and that’s where I first met him: a friendly and knowledgeable person, on database technology in general but also about MySQL. When Innobase Oy got bought by Oracle, InnoDB got placed under Ken’s leadership and did pretty well there. We’d occasionally exchange emails, and I’ve always found him to be responsive and helpful.

    I think it was kinda presumed by people that the technical part of MySQL at Oracle would also reside with Ken. Obviously now, that’s not going to be the case. What that means exactly, I don’t know as I am not familiar with the other person (Edward Screven). We’ve got to

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    Friendlist Graph Module for Drupal
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    At DrupalSouth 2010 (Wellington) after LCA2010, Peter and I implemented a Drupal module as a practical example of how the OQGRAPH engine can be used to enable social networking trickery in any website. The friendlist_graph module (available from GitHub) extends friendlist, which implements basic functionality of friends (2-way) and fans (1-way) for Drupal users.

    The friendlist_graph module transposes the friendlist data using an OQGRAPH table, allowing you to query it in new and interesting ways. By adding some extra Drupal

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    Petition for MySQL consideration in Oracle+Sun merger
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    MySQL requires special consideration in the Oracle+Sun merger, otherwise both Oracle and MySQL users and vendors will literally pay the price. If you agree, please sign this petition now.

    To be very clear, Open Query is in favour of the merger, we feel that overall it’s a good fit. We would also like to see it happen quickly, as obviously this is best for Sun employees and clients, as well as Oracle’s broad business prospects.  Read more

    The Future of MySQL (EU Crunch Time)
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    You’ve probably seen Monty’s post Help Saving MySQL. This is about

  • Development (will Oracle put significant effort into MySQL, actually innovating)
  • Brand (”MySQL” has a huge footprint), the trademark owner can enforce this – there have already been issues with companies offering MySQL related services via Google AdWords not being able to use the word MySQL in their ad text even though it was correctly used as an adjective.
  • Forking is fine, but still has to deal with the branding. For MySQL, that’s possibly the most significant issue of any OSS product ever encountered. You’re not competing against a company, but against an existing brand footprint that you (because of the trademark) have to steer clear of. So “just fork it”
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    OQGRAPH at OpenSQL Camp 2009, Portland
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    Antony is travelling up to Portland for this great event that’s about to start Fri evening and going over the weekend. He’ll be showing other devs and people more about the OQGRAPH engine, and gathering useful feedback.

    Open Query is, together with many others (I see Giuseppe, Facebook, Gear6, Google, Infobright, Jeremy Cole, PrimeBase Technologies, Percona, Monty Program, and lots more), sponsoring the event so that it’s accessible for everybody – reducing the key factor to getting there rather than having to worry about high conf fees.

    Having acquired the world’s biggest jetlag flying to Charlottesville VA for last year’s OpenSQL Camp, I can confirm from personal experience that it’s a great event. While I can’t be there this time, I’m looking forward to hearing all about it!

    OQGRAPH session on MySQL University – recording now available
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    It was fun doing the MySQL University session on OQGRAPH yesterday. Now also available: slides (PDF) and audio/video recording (FLV download, if anyone can convert to a more open format, that’d be great).

    The search for MySQL 5.5
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    So, MySQL 6.0 was ditched, and a few weeks ago 5.4 was also – its features to be added in other (earlier) versions (I’m told 5.2 but not sure). I reckon that’s good news, regardless of the version number. There was also an announcement about a change in the release mechanism at Sun/MySQL.

    Now for practicals. If I look on Launchpad, the 5.1 branch is the only active one (next to 5.0 fixes, of course). 5.4 was last updated 15 weeks ago. There is no 5.2 on there that I can find. Wasn’t looking for it really, just happened to notice its absence while I was trying to find 5.5. And the reason for that was that Miguel closed a bug I was following, noting it was no longer reproducible in 5.5. He pastes some code that reports mysql as 5.5, so it’s not a

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    OQGRAPH engine on MySQL University – 5 Nov 2009 10:00 UTC
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    Only a few weeks after Walter’s session on Multi-Master Replication with MMM and thanks to the great gang at MySQL Docs (my colleagues from long ago!) I’ll be doing a MySQL University session in a few days, about the GRAPH computation engine. From talks/demos I’ve done about it so far, I’ve learnt that people love it but there are lots of interesting questions. After all, it’s a pretty new and in a way exotic thing.

    MySQL University uses DimDim, an online presentation service. You’ll see slides, and hear my voice. You can also type questions in a live chat room. We actually even got desktop sharing working so a live demo is possible, we’ll see how that goes on the day (I’ll make sure to

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    MariaDB 5.1 packages for Debian/Ubuntu
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    See the OurDelta blog for details of this release. RHEL/CentOS packages also coming.

    thread_stack_size in my.cnf
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    Many configs have thread_stack_size configured explicitly, but that can cause rather bad trouble:

    • if the stack inside a thread it’s too small, you can get segfault crashes (stack overflow, essentially). Particularly on 64-bit.
    • if the stack is too large, your system cannot handle as many connections since it all eats RAM.

    Let mysqld sort it out, on startup it does a calculation based on the CPU architecture, and that’s actually the most sensible. So for almost all setups, remove any thread_stack_size=… line you might have in my.cnf.

    Trivia: identify this replication failure
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    We got good responses to the “identify this query profile” question. Indeed it indicates an SQL injection attack. Obviously a code problem, but you must also think about “what can we do right now to stop this”. See the responses and my last note on it below the original post.

    Got a new one for you!

    You find a system with broken replication, could be a slave or one in a dual master setup. the IO thread is still running. but the SQL thread is not and the last error is (yes the error string is exactly this, very long – sorry I did not paste this string into the original post – updated later):

    “Could not parse relay log event entry. The possible reasons are: the master’s binary log is corrupted (you can check this by

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    OQGRAPH on Launchpad, graph examples
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    The MySQL 5.0 and MySQL/MariaDB 5.1 source code is now also available through Launchpad. If you were waiting for a version for 5.1 and are ok with building the plugin from source, now you can!

    The repo contains a subdir for examples, we’re hoping many people will contribute little snippets and scripts to import and use interesting datasets. To give you a hint, with graph capabilities you are able to deal with RDF data sources. You just need to transform the XML to say CSV, import into a suitable structure, and copy the edge information across to an OQGRAPH table.

    Roland Bouman’s tree-of-life (which uses xslt stylesheets) are a good example of that approach, and was the first entry in the examples tree,

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    GRAPH Engine Linux binaries in MySQL 5.0.86-d10 available now
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    At this point we have a 32-bit and a 64-bit Linux binary tarball, should work on most Ubuntu and CentOS and the like (I tested a few). Possibly OSX coming. Not sure on Windows right now.

    For further details and download links, see yesterday’s release post.

    GRAPH Engine source in MySQL 5.0.86-d10 available now
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    It’s time to play! A special thanks particularly to Antony Curtis for the excellent smart and actually very speedy coding, and for just being a great guy to work with. If you would like to utilise his ace MySQL knowledge and coding skills, do talk to me!

    Right now, we have a source tarball available for you, patching OQGRAPH on top of a MySQL 5.0.86-d9-Sail (OurDelta) source. As you know MySQL 5.0 does not have engine plugins so patching is the only way we can put it in. This OQGRAPH codebase is licensed under GPLv2+.

    Even though we’ve successfully built it on several platforms and architectures, since this is the first public release we’d like you to try it first, as we’re sure that there might be problems on some platforms. When we catch and fix those, we can do proper

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    MySQL University session Oct 22: Dual Master Setups With MMM
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    This Thursday (October 22nd, 13:00 UTC), Walter Heck (of Open Query) will present Dual Master Setups With MMM. MMM (Multi-Master Replication Manager for MySQL) is a set of flexible scripts to perform monitoring/failover and management of MySQL master-master replication configurations (with only one node writable at any time). Session slides (PDF).

    The toolset also has the ability to read balance standard master/slave configurations with any number of slaves, so you can use it to move virtual IP addresses around a group of servers depending on whether they are behind in replication. For more
    information, see mysql-mmm.org.

    For MySQL University sessions you point your


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    Walking the Tree of Life in simple SQL
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    Antony and I are busy getting the Open Query GRAPH Engine code ready so you all can play with it, but we needed to test with a larger dataset to make sure all was fundamentally well with the system.

    We have some intersting suitable dataset sources, but the first we tried in ernest because it was easy to get in (thanks to Roland Bouman for both the idea and providing xslt stylesheets to transform the set), was the Tree of Life which is a hierarchy of 89052 entries showing how biological species on earth are related to eachother.

    GRAPH engine operates in a directed fashion, so I inserted the connections both ways resulting in 178102 entries. So, I inserted A->B as well as B->A for each connection. So we now have a real graph, not just a simple tree.

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    GRAPH engine – Mk.II
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    The GRAPH engine allows you to deal with hierarchies and graphs in a purely relational way. So, we can find all children of an item, path from an item to a root node, shortest path between two items, and so on, each with a simple basic query structure using standard SQL grammar.

    The engine is implemented as a MySQL/MariaDB 5.1 plugin (we’re working on a 5.0 backport for some clients) and thus runs with an unmodified server.

    Demo time! I’ll simplify/strip a little bit here for space reasons, but what’s here is plain cut/paste from a running server, no edits

    -- insert a few entries with connections (and multiple paths)
    insert into foo (origid, destid) values (1,2), (2,3), (2,4), (4,5), (3,6), (5,6);
    -- a regular table to join on to
    insert into people values (1,"pearce"),(2,"hunnicut"),(3,"potter"),
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    RAM flakier than expected
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    Ref: Google: Computer memory flakier than expected (CNET DeepTech, Stephen Shankland)

    Summary: According to tests at Google, it appears that today’s RAM modules have several thousand errors a year, which would be correctable if it weren’t for the fact that most of us aren’t using ECC RAM.

    Previous research, such as some data from a 300-computer cluster, showed that memory modules had correctable error rates of 200 to 5,000 failures per billion hours of operation. Google, though, found the rate much higher: 25,000 to 75,000 failures per billion hours.

    This is quite relevant for database servers because they write a lot rather than mainly read (desktop use). In the MySQL context, if a bit gets flipped in RAM, your data could get corrupted, or

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    New Open Query training days in Australia
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    The favourite Open Query course modules as well as reworked and brand new ones, with November/December 2009 dates for Brisbane, Sydney, Canberra and Melbourne listed below. You can register for days/modules individually, to suit your time, budget and current needs. Your trainers are Sean, Ray and Arjen (see OQ people).

    For the Canberra and Melbourne days which are DBA/HA, registrations for all of the modules in a series before 15 October will receive a copy of the “High Performance MySQL” book (normal bookstore price is AUD 105).

    Canberra

    • Thu 5 Nov: MySQL High Availability – Strategy and Tools
    • Fri 6 Nov: MySQL Cluster
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    Dogfood: making our systems more resilient
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    This is a “dogfood” type story (see below for explanation of the term)… Open Query has ideas on resilient architecture which it teaches (training) and recommends (consulting, support) to clients and the general public (blog, conferences, user group talks). Like many other businesses, when we first started we set up our infrastructure quickly and on the cheap, and it’s grown since. That’s how things grow naturally, and is as always a trade-off between keeping your business running and developing while also improving infrastructure (business processes and technical).

    Quite a few months ago we also started investing (mostly time) in the technical infrastructure, and slowly moving the various systems across to new servers and splitting things up along the way. Around the same time, the main webserver frequently became unresponsive. I’ll spare

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    Tool of the Day: rsnapshot
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    rsnapshot is a filesystem snapshot utility for making backups of local and remote systems, based on rsync. Rather than just doing a complete copy every time, it uses hardlinks to create incrementals (which are from a local perspective a full backup also). You can specify how long to keep old backups, and all the other usual jazz. You’d generally have it connect over ssh. You’ll want/need to run it on a filesystem that supports hardlinks, so that precludes NTFS.

    In the context of MySQL, you can’t just do a filesystem copy of your MySQL data/logs, that would be inconsistent and broken. (amazingly, I still see people insisting/arguing on this – but heck it’s your business/data to gamble with, right?)

    Anyway, if you do a local mysqldump also, or

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    Tool of the Day: Firefox Tab Kit extension
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    We often need many tabs open in a browser, and horizontal tabs become unmanageable. Tab Kit allows you to have them vertically on the left, with various additional configuration choices.

    I opted for the tree structure, so when I open a tab from another one it’ll show up as a child to the original. I can “lock” tabs so they cannot be closed by an accidental click or keypress. They get a “read” marker so if you open a few tabs and leave them till later you can still tell which ones you’ve actually already looked at. And there’s colour coding also.

    In short, a great help. Just click the Tools/Add-Ons menu in Firefox and find Tab Kit in the extensions. Install, configure, and enjoy!

    The Flipside of Uptime
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    We just had a booboo in one of our internal systems, causing it to not come up properly on reboot. The actual mishap occurred several weeks ago (simple case of human error) and was in itself a valid change so monitoring didn’t raise any concerns. So, as always, it’s interesting and useful to think about such events and see what we can learn.

    Years ago, but for some now still, one objective is to see long uptime for a server, sometimes years. It means the sysadmin is doing everything right, and thus some serious pride is attached to this number. As described only last week in Modern Uptime on the Standalone Sysadmin blog, security patches are a serious issue these days, and so (except if you’re using ksplice

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    BarCamp Melbourne 12-13 September 2009
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    Open Query is pleased to sponsor BarCamp Melbourne, a rocking unconference held at UrbanCamp, Royal Park, Melbourne VIC (Australia). If you’re anywhere nearby this coming weekend (12-13 September 2009), you really really want to be there and participate, learn, and enjoy! Open Query’s own Peter Lieverdink (cafuego) will be there.

    Barcamps are run at low cost, but of course there are still costs, so it’s very important that lots of businesses and people toss in something to help cover that. If you would like to contribute, just follow the links and Ben or Donna will be happy to help.

    Market share vs market impact
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    This is very relevant in the context of the EU probe of the Oracle-Sun takeover. MySQL’s share of the database market, which is usually measured by revenue, is of course peanuts and estimated range from half a percent to something slightly more. Peanuts.

    This is not surprising, considering an estimated 999 out of every 1000 MySQL users does not pay Sun/MySQL anything (although some might be Open Query clients and while MySQL has been targeting higher-end clients and corresponding higher revenue, its pricing is still far lower than the premium-cost of Oracle, DB2 and the like.

    All this proves very clearly something which I’ve been saying for years (do scan back in my blog , the definition of market share

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    Showing entries 1 to 30 of 53 Next 23 Older Entries

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