Third Day at OWF 2011

Last but not least day at OWF this year. Yep, this is a saturday, but this was the code time for me, so probably the most interesting no😉 ?

I started the day my making first 2 interviews for the WebTV of the event, one in french and another one in english explaining Open Source at HP. That’s what you get by sponsoring events😉 So now, my kids can compare me with every other product seen on the TV !! By the way, it allowed me to understand that the professional video world is still unable to use FLOSS only technologies to perform such activities, and if you have spare time, and no defined project to work on, that would be a great addition to our community.

Then it was time to attend the sessions of the day and take some notes to share with you.

Lua and its ecosystem by François Perrad.

Lua is developed in Brazil using a closed development approach (just tar balls), even if it is Open Source since 1993, under the MIT license (which François underlined as important for its adoption by the embedded applications).
It’s a scripting language, fast, powerful and lightweight.

v5.1.4 is the stable version (from 2008)
v5.2 is now ongoing
(Some people still use v4 for its C API and the apps developped with it)

The language is concise but powerful: EBNF Grammar of 1 page and a Reference manual of 100 Pages (with C API, and libs included). It is 12.5 kLOCs and the binary size is 150 kB.
There are only 8 types and 21 keywords.
Lua has a table type like a hash, which allows to make everything.
It also has a userdata type to manipulate C structs/objects e.g.

Lua is portable (written only in C89 – but C++ compatible)
It exists for Linux, OSX, Windows, Android, iOS and Lego (eLUa). Other implementations exist: LuaJIT, LLVM-Lua, MochaLua, Jill (Mobile)

Lua is small but powerful (such as perl, python, ruby, subject of this conf) – It supports regex
François then showed examples of factorial and fibonacci programs written with it.
It is very easy to embed with C programs.

Lua modules are heterogeneous (no CPAN), so build, doc, test and packages are multiple.
Lua has Modules such as sockets, POSIX, XML, DB, wxLua, GTK, JSON, Corba, …

François gave then some application examples: textadept (text editor, 2kLOC C + 6 kLOC Lua), Wireshark (added scripting support with Lua), awesome (Window Manager), redis (key/value tool, server side scripting with Lua)
Lua has too few sponsors: Adobe (Lightroom), SocialMediaPress, CSTUG, OCé.

François complained that there is not a lot of return to the community in term of code from these sponsors. But after all, my take on this is that this is certainly due to the choice of license (permissive) and of development model which doesn’t invite or force contributions to be brought back. One of the reason I chose the GPLv2 for my projects. Clearly it seems interesting if you need to add scripting support to a software. now, IMHO not done to develop applications directly.

Colin Charles (Monty Program AB)
Chief Evangelist on MariaDB (he left when Sun bought MySQL)

Charles gave 3 conferences during the day to paint n state of the Art of MySQL and its ecosysem.
He started by presenting the MySQL Diaspora

Charles started by some MySQL history.
The MysQL release policy is: alpha, beta and GA. 5.0 was released in 2005.
InnoDB was bought by Oracle in 2005, which created problems. The Falcon engine, which was targetted for 6.0, was the solution but it never saw the light.
5.1 was released in 2008. Lots of bugs were present due to an early release and lack of tests. 5.2 was canceled (It should have been open to community contribs)
5.4 was the next release in the roadmap in 2008.
In 2009, Sun was bought by Oracle. As a consequence 5.4 & 6.0 were canceled.
5.5 was realeased in 2010.
5.6 is available at labs.mysql.com (2011).

InnoDB + memcached in front of it, is the NoSQL approach taken (even if Oracle doesn’t believe in NoSQL, surprise, surprise !!)
Half of the downloads at mysql.com were for Windows. But most people on Linux, OSX, BSD use the packaged MySQL from their OS which thus reduces the number of downloads for these platforms and gives a wrong impression of the usage. Secondlife e.g. used MySQL out of Debian.
However, distributions tend to include only a small subset of MySQL features. There are only 5 engines compiled in Fedora/RHEL !

Charles underlined that the real uniqueness of MySQL is its ability to use multiple engines very easily (more on that in a dedicated conference below).
He detailed the commercial ecosystem around MySQL for add-ons (InfoBright, TokuDB, ScaleDB, Nitro, SolidDB, RitmarkFS) as well as HardWare vendors too (Kickfire, Virident, Schooner – going away with Oracle) as well as 3rd party engines (that Oracle doesn’t like either)

Charles then gave definition of terms: Fork == do not merge back (Drizzle e.g.) – Branch: rebase all the time (MariaDB, Percona e.g.). He then expained the different MySQL children.

  • Percona started from 5.0 (it took Google/Facebook code on top of MySQL). So Percona is MySQL with InnoDB enhancements (coming from FaceBook/Google) and minimal server changes. They have 1000+ customers in the USA. They provide more fine grained diagnostics. (Google uses MySQL/Percona for Adwords). It provides FlashCache which makes it a great offering for SSD support. They also provide the Percona Toolikit (lots of perl scripts, it is the former maatkit UDFs) to make admin life easier. Their business model is mainly around consulting, and some support.
  • Drizzle is based on MySQL 6.0 whiwh was never released. It took them 3 years to release the GA, just recently, aimed to be the RDBMs for OpenStack. However, due to the time it took, OpenSTack now uses SQL Alchemy which supports multiple RDBMs. Drizzle is Unix only – No Windows. Drizzle has a Micro-kernel architecture so everything is a plugin (including optimizer, query caches, …). Fully written in C++ now (no C anymore), it targets Cloud. It uses a lot of other FLOSS tools (including Google Protocol Buffer). Patches from MariaDB are difficult to integrate as it’s a fork.
  • MariaDB started from 5.1, and is now with 5.5/5.6 also including Percona patches and abandonned patches. MariaDB is Percona and more storage engines and lots of improvements (including µs precision, extended stats for slow query log, threads pool support (eBay), pluggable authentication, virtual columns, NoSQL, subqueries (finally in 5.3 !!), GUI for Windows).
  • Other branches are OurDelta (pet project – died), MepSQL (just Facebook patches, died), XAMPP (Windows)

For NOSQL in MySQL, use MariaDB ! Its HandlerSocket provides 700000 queries/s vs 400000 queries/s for standard MySQL. It also provides Dynamic Columns, memcached interface to InnoDB and NDB (only in the labs of MySQL, MariaDB is waiting for publication to include it – droped in 5.1, maybe back in 5.6/5.7)

MySQL cluster is an external product, which will probably be integrated in main tree with version 5.6/5.7.

From a support perspective, many companies can deliver it: Oracle (MySqL ent), Percona (MySQL, Percona, MariaDB, Drizzle), SkySQL (MySQL, MariaDB, Drizzle, distros), and many others.

Charles announced that pap.fr just issued a press release about their migration to MariaDB.

He then underlined the difficulty to work with Oracle: There is no public roadmap for MySQL. MySQL is now OpenCore: threads (connection) pool is closed source (original patches from eBay !) with only API for community dev. PAM (AD plugin) code came from MariaDB and is now also closed source. InnoDB Hot Backup however has always been closed source. But xtrabackup is FLOSS. InnoDB has never been Open Source, and they are rebasing from what is published monthly.
These problems comes from the contribution agreement that Oracle forces MySQL contributors to adopt to integrate patches upstream, which gives them the possibility to close the code instead of integrating it inside the public version. Oracle is once again making foes here.

From a performance perspective, XtraDB in 5.5 > InnoDB in 5.5 > XtraDB 5.1.
Connectors remains 100% the same whatever the backend.

Scaling is the issue. Hopefully, working with HP on this we can help Monty programs make progresses on this side.
To a question I asked around Monty Programs, Charles explained that Monty Program is only developing around MySQL. Their business model is to sell 3rd level support and dedicated consulting around development. They have no interface with ordinary customers.

The ecosystem is now in fact split between multiple actors, compared to when MySQL AB was doing everything: Monty Program as the “Lab”, SkySQL for the support and Percona for the consulting, even if the last two overlap a bit.

I was lucky to lunch with Charles, so we could discuss into more details around the community, and some of the points upper were not presented during the formal presentation but are the result of my understanding during our talk. All mistakes are of course mine😉

During the next session, I had a discussion with Charles Schulz, administrator of the LibreOffice.org foundation to get some news of this community, and they have lots of plans, some announces that will happen in October, but that I can’t reveal for now. Stay tuned however as it’ll be great !!

Then I attended the second session from Charles Colin around Storage Engines of MySQL/MariaDB

The main engines are: MyISAM, InnoDB, NDB (aka Cluster), Falcon (dead), Archive, Federated(X), Merge, Memory, and the one from Partners, Community, Customers…
The Engines list also includes AWS, OpenLDAP, CSV, Blackhole, Q4M (queuing mecanism), …

Charles then explained the default choices:
MySQL 5.5 => InnoDB by default, MyISAM for temp files
MariaDB 5.5 => XtraDB by default, Aria for temp files (more secure, as crash safe)
Percona 5.5 => XtraDB by default, MyISAM for temp files
Drizzle => HailDB (the only engine), MyISAM for temp files

The value proposition of MySQL/MariaDB around the various engines is unique. It brings flexibilty very easily, from ACID compliant InnoDB, to memory engine for performance, to archive which compresses data up to 80%
There are of course differences between engines with regards to storage (side note advise; use XFS), indexes, memory usage, transactions support (ACID), …
To see what engines are supported in your version, use show engines (12 present in MySQL, 10 in MariaDB)
Engines are plugins handled as loadable modules after 5.1.
There are some commercial engines: InfoBright (Data warehouse), TokuDB (cloud)
To use a specific engine with a table use: create/alter table … engine=XtraDB
Distributions tend to remove engines in their delivery (half only in Fedora/RHEL).

Indexes use all type of algorithms available: B+trees (InnoDB), Red-black trees (memory), R-trees (MyISAM) + hash indexes (memory, NDB, InnoDB).
For MySQL benchmarks, Charles recommended to use mysqlslap, to which I’d also tend to add the excellent HammerOra, which will allow you to make comparison with other RDBMs very easily !

Charles then explained the specifics of some engines:

  • MyISAM: excellent insert perf, small footprint, full text support. No transactions, no foreign key. Usage: log, audit, Datawarehouse. Was preferred earlier. Not usable with DRBD. Tuning hint: Use key_cache_segments = 1 in MariaDB.
  • InnoDB: for OLTP, raw disk support (useful for Windows). Tuning is also required. Use innodb_file_per_table good when locking, innodb_buffer_pool_size to memory*0.8 if dedicated. show engine innodb status gives more stats on MariaDB. InnoDB supports row & statement replication. Hint: Use a primary key (if not, it will be done for you)
  • Archive: good for auditing (can’t delete in it, only SELECT and INSERT), uses libz
  • Federated was disabled in MySQL but FederatedX has replaced it in MariaDB.
  • FederatedX: Used by Cisco to store centrally from routers. Good for synchronous replication.
  • Memory: loosing popularity in favour of memcache (BTW there is also a memcache engine !) Used for lookup, session, temp or calculation tables. Of course, when server goes down, rows are lost.
  • Aria: MariaDB only. Planned to be competing with InnoDB and was concurrent to Falcon (now dead). Crash safe MyISAM, may become ACID.
  • PBXT: ACID. Transactional. Good for SSD storage. Popular in Germany. Supports efficient BLOB. Should be more known.

To install a new engine just issue: INSTALL PLUGIN myengine SONAME ‘engine.so’

Charles reminded that a mix and match of engines is frequent.
He underlined that backup is engine dependant. LVM snapshots are a way to solve this.
Monitoring is also engine dependant.
Wordpress uses MyISAm, Wikipedia/mediawiki prefers InnoDB except search, SugarCRM uses MySQL.

Was time for me to take the mic ! and talk about
Continuous packaging with Project-Builder.org by Bruno Cornec (HP)

Brilliant presentation as usual😉 Find it online and hopefully at OSDC.fr where the Vidéo should appear soon.

Open Build Service by Vincent Untz (SuSE)

I stayed in the room to listen to Vincent, who insisted on the new name of the former OpenSuSE Build system which is now the Open Build Service (Vincent, I’ve now patched my presentation to be aligned ;-))

Even if goals are similar (building more easily packages and supporting a continuous packaging approach, there are still some differences I think between the tools. First, of course, language used to develop them (perl for Project-builder.org and Ruby on Rails for obs), but also on pb side the willingness to share metadata across packages, in a VCS and providing a macro system to support it, the support of VMs *and* Virtual Environment* and now *Remote Machines*, with tools such as rpmbootstrap to help users managing them, the standalone aspect of the tool and it’s ease of deployment (just 3 perl packages + 2/3 deps max – fewer LOC). Also pb supports gentoo, and Solaris, and is very easy to extend as everything is now managed through configuration files.

Advantages on obs side are its great Web based interface, its reporting mecanisms, and its capability to rebuild projects based on modifications of other projects. obs announces a very large user base, and packages built, even if when you divide by the number of distro tuples it’s less of course. pb just supports 5 different projects so has a much less reduced installed base.

Vincent did a very good presentation, as usual, showing also how it had a positive impact on the OpenSuSE project by having all the build infrastructure rebuilt to be Open Source (GPL) in order to support the project. Another big plus of their infrastructure is their BaaS approach (Build system as a Service), whereas with pb you need to create it, even if it’s easy. However, Vincent underlined that OBS as BaaS is only accessible for Open SOurce projects. If you’re building other software types, then we are at parity as you need to deploy the tool in-house.

As I underlined at the end of my talk before welcoming Vincent, whatever the tool you use, what is the most important, is to promote continuous packaging, as a good practice of today for projects (Open Source or not). Everybody’s new mantra should become “package early, package always” !

Charles then made his last presentation of the day (busy guy !) on MariaDB.

He reminded that it is a branch of MySQL, community developped, feature enhanced and backward compatible.
Monty Program is the main sponsor of MariaDB (58% of patches come from Monty Program, 42% from commmunity members having commit access)

MySQL is now an Open Source/Core product not a project.
MariaDB is an Open Source project, with the goal to be 100% compatible and a drop-in replacement of MySQL.
It is stable (production ready) and GPLv2. XtraDB (vs InnoDB) is enabled by default.
Charles then covered the various versions published:

  • 5.1: Spend lot of time on build system (Buildbot + VMs😉 for 5.1. No compiler warnings (contributed back). Table Elimination (aligned with big RDBMs) improves perf. Pool of threads (or connection pool, good for short running queries).
  • 5.2: Pluggable authentication. Easy to write in 1/2 days AD auth/PAM auth as Oracle published recently. Virtual columns. Includes ShpinxSE (Full Text Search Engine)
  • 5.3: NoSQL (HandlerSocket – direct access to InnoDB in perl DeNA, Dynamic columns, Group Commit, Replication, mytop, optimizer, optimized subqueries). That code may not be given back to Oracle due to Oracle recent announcement.

Everything done in the open, ML, bugs, IRC, code, worklog, KB (1400 articles in 1 year, cc-by-sa) …

Future: GIS. Merging takes more and more time. Future may be to fork to solve the Open COre MySQL approach, which would be IMHO good news for the FLOSS world, as it was sith LibreOffice e.g.

Blocks in perl6 by Christian Aperghis-Tramoni

A real course on how perl6 manages some blocks (functions where particularly detailed). Not a lot of notes, here as everything is online, and this was mostly code explanations, so I prefered to follow, rather than taking useless notes that nobody would read anyway ! What I mostly retained is that perl 6 brings some huge differences with regards to perl 5, certainly in the good direction, but will need an adaptation from old perlers such as myself, not following closely perl 6 development as Christian, and also that it’s not yet ready for usage, as lots of features are not there yet, and no optimisation is available, so from a production perspective, it’s unusable now. Perl 5 has for sure a very long life in front of him🙂

All in all, OWF 2011 was again a great event. However, I would prefer for next year that they concentrate mostly on the Think part, which is quite unique to this conference and makes all its value, whereas code and experiment are already well represented at RMLL or Fosdem. See you there next year hopefully !

Note: Some of my photos related to this event are now available at https://picasaweb.google.com/112434061686721373729/OWF2011

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