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Displaying posts with tag: PBXT (reset)
PBMS version 0.5.09 has been released.

A new release of the PrimeBase Media Streaming engine is now available for download at .

The main focus of this release was to provide the features required to make PBMS production ready and with the addition of transaction support and engine level backup I think it is almost there. The engine does not yet provide engine level replication but it will in a future release.

What's new:

  • PBMS now provides two methods to backup the BLOB repository which are documented here.
  • PBMS now supports transactions independently of the storage engine.
  • There is now a PHP extension for PBMS. Check it out!
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Jeremy's article on PBXT in Linux Magazine

Jeremy Zawodny of Craigslist wrote a great article on PBXT for Linux Magazine:

PBXT: Your Next MySQL Storage Engine?

Check it out...

Thanks Jeremy :)

PBMS is transactional!

The PBMS engine now has built in support for transaction so that if you reference or dereference BLOBs during a transaction the changes you made will be committed or rolled back with the transaction. Up until now PBMS had depended on the host engine to handle transactions and inform it what needed to be done in the event of a rollback.

I have implemented transaction support by adding a circular transaction log and transaction cache. The circular transaction log is dynamic and can grow and shrink as required. The transaction records are all small (30 byte) fixed length records so the log doesn’t need to be that large to be able to handle a lot of transactions. A head and tail pointer are maintained to indicate where the head and tail of the circular log is. If the circular log becomes full then the records just overflow and are written to the end of the log. Once the transaction reader has caught up after an overflow has occurred it …

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PBXT 1.0.08 RC2 Released!

The second Release Candidate of PBXT, version 1.0.08, has just been released.

As I have mentioned in my previous blogs (here and here), I did a lot to improve performance for this version.

At the same time I am confident that this release is stable as we now have a large number of tests, including functionality, concurrency and crash recovery. But even more important, the number of users of PBXT has increased significantly since the last RC release, and that is the best test for an engine.

So there has never been a better time to try out PBXT! :)

You can download the source code, and selected binaries from here: …

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At last we have a MySQL Foundation, its called The Open Database Alliance

Just over a year ago we registered the domain name in the hopes that Sun/MySQL will actually create such an entity.

My idea was to move the development of the MySQL Community server to the Foundation and make the development fully community orientated. The Foundation would have its own development goals and release schedule. Sun could then pull patches from the Foundation's Community server into the Enterprise server once they had stabilized.

I pitched the idea to several people at Sun back then and over the last year, however, for some reason, the foundation concept just proved impossible to push through.

I believe this would have been a great opportunity for Sun to take the leadership in the community, as the foundation idea dates back to before things really started …

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Hindsight on a scalable replacement for InnoDB

A while ago I posted about a comment a Sun performance engineer made about a scalable replacement for InnoDB. At the time, I did not believe it referred to Falcon. In hindsight, it seems even clearer that the Sun performance experts were already working hard on InnoDB itself.

Sun’s engineers have shown that they can produce great results when they really take the problems seriously. And I’m sure that InnoDB’s performance has untapped potential we don’t see right now. However, it does not follow that their work on InnoDB is what was meant by a scalable replacement for InnoDB. Or does it?

General-purpose MVCC transactional storage engines with row-level locking, whatever their performance and scaling characteristics in …

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Selectivity threshold for a non-covering index

Assume you have a table with about 300 000 rows, and an indexed column ‘col1′ with only 9 distinct values. Now you got a query like ’select * from t1 where col1 = const’. The questions are

- when the index is faster to full table scan and vice versa?
- does MySQL use the optimal plan by default?

These questions became very relevant now that QOT got server access and is able to gather various table metrics including selectivity. Besides index selectivity the threshold value obviously depends on the storage engine used, so for me it is also interesting to see how our PBXT engine compares to others in this aspect. Namely to InnoDB - an engine with similar transactional properties and MyISAM - a very fast engine for read-only scenarios.

For the test I took the …

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PrimeBase Engines at the MySQL Conference 2009

Barry, Vladimir and I (the entire PrimeBase dev team!) will be presenting next week at the MySQL User Conference and Expo.

We've got lots of cool stuff going on. Barry will tell you how PBMS can store your BLOBs in the clouds, Vladimir will be explaining what makes PBXT so fast, and I will be talking about the past, the present and the future...

Even if that all doesn't interest you, be sure to just drop by to say hi. We're friendly, really! :)

The PBXT Storage Engine: Meeting Future Challenges
Paul McCullagh
3:05pm - 3:50pm Tuesday, 04/21/2009
Ballroom B

BLOB Streaming: Efficient Reliable BLOB …

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BLOB storage in the cloud with PBMS

I am pleased to announce a cloud storage version of the PBMS engine.

What I have created is a version of PBMS that stores the BLOB data in a cloud and when a request for the data comes in the client is sent a redirect to get the BLOB directly from the cloud. The BLOB reference tracking and metadata is handled the same as before in that they are stored in the BLOB record in the repository but the actual BLOB is stored somewhere else.

This has several advantages over storing the BLOB in the repository record:

  1. It reduces the disk storage requirement of the database server’s machine.
  2. It reduces the bandwidth requirement of the database server’s machine.

The beauty of it is that the client application doesn’t need to know anything about the cloud …

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The PrimeBase BLOB Streaming (PBMS) engine alpha version 5.08 is ready

Alpha version 5.08 of the BLOB streaming engine for MySQL has been released. You can download the source code from The documentation has also been updated.

What's new in 5.08:

  • All PBMS data is stored under a 'pbms' directory in the MySQL server's data directory rather than in the database directories them selves.
  • This version now builds with Drizzle and can be loaded as a 'Blobcontainer' plug-in.
  • Added the possibility of storing BLOB metadata along with the BLOB in the repository.
  • Added the possibility of assigning an alias to a BLOB, which can then be used to retrieve the BLOB instead of using the engine generated URL.
  • Added an updateable system table 'pbms_metadata_header' to control which HTTP headers are stored as metadata.
  • Added an updateable …
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