Xarg blog Archive

An article on tuning queries by munging through the postgres server logs.

veryone wants their database-backed web application to run faster on the same hardware - if a software tweak can postpone a hardware upgrade for a year, it's usually well worth it. One way to improve performance is to examine how the application is interacting with the database, and see if there is anything that we can do to speed things up. We will take a look at a handy script that can examine PostgreSQL logs and let you know what queries are getting run the most.

I wanted to try to figure out why AOLServer gets so large when generating pages with a lot of data (when the CVS browser generates a large page the AOLServer binary can grow by 100MB or so -- not a great thing to have happen). Anyway, I fired up GDB and was trying to figure out what was going on and had no success at all. I could not even set a breakpoint...

It turns out that on gentoo (and some others, like Mandrake 9), libpthread is stripped which means GDB can't do anything useful when debugging threaded programs.

If you see

/lib/libpthread-0.10.so: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), stripped

or get the error

Program received signal SIG32, Real-time event 32.
0x40163834 in pthread_getconcurrency () from /lib/libpthread.so.0

when trying to debug a threaded program, then you will need to get an unstripped version of libpthread, or rebuild it on gentoo with

FEATURES="nostrip" emerge glibc

Interesting articles on open source in the ACM Queue magazine....

In our first open source theme issue last year (ACM Queue 1(5), July-August 2003), we focused on business issues such as using open source software as a basis for a commercial product. We knew that this was an important topic, but predicted that many of our readers might find it boring. We were wrong. That issue remains among the most responded-to issues of Queue to date. So with that response, we are revisiting the open source theme.

After several years of running KDE I realized I don't actually use anything from KDE (besides konsole) and decided it was time to try some other window managers. I am using windowmaker now and I like it so far. I like workspaces and I like the dock but I can't figure out how to get click to raise working without doing alt-right click in the active window (I liked the kde behavior of simply clicking on the window to raise it).

I had to unbind a bunch of things that conflicted with my emacs key bindings.

I have not figured out how to get it to save my descktop but given that I logout once every couple months I may not bother.

I upgraded to OpenACS 5.1 and moved the server off of our overloaded shared machine (although it's still somewhere in Texas). Upgrading was not as bad as I thought it might be although there are a bunch of little things still broken.

I changed my dns entry as well so that may take a day or two to propigate (which hopefully won't bork my email as well, since before I did not have an MX record for xarg.net).

I am always entertained when I find the consequence of spell checking without corresponding proofreading in books or in the newspaper. Today's online version of a Times Op-Ed piece was a pretty funny example:

For some years now, the Energy Department has been hoping to separate its wastes into two streams, reserving deep burial for only the part with high radioactivity. In the case of the South Carolina site, the department is prepared to pump most of the waste out of the tanks for disposal through deep burial. But it wants to leave a hard-to-remove residue of sludge in the tanks and bury it under grout.

Maybe it's just me but I find it hard to imagine that grout is the ideal encasement material for high level nuclear waste...

I just got two 20" LCD monitors (eizo l885's) to replace my 19" CRTs. I thought they would be better but I am utterly astounded by how much better they are. Although I think switching to DVI made a big difference too. In any case, if you are thinking of spending 4x as much as your computer cost on monitors, I recommend the eizo LCDs. One nice touch is you can turn off the annoyingly bright blue power led from the on screen menu.

One curiosity is that the monitor controls are black buttons with black writing on a black bezel. Sort of reminds me of that spaceship in Hitchhicker's Guide to the Galaxy.

I have been blogging my notes for KM and Community of Practice at sm.xarg.net...

I saw a mention of a really nice article by David Wheeler titled Comments on Software Configuration Management (SCM) Systems. We have talked about switching to something better than CVS for OpenACS development but I don't think collectively we have the will to do it yet. I played with arch some and I certainly found it difficult to get used to the naming conventions it requires and the fiddly nature of setting up an archive but I agree with David Wheelers conclusion:

Personally, although I'd be happy to use subversion on others' projects, I personally plan to use GNU Arch; its warts are numerous, but I think they'll be rapidly fixed and GNU Arch has a tremendous amount of promise.

There is a beautiful presentation on “visualizing dynamic, evolving documents and the interactions of multiple collaborating authors” from the Collaborative User Experience Research group at IBM (via Object Learning). I think the diagrams have a particular Tufteian beauty.

I would love to have a tool like this for the OpenACS source. Sort of like colored diff in cvsweb but extended over all versions. Of course in CVS you have the added complication of branching an merging but even so it would be cool. I love things that expose the history of documents and foster that sense of shared ownership and collaboration and it's hard to imagine something more effective than this tool.

I found the article about the Win2K source at Kuro5hin.org pretty entertaining. The funny thing is the whole issue of innappropriate comments in code has come up a number of times with ACS and later OpenACS. It even inspired Philip to write an article about it and it came up more than once from clients who looked at the source. I am not at all surprised to find that comments like this exist in Microsoft's code since they are not at all visible to the end user, well not usually anyway :)

There are still a lot of "Hack" type comments in OpenACS but since the code is visible and people have complained, we have thought of the children and removed the "f word". I really like the pithy comments though, it does a far better job of conveying the history of the code and the personalities of the people who have worked on it that a grey uniform "professional" expunging of anything even remotely offensive ever could.

Code needs to work and be correct but the comments should convey the intent and the nuance of complicated ideas. And with large messy systems sometimes nuance is just not enough...

I finally made it to Shine Gallery to pick out my christmas present. A picture of a bug! But not just any picture, these are amazingly detailed photos constructed from a mosiac of hundreds of scans from an electron microscope. They capture the essence of bugness and are astonishingly detailed. The artist who makes them is Giles Revell and there are a couple nice articles at scicult and The Manchester Museum about his work.

I have always been fascinated by electron microscopy ever since I saw a real electron microscope at the exploratorium in San Francisco when I was a kid and it always seemed strange to me that you could not get more images like this. Going to Shine gallery, they showed me the works in progress and artists proofs and I now realize why there are not more images like this around. It's an incredible amount of work to create one. One thing they have is all the individual scans on one page as thumbnails and when you realize each one takes a while to do properly and the stitching of the images is time consuming and there really are hundreds in each image, it's amazing that Mr. Revell has had the patience and vision to create these.

I am excited to get my prints and I think it's about the best Christmas present I have ever gotten. The most amazing thing about all this (besides the prints themselves) is that Shine Gallery is about a block from my house. My only regret is that I don't have space for the large images which are typically a meter or two across, although maybe I could put one over the dining room table :)