MySQL query optimizing

July 11, 2008

A not so complex query was taking a huge time to complete (hours …).

I searched for an “EXPLAIN ANALYSE” a la PostgreSQL on MySQL … this does not exists.

BUT

They have a less featured command called “EXPLAIN EXTENDED”[1][2] that outputs some interesting information.

I found that adding two indexes helped me to have the query processed in some seconds … ūüėČ

[1] The EXTENDED argument did not change the ouput I had …

[2] Using explain from mysql website


Eclipseme frustrations

July 9, 2008

Developping an application for a TC65 I am using Eclipse (3.1.2) with EclipseME 1.2.3.

Some annoying things :

– When calling J2ME -> Create Package, if some dependencies aren’t met, the project is not build (a logic behaviour) but no error messages are provided. Thus, when not correctly waked up, you end up with some changes in the code not replicated in the deployed jad/jar …I guess that updating to the latest EclipseME version would probably improve this.

– Obfuscation crashes whith the following error message : “Cannot run program “env”: CreateProcess error=2″ …

– Debugging from Eclipse does not work on Vista … It seems that the dial-up connection that must be started to discuss with the TC65 does not work on my Vista installation. This works fine on a XP installation. This is not an EclipseME problem but an SMTK one …


Sniffing RS232 traffic with python

July 4, 2008

Today, I had to check that traffic between an embedded java application (in an eWON 4101) and a Coronis WavePort modem was following a given rule (less than 10 milliseconds between the bytes).

I have used a great thing : the SpyCable. It allowed me to monitor either the send traffic or the received one using two serial ports. I’ve then written a small python script to monitor the bytes entering the port,¬† printing Coronis frames with time information if some bytes were written with more than 10 milliseconds interval.
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Back to latex

July 3, 2008

Having to write two papers to finish my master, I went back to latex this morning. Vim is still my friend ūüėČ

Installing vim-latexsuite, makes me discover the vim-addons command used to enable/disable/… addons for vim :
ddp:/home/did$ vim-addons
# Name                     User Status  System Status
editexisting                removed       removed
justify                     removed       removed
latex-suite                 removed       removed
matchit                     removed       removed
ddp:/home/did$ vim-addons install latex-suite
Info: installing removed addon 'latex-suite'
Info: Rebuilding tags since documentation has been modified ...
Processing /home/did/.vim/doc/
Info: done.

vim-latexsuite is really nice. See http://vim-latex.sourceforge.net for more information. The problems with accentuated characters can be solved easily (vim-latex FAQ)

I manage my bibliography entries using JabRef.


AT+CNMA not working with TC65

July 2, 2008

Trying to have the new sms and status reports forwarded to the terminal using a TC65, it seems that AT+CNMA command is processed but not  working.

In my java application, I enable the following parameters.

AT+CSMS=1

AT+CNMI=3,2,0,1

Then on each +CMT or +CSD, I entered a AT+CNMA=0 (because i’m in PDU mode). Answer is OK but after that, the TC65 keeps sending me the first received SMS on every entering message (status report or sms).

Finally, I had to use the AT+CNMI=2,1,0,2 and parse message from memory in place of forwarding them directly to the tc65

PS: i’m using the latest smtk (revision 3.0)