6th October 2011
For some reason, I believed that MyISAM storage engine should be very fast - faster than InnoDB and Postgres. After all, MyISAM does not support transactions, has no logging, and is overall simpler than "true" storage engines/databases.
I was surprised to find out that this isn't true, at least for the specific (simple!) query I'm interested in:
SQL:SELECT primary_id FROM tablename WHERE indexed_varchar = %s AND intcol1 <= %d AND intcol2> %d
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Posted in Notepad | No Comments »
15th August 2011
Sometimes there is a need to be sure that no identifier is processed twice - for example, when parsing a file into a database, with file potentially containing duplicate records. An obvious solution is to properly wrap the DB insertion code into try...except block, and process duplicate primary ID exceptions. Another, sometimes more desired solution is to maintain a set/list of processed IDs internally, and check against that list prior to attempting the insertion of anything. So is it a set or a list?
There are already quite a few internet resources discussing "python set vs list", but probably the simplest while elegant way to test that is below.
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Posted in Notepad, Programming, Python | 1 Comment »
14th August 2011
Posted in Links, Notepad, Software | No Comments »
13th August 2011
Inspired by video encoding with handbrake.
HandBrake is a very high-quality piece of software - next time you need recoding something into H.264/MPEG-4 (using MKV or MP4 containers) - try HandBrake. It easily saturated all my CPU cores - which I failed to achieve with ffmpeg, which even with threads=8 was only saturating 2 cores.
Attached to this post are 2 profiles for recoding movies for Nokia E71. The "_best" profile has exhaustive motion detection, otherwise is identical to the base profile.
E71.plist
E71_best.plist
Related:
Posted in Links, Misc, Movies, Notepad | No Comments »
10th April 2011
Amarok moodbar wiki page has 2 nice scripts to generate .mood files for your whole music collection (to be displayed by amarok when playing).
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Posted in *nix, Links, Notepad, Software | No Comments »
28th March 2011
Under a few assumptions (most importantly - you do not have any non-merged branches,), it is very easy to throw away git repository commits older than an arbitrarily-chosen commit.
Here's a sample script (call it e.g. git-truncate and put into your ~/bin or whichever location you have in PATH).
CODE:#!/bin/bash
git checkout --orphan temp $1
git commit -m "Truncated history"
git rebase --onto temp $1 master
git branch -D temp
Invocation: cd to your repository, then git-truncate refspec, where refspec is either a commit's SHA1 hash-id, or a tag.
Expected result: a git repository starting with "Truncated history" initial commit, and continuing to the tip of the branch you were on when calling the script.
If you truncate repositories often, then consider adding an optional 2nd argument (truncate-commit message) and also some safeguards against improper use - currently, even if refspec is wrong, the script will not abort after a failed checkout.
Thanks for posting any improvements you may have.
Source: Tekkub's post on github discussions.
See also: how to remove a single file from all of git's commits.
Posted in how-to, Notepad | No Comments »
16th February 2011
Imagine you need to install pycassa (which uses easy_install). Here are the 2 (at maximum) very simple steps to have it properly debianized and installed on your Debian/Ubuntu:
- if you don't have the python-stdeb package: sudo aptitude install python-stdeb
- pypi-install pycassa
That's it.
Refer to stdeb readme for more information. You will need that if there are dependencies - which might not be resolved automatically by stdeb.
Before stdeb, it wasn't exactly trivial to make a .deb from python module.
Posted in *nix, how-to, Notepad, Python, Software | 1 Comment »
