When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.
There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the
| # this is a dirty implementation of logger that | |
| # compiles AR queries with trace into /last_request_log.html | |
| # the snippet is useful when optimizing performance of the endpoint | |
| class QueryLogSubscriber < ActiveSupport::LogSubscriber | |
| TRACE_LEVEL = :app | |
| LINES = 5 | |
| IGNORE_CACHED_QUERIES = false | |
| def initialize |
| #!/bin/bash | |
| # Usage: slackpost <token> <channel> <message> | |
| # Enter the name of your slack host here - the thing that appears in your URL: | |
| # https://slackhost.slack.com/ | |
| slackhost=PUT_YOUR_HOST_HERE | |
| token=$1 |
Ideas are cheap. Make a prototype, sketch a CLI session, draw a wireframe. Discuss around concrete examples, not hand-waving abstractions. Don't say you did something, provide a URL that proves it.
Nothing is real until it's being used by a real user. This doesn't mean you make a prototype in the morning and blog about it in the evening. It means you find one person you believe your product will help and try to get them to use it.
| # Git pre-commit hook to check all staged Ruby (*.rb/haml/coffee) files | |
| # for Pry binding references | |
| # | |
| # Installation | |
| # | |
| # ln -s /path/to/pre-commit.sh /path/to/project/.git/hooks/pre-commit | |
| # | |
| # Based on | |
| # | |
| # http://codeinthehole.com/writing/tips-for-using-a-git-pre-commit-hook/ |
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
This set of scripts and config files will help you set up the awesome combination of Unicorn and Nginx as a server environment for Ruby web applications on Red Hat's OpenShift platform while I finish my cartridge.
| #!/bin/bash | |
| # from here: http://www.codingsteps.com/install-redis-2-6-on-amazon-ec2-linux-ami-or-centos/ | |
| # and here: https://raw.github.com/gist/257849/9f1e627e0b7dbe68882fa2b7bdb1b2b263522004/redis-server | |
| ############################################### | |
| # To use: | |
| # wget https://raw.github.com/gist/2776679/04ca3bbb9f085b192f6aca945120fe12d59f15f9/install-redis.sh | |
| # chmod 777 install-redis.sh | |
| # ./install-redis.sh | |
| ############################################### | |
| echo "*****************************************" |
| function countCSSRules() { | |
| var results = '', | |
| log = ''; | |
| if (!document.styleSheets) { | |
| return; | |
| } | |
| for (var i = 0; i < document.styleSheets.length; i++) { | |
| countSheet(document.styleSheets[i]); | |
| } | |
| function countSheet(sheet) { |
cribbed from http://pastebin.com/xgzeAmBn
Templates to remind you of the options and formatting for the different types of objects you might want to document using YARD.
