pdx.rb Redis presentation notes

redis-memory-debugging-notes.txt

# Redis memory dump tool
https://github.com/sripathikrishnan/redis-rdb-tools

# Generate dump csv 
rdb -c memory dump.rdb  >dump.csv

# Filter out unique IDs from Redis key names
time cat dump.csv | ruby -pe '$_.gsub! /:\d+:/, ":"' >keys.csv

# ... or in Perl
time cat dump.csv | perl -pe 's/:\d+:/:/g' >keys.csv

# CSVKit
http://csvkit.readthedocs.org/en/latest/

# Import CSV file into a sqlite database using csvkit
csvsql -i sqlite keys.csv | sqlite3 keys.db
sqlite3 keys.db
.schema
.mode csv
.import ./keys.csv keys

# Analyze in sqlite
SELECT key,ROUND(AVG(num_elements)),SUM(size_in_bytes)/1024/1024 FROM keys GROUP BY key;

# Write a script to truncate
bundle exec rails console
User.find_each do |user|
  zset = "recommendable:users:#{user.id}:recommended_wiggles"
  Recommendable.redis.zremrangebyrank(zset, 0, -101)
end