Glitch-Shrike/db
unarist 0129f5eada Optimize FixReblogsInFeeds migration (#5538)
We have changed how we store reblogs in the redis for bigint IDs. This process is done by 1) scan all entries in users feed, and 2) re-store reblogs by 3 write commands.

However, this operation is really slow for large instances. e.g. 1hrs on friends.nico (w/ 50k users). So I have tried below tweaks.

* It checked non-reblogs by `entry[0] == entry[1]`, but this condition won't work because `entry[0]` is String while `entry[1]` is Float. Changing `entry[0].to_i == entry[1]` seems work.
  -> about 4-20x faster (feed with less reblogs will be faster)
* Write operations can be batched by pipeline
  -> about 6x faster
* Wrap operation by Lua script and execute by EVALSHA command. This really reduces packets between Ruby and Redis.
  -> about 3x faster

I've taken Lua script way, though doing other optimizations may be enough.
2017-10-27 16:10:22 +02:00
..
migrate Optimize FixReblogsInFeeds migration (#5538) 2017-10-27 16:10:22 +02:00
schema.rb foreign_key, non-nullable, dependent: destroy in account_moderation_notes (#5294) 2017-10-10 13:12:17 +02:00
seeds.rb Fix db:seed - only run some validations when the field was changed (#3592) 2017-06-08 09:22:01 -04:00