55 lines
2.5 KiB
Markdown
55 lines
2.5 KiB
Markdown
permalink: "/{{ year }}/{{ month }}/{{ day }}/redis-faq-or-what-you-learn-when-idling-in-redis"
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title: "Redis FAQ or: what you learn when idling in #redis"
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published_date: "2013-11-10 21:10:00 +0100"
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layout: post.liquid
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data:
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route: blog
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---
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Sometime ago I created the [redis-faq][], a small list of common or not so
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common questions coming up in the `#redis` channel on freenode.
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There's not much on it yet, but I would like to extend it whenever possible.
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If you have something you want to add just ping me on [twitter][] or on freenode (`badboy_`).
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For now these are the only things in there so far:
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### Q: X is weird in my instance. Can you help?
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Maybe. To better help please give the following info:
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* Output of `redis-cli INFO`
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* Output of `redis-cli CONFIG GET '*'`
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Don't spam the channel, upload it to [pastebin][], as a [gist][] or similar.
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### Q: I want to use [SELECT](http://redis.io/commands/select) to seperate my data. Is this a good idea?
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Antirez decided `select` was an anti-pattern a loooong time ago. He won't fully
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deprecate it, but it doesn't get support in new features such as cluster. (via
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[brycebaril][]).
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[Relevant mail][ml-select].
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Just use seperate instances or use namespacing (often used: `namespace:real-key-name`)
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### Q: I have some data and need to retrieve it by date. How to to that?
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[Sorted Sets](http://redis.io/commands#sorted_set) can be useful here.
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Store some value and use the timestamp as the score. Then use [ZRANGEBYSCORE](http://redis.io/commands/zrangebyscore) to get it back.
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### Q: I installed a new version, but `redis-cli info server` still shows the old one
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* Make sure the old instance is already stopped. `pidof redis-server` or `ps aux | grep [r]edis-server` should only list one PID.
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* Make sure you're starting redis from the right path (if installed manually it might be different than when installed from your package manager)
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* Make sure you're connecting to the right port. It is possible to run multiple instances on different ports (default port is 6379)
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### Q: I have a background in SQL. Now I'm looking into how I can use Redis. Anything I need to consider?
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If you're used to SQL, storing data in Redis is more like creating the indexes for your SQL schema (from: [brycebaril][])
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[redis-faq]: https://gist.github.com/badboy/5958039
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[twitter]: https://twitter.com/badboy_
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[brycebaril]: https://github.com/brycebaril
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[ml-select]: https://groups.google.com/forum/#!msg/redis-db/vS5wX8X4Cjg/8ounBXitG4sJ
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[pastebin]: http://pastebin.com/
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[gist]: https://gist.github.com/
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