To follow up on this post: redis store 128 bit number
How to do a lexicographical search with an ipv6 address.
If I use it like this:
ZADD index 0 8000::/24
ZADD index 0 2001:db8:1f89::/48
ZADD index 0 2001:db9:1f89::/48
ZADD index 0 1234:5678:abcd:effa:4200:1972::/112
ZRANGEBYLEX index [2001:0db8:0000:85a3:0000:0000:ac1f + LIMIT 0 1
1) "2001:db8:1f89::/48"
But:
ZRANGEBYLEX index [2001:1db8:0000:85a3:0000:0000:ac1f + LIMIT 0 1
1) "2001:db8:1f89::/48"
An idea ?
Convert CIDR to IP range and add to ZSET start IP. Before adding IP fill its numbers by zero!
Example:
2001:db8:cafe:1:0:0:0:100 -> 2001:0db8:cafe:0001:0000:0000:0000:0100.
And use "ZREVRANGEBYLEX key [2001:0db8:cafe:0001:0000:0000:0000:0200 - LIMIT 0 1" to get start IP of a range.
Related
I have a redis hash store that looks like Item:<id>, with attribute name. I want to filter the hash store by a prefix for name attribute.
What I'm trying to do is store the name (lowercased) in a separate Z-set called Item:::name while setting the score to 0. By doing this, I'm successfully able to get the desired result using ZRANGEBYLEX however I'm unable to map the results back to the original Items. How should I go about implementing something like this?
I've seen multiple autocomplete examples for Redis which require the same functionality but without linking the words back to an actual Item (hash in this case)
In sorted sets the member can't be duplicated, it has to be unique. So different users with the same name will cause problem.
My suggestion requires application layer coding to parse response array and executing hash commands (it will be like secondary indexes);
127.0.0.1:6379> HSET user:1 name jack
(integer) 1
127.0.0.1:6379> HSET user:2 name john
(integer) 1
127.0.0.1:6379> HSET user:3 name keanu
(integer) 1
127.0.0.1:6379> HSET user:4 name jack
(integer) 1
127.0.0.1:6379> ZADD item:names 0 jack::user:1 0 john::user:2 0 keanu::user:3 0 jack::user:4
(integer) 4
127.0.0.1:6379> ZRANGE item:names 0 -1 WITHSCORES
1) "jack::user:1"
2) "0"
3) "jack::user:4"
4) "0"
5) "john::user:2"
6) "0"
7) "keanu::user:3"
8) "0"
127.0.0.1:6379> ZRANGEBYLEX item:names [jack [jo
1) "jack::user:1"
2) "jack::user:4"
At the end you will have name::hash-key formatted array elements. At application layer if you separate each element to two substrings by using ::(any other string such as !!! or || etc) you will have user:1 and user:4.
127.0.0.1:6379> HGETALL user:1
1) "name"
2) "jack"
127.0.0.1:6379> HGETALL user:4
1) "name"
2) "jack"
127.0.0.1:6379>
I have an index for each user which represents their current score.
I want to find all users with the same score.
Provided that the input is as follows, how can I retrieve only users 1 and 2?
ZADD users 0 1:10
ZADD users 0 2:10
ZADD users 0 3:5
I would expect to do something like mentioned in the docs but I cannot use the key as my index since it is too large (for the post I changed to 1,2,3 so it is not an issue), which is why I set it to 0.
I thought the command could be something like ZRANGEBYLEX users [0:10 (:10 but that returns all 3.
1) "1:10"
2) "2:10"
3) "3:5"
I was able to come up with a solution for this problem, which can further refine as:
Retrieve all users with a given score or retrieve a single score for a single user.
What I determined was that using the namespace users is not a sufficient descriptor for both the score and user id. When using 2 different keys, it is clearly possible to get either a range or a single value. The downside is twice the writes I had hoped, but that is overall not a lot of overhead for me and the only way I found to properly retrieve both score and user.
ZADD score:users 0 10:1
ZADD score:users 0 10:2
ZADD score:users 0 5:3
ZADD users:score 0 1:10
ZADD users:score 0 2:10
ZADD users:score 0 3:5
ZRANGEBYLEX users:score [1: [1:\xff # "1:10"
ZRANGEBYLEX score:users [10: [10:\xff # "10:1" "10:2"
I'm using node redis to connect to redis.
The zscan function provided by redis does not return elements in order. I was wondering if there's a javascript library that helps me do that.
You can use the ZRANGE command to scan the sorted set. You only need to record how many elements you have already scanned.
// scan from the element with the smallest score (ascending order)
var index = 0
var count = 10
ZRANGE key index index + count - 1
index += count
ZRANGE key index index + count - 1
// until all elements have been scanned
With the ZREVRANGE command, you can also scan the sorted set in descending order.
First, I am new to Redis. Well let's say I have done:
127.0.0.1:6379> zadd subs:x 0 0
127.0.0.1:6379> zadd subs:x 500 500
127.0.0.1:6379> zadd subs:x 1000 1000
127.0.0.1:6379> zadd subs:x 5000 5000
127.0.0.1:6379> zadd subs:x 10000 10000
And I want to find an element that is just above the value 2000 and just below.
Above is simple and easy:
127.0.0.1:6379> ZRANGEBYSCORE subs:x 2000 +inf LIMIT 0 1
1) "5000"
But how to find an element below in simple way?
1) I know I can do:
127.0.0.1:6379> ZRANGEBYSCORE subs:x -inf 2000 LIMIT 2 1
1) "1000"
But I have to know before running this command that offset is 2 so in general I have to find offset first.
2) Or I can find ZRANK and then move one step backward:
127.0.0.1:6379> ZRANK subs:x 5000
(integer) 3
127.0.0.1:6379> ZRANGE subs:x 2 2
1) "1000"
So my question is there a simple way to get element just below a certain value?
Like above, but for below, use ZREVRANGEBYSCORE, you should.
Translation from Yoda-speak:
Redis actually features a command that does just what you're looking for - ZREVRANGEBYSCORE. ZREVRANGEBYSCORE does the same thing as ZRANGEBYSCORE but uses reverse ordering (as the "REV" in its name suggests).
That would allow you to get the "below 2000" member easily with just one call, as you've shown in your comment. May the force be with you.
I am new to sorted sets in Redis (3.0.2). I basically want to update my value in sorted sets of Redis based on unique key. As of now "zadd" each time keeps on adding new values to a specific key.
As of now:
127.0.0.1:6379> zadd xyz 1 "abc"
(integer) 1
127.0.0.1:6379> zadd xyz 1 "newabc"
(integer) 1
127.0.0.1:6379> zrange xyz 0 -1
1) "abc"
2) "newabc"
Required Output: (It should over write the xyz key's value from "abc" to "newabc"
127.0.0.1:6379> zadd xyz 1 "abc"
(integer) 1
127.0.0.1:6379> zadd xyz 1 "newabc"
(integer) 1
127.0.0.1:6379> zrange xyz 0 -1
1) "newabc"
A sorted set in Redis is a set when we talk about the element, while multiple different elements can coexist with the same score.
If you want that output, you'll need to design a different data model, and since I don't know your actual issue or what's your goal in your project, I won't be able to provide a clear solution.