NoSQL – Page 4

Redis ZREMRANGEBYSCORE Command Explained

January 12, 2023 by Ian

In Redis, the ZREMRANGEBYSCORE command enables us to remove all members from a sorted set with a score between a certain range.

Redis ZREMRANGEBYLEX Command Explained

January 11, 2023 by Ian

In Redis, the ZREMRANGEBYLEX command enables us to use a lexicographical range to remove members from a sorted set. That is, we can specify that all members between a given lexicographical range are removed.

This relies on all members having the same score (which forces lexicographical ordering).

Redis ZREM Command Explained

January 10, 2023 by Ian

In Redis, the ZREM command removes one or more members from the specified sorted set.

Fix “WRONGTYPE Operation against a key holding the wrong kind of value” when using ZUNION or ZUNIONSTORE in Redis

January 8, 2023 by Ian

If you get an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when using the ZUNION or ZUNIONSTORE commands in Redis, it’s because you’re passing a key with the wrong data type.

To fix this issue, make sure the keys you pass to these commands contain either sets or sorted sets. Although these commands are for sorted sets, they also work with non-sorted sets.

Redis ZINCRBY Command Explained

January 7, 2023 by Ian

In Redis, the ZINCRBY command increments the score of a given member in a sorted set.

Redis ZREVRANGE Replacement

January 6, 2023 by Ian

Starting with Redis 6.2.0, the ZRANGE command added the REV, BYSCORE, BYLEX and LIMIT options. The addition of the first three means that the ZRANGE command can now do what the ZREVRANGE, ZRANGEBYSCORE, ZREVRANGEBYSCORE, ZRANGEBYLEX and ZREVRANGEBYLEX commands can do.

As a result, those commands are now deprecated (as of Redis 6.2.0).

Therefore, we should no longer use the ZREVRANGE command when we need to return a sorted set in descending order. Instead, we should use the ZRANGE command with the REV argument.

Redis BZPOPMAX Command Explained

January 4, 2023 by Ian

In Redis, the BZPOPMAX command is the blocking variant of the ZPOPMAX command.

The BZPOPMAX command works similar to ZPOPMAX when any of the sorted sets contain elements. That is, it pops a member with the highest score from the sorted set.

Redis BZPOPMIN Command Explained

January 4, 2023 by Ian

In Redis, the BZPOPMIN command is the blocking variant of the ZPOPMIN command.

The BZPOPMIN command works similar to ZPOPMIN when any of the sorted sets contain elements. That is, it pops a member with the lowest score from the sorted set.

Redis ZPOPMAX Command Explained

January 4, 2023January 3, 2023 by Ian

In Redis, the ZMPOPMAX command removes and returns (pops) members with the highest scores from the specified sorted set. By default it pops one member, but we can also specify how many members we want to pop.

Redis ZPOPMIN Command Explained

January 4, 2023January 3, 2023 by Ian

In Redis, the ZMPOPMIN command removes and returns (pops) members with the lowest scores from the specified sorted set. By default it pops one member, but we can also specify how many members we want to pop.