redis - (错误)WRONGTYPE 键不是有效的 HyperLogLog 字符串值

Question

我正在使用 redis-cli 学习 HyperLogLogs 示例

The redis-cli examples show how you can use HyperLogLog commands to record and count unique user visits to a website.
The command PFADD adds one or many strings to a HyperLogLog. PFADD returns 1 if the cardinality was changed and 0 if it remains the same:

尽管如此，当我按照说明操作时它会报错:

127.0.0.1:6379> PFADD visits:2015-01-01 "carl" "max" "hugo" "arthur"
(error) WRONGTYPE Key is not a valid HyperLogLog string value.

Answer 1

错误是，即使简洁，也非常有用 - 您正在尝试使用不是 HLL 的现有 key (即 visits:2015-01-01)。

现有 key 可能是某种字符串，但如果您DEL visits:2015-01-01，您应该能够PFADD到它。