Hash Tables
Refer to https://swsmile.info/post/data-structure-hash-table/
...【Prometheus】Recording Rules
Recording Rules
Prometheus supports two types of rules which may be configured and then evaluated at regular intervals: recording rules and alerting rules. To include rules in Prometheus, create a file containing the necessary rule statements and have Prometheus load the file via the rule_files field in the Prometheus configuration. Rule files use YAML.
Recording rules allow you to precompute frequently needed or computationally expensive expressions and save their result as a new set of time series. Querying the precomputed result will then often be much faster than executing the original expression every time it is needed. This is especially useful for dashboards, which need to query the same expression repeatedly every time they refresh.
...【Redis】数据类型（Data Types）
Strings
Strings are the most basic kind of Redis value. Redis Strings are binary safe, this means that a Redis string can contain any kind of data, for instance a JPEG image or a serialized Ruby object.
A String value can be at max 512 Megabytes in length.
You can do a number of interesting things using strings in Redis, for instance you can:
- Use Strings as atomic counters using commands in the INCR family: INCR, DECR, INCRBY.
- Append to strings with the APPEND command.
- Use Strings as a random access vectors with GETRANGE and SETRANGE.
- Encode a lot of data in little space, or create a Redis backed Bloom Filter using GETBIT and SETBIT.
