Redis Manifesto

在Redis源代码目录下面有个MANIFESTO文件。我觉得最后一点写的很有意思：“写代码时间很费神的事情。如果从写代码中没有办法获取快乐的话，那么最好立刻停止。”

[Note: this is the Redis manifesto, for general information about
       installing and running Redis read the README file instead.]

Redis Manifesto
===============

1 - A DSL for Abstract Data Types. Redis is a DSL (Domain Specific Language)
    that manipulates abstract data types and implemented as a TCP daemon.
    Commands manipulate a key space where keys are binary-safe strings and
    values are different kinds of abstract data types. Every data type
    represents an abstract version of a fundamental data structure. For instance
    Redis Lists are an abstract representation of linked lists. In Redis, the
    essence of a data type isn't just the kind of operations that the data types
    support, but also the space and time complexity of the data type and the
    operations performed upon it.

2 - Memory storage is #1. The Redis data set, composed of defined key-value
    pairs, is primarily stored in the computer's memory. The amount of memory in
    all kinds of computers, including entry-level servers, is increasing
    significantly each year. Memory is fast, and allows Redis to have very
    predictable performance. Datasets composed of 10k or 40 millions keys will
    perform similarly. Complex data types like Redis Sorted Sets are easy to
    implement and manipulate in memory with good performance, making Redis very
    simple. Redis will continue to explore alternative options (where data can
    be optionally stored on disk, say) but the main goal of the project remains
    the development of an in-memory database.

3 - Fundamental data structures for a fundamental API. The Redis API is a direct
    consequence of fundamental data structures. APIs can often be arbitrary but
    not an API that resembles the nature of fundamental data structures. If we
    ever meet intelligent life forms from another part of the universe, they'll
    likely know, understand and recognize the same basic data structures we have
    in our computer science books. Redis will avoid intermediate layers in API,
    so that the complexity is obvious and more complex operations can be
    performed as the sum of the basic operations.

4 - Code is like a poem; it's not just something we write to reach some
    practical result. Sometimes people that are far from the Redis philosophy
    suggest using other code written by other authors (frequently in other
    languages) in order to implement something Redis currently lacks. But to us
    this is like if Shakespeare decided to end Enrico IV using the Paradiso from
    the Divina Commedia. Is using any external code a bad idea? Not at all. Like
    in "One Thousand and One Nights" smaller self contained stories are embedded
    in a bigger story, we'll be happy to use beautiful self contained libraries
    when needed. At the same time, when writing the Redis story we're trying to
    write smaller stories that will fit in to other code.

5 - We're against complexity. We believe designing systems is a fight against
    complexity. We'll accept to fight the complexity when it's worthwhile but
    we'll try hard to recognize when a small feature is not worth 1000s of lines
    of code. Most of the time the best way to fight complexity is by not
    creating it at all.

6 - Two levels of API. The Redis API has two levels: 1) a subset of the API fits
    naturally into a distributed version of Redis and 2) a more complex API that
    supports multi-key operations. Both are useful if used judiciously but
    there's no way to make the more complex multi-keys API distributed in an
    opaque way without violating our other principles. We don't want to provide
    the illusion of something that will work magically when actually it can't in
    all cases. Instead we'll provide commands to quickly migrate keys from one
    instance to another to perform multi-key operations and expose the tradeoffs
    to the user.

7 - We optimize for joy. We believe writing code is a lot of hard work, and the
    only way it can be worth is by enjoying it. When there is no longer joy in
    writing code, the best thing to do is stop. To prevent this, we'll avoid
    taking paths that will make Redis less of a joy to develop.