doc cache: clarifications around cache backends

There's only one backend and no other is even in long-term plans.
There used to be some networked backend, but due to synchronous internal
usage of cache these suffered from bad latency and were removed.

diff --git a/daemon/bindings/cache.rst b/daemon/bindings/cache.rst
index 7c2821bb022b88b59822a558a349ff7c6249bd9a..d255e866178d7bad3842e684fb8e20fda68e7cf8 100644 (file)
--- a/daemon/bindings/cache.rst
+++ b/daemon/bindings/cache.rst
@@ -97,7 +97,7 @@ Configuration reference
 
    .. tip:: Use ``kB, MB, GB`` constants as a multiplier, e.g. ``100*MB``.
 
-   As of now, the built-in backend with URI ``lmdb://`` allows you to change the cache directory.
+   The URI ``lmdb://path`` allows you to change the cache directory.
 
    Example:
 
@@ -143,6 +143,8 @@ Configuration reference
 
    :return: map of backends
 
+   .. note:: For now there is only one backend implementation, even though the APIs are ready for different (synchronous) backends.
+
    The cache supports runtime-changeable backends, using the optional :rfc:`3986` URI, where the scheme
    represents backend protocol and the rest of the URI backend-specific configuration. By default, it
    is a ``lmdb`` backend in working directory, i.e. ``lmdb://``.