SysDB — System DataBase

Include priority when printing log messages.

Fixed handling of empty queries.

When serializing the entire store (LIST command), return an array of host objects (rather than wrapping it into another object).

Fixed JSON format of time-series data.

Fixed error checks of invalid compare expressions and reject them.

Fixed lookups by back-end name.

Added support for comparing attributes with different types by comparing their string values.

Clarified details about asynchronous messages and authentication options and made client implementation more robust.

Introduced a new message type encoding the JSON serialized response of a query and its data type.

Include the priority in log messages.

Include object types in FETCH, LIST, and LOOKUP messages.

Added support for including services and metrics in LIST responses and skip hosts without the respective children.

Added support for services and metrics to LIST command.

Changed syntax for attribute lookup to attributes[<name>].

Changed syntax for accessing queryable fields to .<field>.

strbuf: Improved memory management.