* Database engine prototype version 0
* Database engine initial integration with netdata POC
* Scalable database engine with file and memory management.
* Database engine integration with netdata
* Added MIN MAX definitions to fix alpine build of travis CI
* Bugfix for backends and new DB engine, remove useless rrdset_time2slot() calls and erroneous checks
* DB engine disk protocol correction
* Moved DB engine storage file location to /var/cache/netdata/{host}/dbengine
* Fix configure to require openSSL for DB engine
* Fix netdata daemon health not holding read lock when iterating chart dimensions
* Optimized query API for new DB engine and old netdata DB fallback code-path
* netdata database internal query API improvements and cleanup
* Bugfix for DB engine queries returning empty values
* Added netdata internal check for data queries for old and new DB
* Added statistics to DB engine and fixed memory corruption bug
* Added preliminary charts for DB engine statistics
* Changed DB engine ratio statistics to incremental
* Added netdata statistics charts for DB engine internal statistics
* Fix for netdata not compiling successfully when missing dbengine dependencies
* Added DB engine functional test to netdata unittest command parameter
* Implemented DB engine dataset generator based on example.random chart
* Fix build error in CI
* Support older versions of libuv1
* Fixes segmentation fault when using multiple DB engine instances concurrently
* Fix memory corruption bug
* Fixed createdataset advanced option not exiting
* Fix for DB engine not working on FreeBSD
* Support FreeBSD library paths of new dependencies
* Workaround for unsupported O_DIRECT in OS X
* Fix unittest crashing during cleanup
* Disable DB engine FS caching in Apple OS X since O_DIRECT is not available
* Fix segfault when unittest and DB engine dataset generator don't have permissions to create temporary host
* Modified DB engine dataset generator to create multiple files
* Toned down overzealous page cache prefetcher
* Reduce internal memory fragmentation for page-cache data pages
* Added documentation describing the DB engine
* Documentation bugfixes
* Fixed unit tests compilation errors since last rebase
* Added note to back-up the DB engine files in documentation
* Added codacy fix.
* Support old gcc versions for atomic counters in DB engine
* optimized ses and added des
* added coefficient of variation
* fix bug identified by @vlvkobal: use all available points when resampling is required and the timeframe is not enough for a single point
* modularized exporters
* modularized API data queries
* optimized queries
* modularized API data reduction methods
* modularized api queries
* added new directories in makefiles
* added median db query
* moved all RRDR_GROUPING related to query.h
* added stddev query
* operational median and stddev
* working simple exponential smoothing
* too complex to do it right
* fixed ses
* fixed ses
* rewrote query engine
* fix double-exponential-smoothing
* cleanup
* fixed bug identified by @vlvkobal at rrdset_first_slot()
* enable freeipmi on systems with libipmimonitoring; #4440
