ClickHouse/utils/convert-month-partitioned-parts
Vasily Nemkov 2d03d330bc Extended range of DateTime64 to years 1925 - 2238
The Year 1925 is a starting point because most of the timezones
switched to saner (mostly 15-minutes based) offsets somewhere
during 1924 or before. And that significantly simplifies implementation.

2238 is to simplify arithmetics for sanitizing LUT index access;
there are less than 0x1ffff days from 1925.

* Extended DateLUTImpl internal LUT to 0x1ffff items, some of which
  represent negative (pre-1970) time values.
  As a collateral benefit, Date now correctly supports dates up to 2149
  (instead of 2106).
* Added a new strong typedef ExtendedDayNum, which represents dates
  pre-1970 and post 2149.
* Functions that used to return DayNum now return ExtendedDayNum.
* Refactored DateLUTImpl to untie DayNum from the dual role of being
  a value and an index (due to negative time). Index is now a different
  type LUTIndex with explicit conversion functions from DatNum, time_t,
  and ExtendedDayNum.
* Updated DateLUTImpl to properly support values close to epoch start
  (1970-01-01 00:00), including negative ones.
* Reduced resolution of DateLUTImpl::Values::time_at_offset_change
  to multiple of 15-minutes to allow storing 64-bits of time_t in
  DateLUTImpl::Value while keeping same size.
* Minor performance updates to DateLUTImpl when building month LUT
  by skipping non-start-of-month days.
* Fixed extractTimeZoneFromFunctionArguments to work correctly
  with DateTime64.
* New unit-tests and stateless integration tests for both DateTime
  and DateTime64.
2021-02-24 17:08:35 +02:00
..
CMakeLists.txt
main.cpp