FastDateTime

Experimental optimized Delphi TDateTime functions.

These functions are used in TeeBI ultrafast queries when filtering or grouping-by datetime fields of millions of records.

Aproximate speed improvements, release-mode optimized compilation:

Windows 11:

32-bit x86 CPU (13th gen Intel):

Function	RAD 13.0 Florence	Lazarus / FreePascal
YearOf	41% faster	35% faster
MonthOf	28% faster	0% *
DayOf	28% faster	0% *
DayOfTheYear	52% faster	46% faster

• Lazarus RTL DateUtils functions are very fast, different algorithm

64-bit CPU:

Function	RAD 13.0 Florence	Lazarus / FreePascal
YearOf	82% faster	(slower, FPC 62% faster)
MonthOf	69% faster	(slower, FPC 200% faster)
DayOf	69% faster	(slower, FPC 200% faster)
DayOfTheYear	80% faster	(similar speed)

• Lazarus 64bit compiler gives faster execution

Linux Ubuntu 24.04.3 LTS

64-bit CPU:

Function	RAD 13.0 Florence
YearOf	55% faster
MonthOf	49% faster
DayOf	50% faster
DayOfTheYear	74% faster