TIMESTAMP

TimeStamp refers to a datum that records a specific moment in time. In computing, a timestamp is typically a numeric value or a string that encodes date and time and can be used to order events, index data, or annotate records. A common form is the Unix timestamp, defined as the number of seconds elapsed since the Unix epoch at 00:00:00 UTC on 1 January 1970, with optional fractional part for sub-second precision.

Formats and representations vary. The most interoperable representations are ISO 8601 and RFC 3339 strings, such as 2024-12-31T23:59:59Z or 2024-12-31T23:59:59+00:00. Numeric timestamps include Unix time in seconds or milliseconds since the epoch, and higher precision variants in microseconds or nanoseconds. Some systems use alternative bases, such as Windows FILETIME, which measures intervals since a different epoch.

Usage and applications are broad. Timestamps underpin logging, versioning, database keys, file systems, and time-series data. They enable ordering, comparisons, and time-based queries. Precision and time zone handling are important, with Coordinated Universal Time (UTC) commonly used to avoid ambiguity; local time representations may require conversions for display.

Challenges include clock synchronization across systems, leap seconds, and clock drift. For measuring elapsed durations, monotonic clocks are preferred, while for absolute moments, reliable wall-clock time with a stable time source is needed.