is an option for various functions that specifies when a persistent value should be treated as expired.
PersistenceTime
is an option for various functions that specifies when a persistent value should be treated as expired.
Details
- PersistenceTime can be used for PersistentSymbol and InitializationValue .
- Values can be given as relative times in seconds or relative date and time specifications.
- Values are typically converted to absolute times based on the current time.
- The value Infinity () can be used to specify that a persistent value should never expire.
- An expired persistent value is treated as nonexistent, and the underlying persistent object may be removed.
Examples
open all close allBasic Examples (1)
Define a persistent value that expires in 5 seconds:
After 5 seconds, it is no longer used:
Scope (2)
Define a persistent value that expires in 1 minute:
Numbers are treated as seconds:
Define a persistent value that expires in 5 days:
A persistence time of Infinity causes the value to never expire:
Properties & Relations (2)
Values specified with PersistenceTime are converted to absolute expiration dates:
The default setting for PersistenceTime is to never expire:
See Also
History
Text
Wolfram Research (2017), PersistenceTime, Wolfram Language function, https://reference.wolfram.com/language/ref/PersistenceTime.html.
CMS
Wolfram Language. 2017. "PersistenceTime." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/PersistenceTime.html.
APA
Wolfram Language. (2017). PersistenceTime. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/PersistenceTime.html
BibTeX
@misc{reference.wolfram_2025_persistencetime, author="Wolfram Research", title="{PersistenceTime}", year="2017", howpublished="\url{https://reference.wolfram.com/language/ref/PersistenceTime.html}", note=[Accessed: 09-January-2026]}
BibLaTeX
@online{reference.wolfram_2025_persistencetime, organization={Wolfram Research}, title={PersistenceTime}, year={2017}, url={https://reference.wolfram.com/language/ref/PersistenceTime.html}, note=[Accessed: 09-January-2026]}