# Historian Data At Different Frequencies

**URL:** <https://forum.inductiveautomation.com/t/historian-data-at-different-frequencies/56688>\
**Category:** Ignition\
**Tags:** ignition81, database\
**Created:** [March 1, 2022, 10:04pm UTC](https://forum.inductiveautomation.com/t/historian-data-at-different-frequencies/56688 "2022-03-01T22:04:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![michael.thompson](https://avatars.discourse-cdn.com/v4/letter/m/df788c/32.png) [@michael.thompson](https://forum.inductiveautomation.com/u/michael.thompson)\
**Post date:** [March 1, 2022, 10:04pm UTC](https://forum.inductiveautomation.com/t/historian-data-at-different-frequencies/56688/1 "2022-03-01T22:04:08Z")

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I have a project that requires the historian to store data at a frequency of \< 10 seconds for 6 months. Data after 6 months can be 1 minute data. I want to avoid storing \< 10s data forever. I am thinking possibly using preprocessing on the database connection to a 60-second interval, disabling data pruning, and have the DBMS prune the \< 10 second data that is \> 6 month old. Will it break the Ignition trending to be missing the raw tables, but not the preprocessed tables?  
Running Ignition 8.1x with MSSQL.

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**Author:** ![CosmoStevens](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/cosmostevens/32/32309_2.png) [@CosmoStevens](https://forum.inductiveautomation.com/u/CosmoStevens)\
**Post date:** [March 3, 2022, 5:39pm UTC](https://forum.inductiveautomation.com/t/historian-data-at-different-frequencies/56688/2 "2022-03-03T17:39:59Z")

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I can’t say for certain whether it would work or not. Trending will only work if all of [these](https://docs.inductiveautomation.com/display/DOC80/Ignition+Auto-Generated+SQL+Tables) tables are intact. I would say thoroughly test this before implementing it.

One way to implement this through Ignition would be to store two different sets of history for the tag: one every \< 10 seconds, one every minute. Then set the \< 10 seconds history to prune every six months. This may take up more storage space up front, but it will be much less of a hassle, and it will definitely work.