# Historizing a large JSON string tag

**URL:** <https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146>\
**Category:** Ignition\
**Tags:** ignition79, database\
**Created:** [February 26, 2018, 9:57pm UTC](https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146 "2018-02-26T21:57:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![roger\_larson](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/roger_larson/32/8574_2.png) [@roger\_larson](https://forum.inductiveautomation.com/u/roger_larson)\
**Post date:** [February 26, 2018, 9:57pm UTC](https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146/1 "2018-02-26T21:57:38Z")

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Hi all,

I have a problem storing data from a tag containing a JSON string (or Python dictionary, if you will) within Ignition. Generally, the string exceeds the VARCHAR(255) character limit that is implemented in the tag historian tables (stringvalue column). Thus, a MySQL table cannot accept the value and refuses to historize it, causing the values to aggregate in store and forward.

I also cannot automate an alteration of that table column to VARCHAR(8191) or whatever, since tables are partitioned by day and millions of rows are being stored - tables that already exist are difficult to modify without errors, this may be unreliable.

Anyone have a good, alternative solution to this? Breaking the JSON string up into multiple columns? Turning the data into tags?

Best Regards,  
Roger

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**Author:** ![misael.lopez](https://avatars.discourse-cdn.com/v4/letter/m/b9e5f3/32.png) [@misael.lopez](https://forum.inductiveautomation.com/u/misael.lopez)\
**Post date:** [February 26, 2018, 10:48pm UTC](https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146/2 "2018-02-26T22:48:02Z")

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You could probably create an expression tag which you can use to break up the string. Using the split function in the Expression editor, you can convert it into a dataset and extract the data you need from there. This is assuming the data in JSON format was converted into a string before hand.

Split function: [https://docs.inductiveautomation.com/display/DOC/split](https://docs.inductiveautomation.com/display/DOC/split)

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [February 26, 2018, 10:50pm UTC](https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146/3 "2018-02-26T22:50:03Z")

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You can turn the data into tags using the `jsonGet` expression function.

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**Author:** ![drewdin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/drewdin/32/3363_2.png) [@drewdin](https://forum.inductiveautomation.com/u/drewdin)\
**Post date:** [November 17, 2025, 10:42pm UTC](https://forum.inductiveautomation.com/t/historizing-a-large-json-string-tag/17146/4 "2025-11-17T22:42:36Z")

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Is there a similar jsonPut? that takes a list of tags and makes JSON sting?