# Transaction group vs query tag - re: resource utilization

**URL:** <https://forum.inductiveautomation.com/t/transaction-group-vs-query-tag-re-resource-utilization/17380>\
**Category:** Ignition\
**Tags:** scripting, database, ignition79\
**Created:** [March 15, 2018, 6:17pm UTC](https://forum.inductiveautomation.com/t/transaction-group-vs-query-tag-re-resource-utilization/17380 "2018-03-15T18:17:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![AIO](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/aio/32/87549_2.png) [@AIO](https://forum.inductiveautomation.com/u/AIO)\
**Post date:** [March 15, 2018, 6:17pm UTC](https://forum.inductiveautomation.com/t/transaction-group-vs-query-tag-re-resource-utilization/17380/1 "2018-03-15T18:17:17Z")

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Hey folks,

I’ve got some general design / efficiency questions I’m hoping you may be able to help with.

We have several hundred tanks, each with identical tags, that we’re logging data on (not tag history). Each tank has about a dozen tags associated with it.

Previously we were using transaction groups, but shifted to a query tag included in the UDT (for ease of editing / control). My question has to do with the system overhead associated with both of these and other options (gateway event script?).

Is there a best practice or design consideration to be had when choosing between these methods?

7.9.2 (x64), 1.8.0\_144

Much appreciated.  
Cheers,  
Andrew

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**Author:** ![cmaynes](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/cmaynes/32/6852_2.png) [@cmaynes](https://forum.inductiveautomation.com/u/cmaynes)\
**Post date:** [May 19, 2020, 4:18pm UTC](https://forum.inductiveautomation.com/t/transaction-group-vs-query-tag-re-resource-utilization/17380/2 "2020-05-19T16:18:41Z")

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I am also wondering about this. What the trade-offs? Which is recommended when?

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**Author:** ![AIO](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/aio/32/87549_2.png) [@AIO](https://forum.inductiveautomation.com/u/AIO)\
**Post date:** [May 19, 2020, 4:35pm UTC](https://forum.inductiveautomation.com/t/transaction-group-vs-query-tag-re-resource-utilization/17380/3 "2020-05-19T16:35:19Z")

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While I've not received a specific answer to this query, last consensus was that only updating when data had changed was optimal, using either a tag change script or a gateway script to manage it. Here's the latest thread that touched these queries.

> [@\[bug-15464\]Query Tags running Update statements execute but display as errored](http://forum.inductiveautomation.com/t/bug-15464-query-tags-running-update-statements-execute-but-display-as-errored/30007/5):
>
> While I don’t disagree with Phil about unconditional updates to the DB, this is actually supported - there’s code on the backend to attempt to determine the query type, and issue it to the db as an update/select appropriately- and there’s also a manual query type override, that we’re just not exposing in the UI - I’m not sure why. @AIO, I can’t guarantee this will work, but if you right click the tag, select ‘Edit (raw)’, and then add a queryType: Update property, do you still get the error on …