# multiple atomic transactions

**URL:** <https://forum.djangoproject.com/t/multiple-atomic-transactions/25797>\
**Category:** Using the ORM\
**Created:** [November 30, 2023, 6:31pm UTC](https://forum.djangoproject.com/t/multiple-atomic-transactions/25797 "2023-11-30T18:31:40Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ShervinAbd92](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/shervinabd92/32/17477_2.png) [@ShervinAbd92](https://forum.djangoproject.com/u/ShervinAbd92)\
**Post date:** [November 30, 2023, 6:31pm UTC](https://forum.djangoproject.com/t/multiple-atomic-transactions/25797/1 "2023-11-30T18:31:40Z")

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Can Django application run multiple atomic transactions each locking/modifying only a specific row, as opposed to the whole table, on my MySQL database?  
We are running a Django server with RabbitMQ and Celery. We have Parent objects which are tied to Children (These objects are actually the same Model, but used differently). When new children are added, they perform a merge operation which updates the parent. If we receive children A, B, and C, we make a new merged version for each. A, then A+B, then AB+C. The current state of this process can be seen on the Parent object. The trouble comes if a second child arrives before the merge process for the first has concluded. This results in [A, B, B+C] instead of [A, A+B, AB+C]. Is there a way to lock the row of one Parent object only, while still allowing multiple separate Parent/Child operations simultaneously?

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**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [November 30, 2023, 7:25pm UTC](https://forum.djangoproject.com/t/multiple-atomic-transactions/25797/2 "2023-11-30T19:25:15Z")

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You should be able to use a [`select_for_update`](https://docs.djangoproject.com/en/4.2/ref/models/querysets/#select-for-update) to retrieve the rows for your merge operation.

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<div class="post-metadata">

**Author:** ![ShervinAbd92](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/shervinabd92/32/17477_2.png) [@ShervinAbd92](https://forum.djangoproject.com/u/ShervinAbd92)\
**Post date:** [December 4, 2023, 5:20pm UTC](https://forum.djangoproject.com/t/multiple-atomic-transactions/25797/3 "2023-12-04T17:20:16Z")

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so I do lock the first parent object with the select\_for\_update call for its merge, however while the transaction is running, i get a 2nd and 3rd parent objects from a different query submission and what it seems to be happening that they will go under the same transaction waiting for the process to be done, but soon timeout. i get the error msg **django.db.utils.OperationalError: (1205, ‘Lock wait timeout exceeded; try restarting transaction’)**

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<div class="post-metadata">

**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 4, 2023, 5:58pm UTC](https://forum.djangoproject.com/t/multiple-atomic-transactions/25797/4 "2023-12-04T17:58:31Z")

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