[BUG] Project Delete button has no effect

[Mohinta2892]

Hi @tomka,

I am trying to delete a project from the admin page.
Clicking on delete seems to have no effect. Interestingly, no errors are reported too.

What happens at the backend when we fire delete? I assume it tries to delete (clear out) postgres tables and therefore takes huge amount of time when num. of rows in the tables are high (can lead to OOM errors?).

BW,
Samia

[tomka]

Hi Samia, When deleting a project, CATMAID will try to delete all data associated with this project (or rather move it to history tables). Depending on the project size (in terms of treenodes, Synapsen, etc.) this can indeed take a while, like you already stated. How much data is associated with the project? Would you mind sharing the CATMAID instance name and the project ID so that I can have a look? If this is a large project, it might be easier to delete it directly from the server CLI. Best wishes, Tom Am 27. Mai 2026 11:43:09 MESZ schrieb Samia Mohinta ***@***.***>:

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Mohinta2892 created an issue (catmaid/CATMAID#2331) <img width="1176" height="291" alt="Image" src="https://github.com/user-attachments/assets/81eb48d7-78bd-4a02-8dc0-2ff90bb546fa" /> Hi @tomka, I am trying to delete a project from the admin page. Clicking on delete seems to have no effect. Interestingly, no errors are reported too. What happens at the backend when we fire delete? I assume it tries to delete (clear out) postgres tables and therefore takes huge amount of time when num. of rows in the tables are high. <img width="570" height="332" alt="Image" src="https://github.com/user-attachments/assets/136c63da-4ea6-4d81-95d3-85a7a1fba0b6" /> BW, Samia -- Reply to this email directly or view it on GitHub: #2331 You are receiving this because you were mentioned. Message ID: ***@***.***>

[Mohinta2892]

Hi @tomka,

thanks!

it is catmaid-fibsem, project_id 32 (project name: Octo ML Clone), as can be seen from the screenshot below:

It is has ~3M synapses in the connector table, that I was deleting directly via postgres (within transactions) based on notes from Albert.

However, we had a network downtime yesterday and the transaction rolledback.
If we can delete this via the CLI that would be amazing.

catmaid_fibsem=# select project_id, count(*) from connector group by project_id where project_id=32;
 project_id |  count  
         32 | 3054656

If you can also share some notes on how to delete via cli, that would be super helpful too.

[meesudzu]

PR submitted: #2332

The delete button was non-functional because the cancel.js script was loaded in the project deletion confirmation template, interfering with form submission. Removing that script reference restores the form's submit behavior.

[tomka]

Thanks for the details! Yeah I am sure 3M synapses won't be deleted super quickly and that you'll have to wait a moment. If the webserver allows this long running connection, there is no fundamental problem with it, because like all endpoints this is done within a transaction. However, since it is hard to know in advance how long this is going to take, I would probably attempt to delete such a project also via the CLI. I'd also use `psql` to issue a `DELETE FROM project WHERE id = 32;`, the proper cascading deletes (and history management) are handled within Postgres (rather than Django). The admin front-end however wants your confirmation and shows all rows referencing this project for you to check (including 3M synapses).

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On Wed, May 27, 2026 at 03:27:11AM -0700, Samia Mohinta wrote: Mohinta2892 left a comment (catmaid/CATMAID#2331) Hi @tomka, thanks! it is `catmaid-fibsem`, `project_id` **32** (project name: **Octo ML Clone**), as can be seen from the screenshot below: <img width="1346" height="46" alt="Image" src="https://github.com/user-attachments/assets/8f973718-733c-4b2f-97b2-dfb1664157c2" /> It is has ~3M synapses in the `connector` table, that I was deleting directly via `postgres` (within transactions) based on notes from Albert. However, we had a network downtime yesterday and the transaction rollbacked. If we can delete this via the CLI that would be amazing. ``` catmaid_fibsem=# select project_id, count(*) from connector group by project_id where project_id=32; project_id | count 32 | 3054656 ``` -- Reply to this email directly or view it on GitHub: #2331 (comment) You are receiving this because you were mentioned. Message ID: ***@***.***>

[Mohinta2892]

Hi @tomka,

Thank you, I am running into OOM errors, after triggering the delete via the webserver.
I can give it a try via CLI. Not sure, however, how to get around OOM errors.

[tomka]

I don't think that you can get around OOM errors when triggering the delete via the admin interface (apart from replacing the admin delete view/template). What you can do though is to directly call the API endpoint DELETE {project_id}/, which should issue the respective SQL (DELETE FROM project...) directly, rather than letting Django list all referenced items in the admin interface.