Clojurians Log v2

I’ve experimented a little, comparing v3-alpha-2025-07-11 and v3-alpha-00120400. In Chrome I’ve looked at how the JS Heap size and DOM Nodes values change when I repeatedly toggle my app’s timeline chart. I see that: • The number of DOM nodes steadily increases in both versions in much the same way. • The JS Heap size stays much the same with v3-alpha-2025-07-11, but continually increases with v3-alpha-00120400. • The v3-alpha-00120400 version responds more and more slowly the more I toggle the chart. See the table below for the numbers I collected. I see similar behaviour with toggling the app’s Table of Contents pane, which has an e/for-by very similar to the one for the chart that I linked to in my previous message. I’m happy to fiddle with my code to see if I can make anything change, but if this info sheds any light on things or if you have any suggestions for things I could try, please let me know.

|                            |                       |                              |
|----------------------------+--------------------------+---------------------------------|
| When                       |      v3-alpha-2025-07-11 |               v3-alpha-00120400 |
|                            | JS Heap size / DOM Nodes |        JS Heap size / DOM Nodes |
|----------------------------+--------------------------+---------------------------------|
| Initial load with no panes |        70 MB /        65 |               78 MB /        65 |
|                            |                          |                                 |
| After show chart           |       410 MB /       675 |              500 MB /       678 |
| After hide chart           |       410 MB /       752 |              490 MB /       755 |
|                            |                          |                                 |
| After show chart           |       422 MB /     1,293 |              700 MB /     1,257 |
| After hide chart           |       420 MB /     1,370 |              700 MB /     1,334 |
|                            |                          |                                 |
| After show chart           |       434 MB /     1,836 |              917 MB /     1,836 |
| After hide chart           |       434 MB /     1,913 |              919 MB /     1,913 |
|                            |                          |                                 |
| (5 more toggles)           |                          |                                 |
| After show chart           |       250 MB /     3,369 |            1,200 MB /     3,747 |
|                            |                          |                                 |
| (6 more toggles)           |                          |                                 |
| After show chart           |       450 MB /     7,730 |            2,700 MB /     8,000 |
| After hide chart           |                          |                                 |
|                            |                          |                                 |
| (6 more toggles)           |                          |                                 |
| After show chart           |       465 MB /    10,500 |            3,500 MB /    10,000 |
|                            |                          |                                 |
|                            |                          |    This is about half the speed |
|                            |                          |                                 |
|                            |                          | I left this for ~30 minutes and |
|                            |                          |  the numbers remained the same. |
|----------------------------+--------------------------+---------------------------------|

I’ve come up with a simple example that shows the same kind of behaviour. It’s an app that repeatedly toggles the showing of many nodes. • The number of DOM nodes continually increases, with both v3-alpha-2025-07-11 and v3-alpha-00120400. • The heap size continually increases, but less fast with v3-alpha-2025-07-11 than v3-alpha-00120400. Here’s the code…

Here’s screenshot for v3-alpha-2025-07-11:

And a screenshot for v3-alpha-00120400:

Hi. Is memory leak still a known problem? I've tried the above many-elements code with the latest release (v3-alpha-d8066cb0), and although things are better than with the November release (v3-alpha-00120400) they're still worse than with last July's release (v3-alpha-2025-07-11).

we have at least one known dom leak

i have re-raised this issue with the team, we have been investing in test infrastructure upgrades this year

Great; thank you. (I’m not complaining; just wanted to be sure you still think there’s an issue.)

yes of course, all good

i can say a bit more, i think we have ~3 known electric core bugs total, but none are trivial to fix. the first was a missionary layer issue in the discrete flows, these have been rewritten and are almost delivered. The second is in the differential "incseq" layer, these are also rewritten last fall but landing them was blocked on the missionary issue. So a bunch of stuff is stacked up. The rewritten incseqs also we expect to fix the e/for performance problems or at least be the basis for the fix

My Electric dependency is:

{:deps    {com.hyperfiddle/electric
           {:git/url ""
            :git/sha "85bbbbc2f27fe84452bbfc68db2771f3323214c3"
            :git/tag "v3-alpha-SNAPSHOT-2025-07-11"}
           ...

Is it possible for me to use the July version?

Yes, try with {:mvn/version "v3-alpha-2025-07-11"}.

We want to address this memory leak. Could you please tell us more? How are those many elements mounted and unmounted?

Thanks, that’s working. I’ll tell you more about the memory leak in a while (maybe in a few days). My time is a bit limited just at the moment.

Sure, np. Thank you for reporting 👍 For the records, we only identified one memory leak (detached DOM nodes still referenced) in an old demo, and this memory leak predates the current release.

If you want to look at things before I get back to you… • You and Dustin have access to my repo at GitHub. • The code that mounts the elements is at https://github.com/simon-katz/nomis-timelines-ec3/blob/332e7b124c361d04fb1c67c2716f4423833c7a04/src/nomis_timelines/chart.cljc#L72-L97 But of course I don’t expect you to look at things before I look into it a bit myself. Just if you want to, you can.

EDIT: Changed above link to cover more lines.