html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/datasette/pull/2008#issuecomment-1407733793,https://api.github.com/repos/simonw/datasette/issues/2008,1407733793,IC_kwDOBm6k_c5T6FAh,9599,simonw,2023-01-29T18:17:40Z,2023-01-29T18:17:40Z,OWNER,"> We don't have any performance tests yet - would be a useful thing to add, I've not built anything like that before (at least not in CI, I've always done as-hoc performance testing using something like Locust) so I don't have a great feel for how it could work.
Had an interesting conversation about this just now: https://fedi.simonwillison.net/@simon/109773800944614366
There's a risk that different runs will return different results due to the shared resource nature of GitHub Actions runners, but a good fix for that is to run comparative tests where you run the benchmark against e.g. both `main` and the incoming PR branch and report back on any differences.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1560982210,array facet: don't materialize unnecessary columns,
https://github.com/simonw/datasette/pull/2008#issuecomment-1407716963,https://api.github.com/repos/simonw/datasette/issues/2008,1407716963,IC_kwDOBm6k_c5T6A5j,193185,cldellow,2023-01-29T17:04:03Z,2023-01-29T17:04:03Z,CONTRIBUTOR,"Performance tests - I think most places don't have them as a formal gate enforced by CI. TypeScript and scalac seem to have tests that run to capture timings. The timings are included by a bot as a comment or build check, and also stored in a database so you can graph changes over time to spot regressions. Probably overkill for Datasette!
Window functions - oh, good point. Looks like Ubuntu shipped JSON1 support as far back as sqlite 3.11. I'll let this PR linger until there's a way to run against different SQLite versions. For now, I'm shipping this with `datasette-ui-extras`, since I think it's OK for a plugin to enforce a higher minimum requirement.
Tests - there actually did end up being test changes to capture the undercount bug of the current implementation, so the current implementation would fail against the new tests.
Perhaps a non-window function version could be written that uses `random()` instead of `row_number() over ()` in order to get a unique key. It's technically not unique, but in practice, I imagine it'll work well.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1560982210,array facet: don't materialize unnecessary columns,
https://github.com/simonw/datasette/pull/2008#issuecomment-1407568923,https://api.github.com/repos/simonw/datasette/issues/2008,1407568923,IC_kwDOBm6k_c5T5cwb,9599,simonw,2023-01-29T05:47:36Z,2023-01-29T05:47:36Z,OWNER,"> I don't know how/if you do automated tests for performance, so I haven't changed any of the tests.
We don't have any performance tests yet - would be a useful thing to add, I've not built anything like that before (at least not in CI, I've always done as-hoc performance testing using something like Locust) so I don't have a great feel for how it could work.
I see not having to change the tests at all for this change as a really positive sign. If you find any behaviour differences between this and the previous that's a sign we should add a mother test or two specifying the behaviour we want.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1560982210,array facet: don't materialize unnecessary columns,
https://github.com/simonw/datasette/pull/2008#issuecomment-1407567753,https://api.github.com/repos/simonw/datasette/issues/2008,1407567753,IC_kwDOBm6k_c5T5ceJ,9599,simonw,2023-01-29T05:39:54Z,2023-01-29T05:40:34Z,OWNER,"I absolutely _love_ this performance boost - really nice find.
One concern: this will be the first time Datasette ships a core feature that uses window functions.
Window functions were added to SQLite in [version 3.25.0](https://www.sqlite.org/releaselog/3_25_0.html) on 2018-09-15 - which means it's still very common for Datasette to run on versions that don't yet support them.
So I see two options:
- Detect window function support and switch between the old implementation and this better, new one
- Detect window functions and disable the facet-by-JSON feature entirely if they are missing
I like the first option a bit better.
This also leads to a tricky CI challenge: Datasette needs to be able to run its test suite against more than one SQLite version to confidently test this feature going forward.
I don't yet have a good GitHub Actions recipe for this, but I _really_ need one - for `sqlite-utils` too.
Might be able to use this trick for that: https://til.simonwillison.net/sqlite/ld-preload","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1560982210,array facet: don't materialize unnecessary columns,
https://github.com/simonw/datasette/pull/2008#issuecomment-1407471459,https://api.github.com/repos/simonw/datasette/issues/2008,1407471459,IC_kwDOBm6k_c5T5E9j,22429695,codecov[bot],2023-01-28T19:40:18Z,2023-01-29T04:55:39Z,NONE,"# [Codecov](https://codecov.io/gh/simonw/datasette/pull/2008?src=pr&el=h1&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison) Report
Base: **92.11**% // Head: **91.78**% // Decreases project coverage by **`-0.34%`** :warning:
> Coverage data is based on head [(`f529a30`)](https://codecov.io/gh/simonw/datasette/pull/2008?src=pr&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison) compared to base [(`e4ebef0`)](https://codecov.io/gh/simonw/datasette/commit/e4ebef082de90db4e1b8527abc0d582b7ae0bc9d?el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison).
> Patch has no changes to coverable lines.
Additional details and impacted files
```diff
@@ Coverage Diff @@
## main #2008 +/- ##
==========================================
- Coverage 92.11% 91.78% -0.34%
==========================================
Files 38 39 +1
Lines 5555 5599 +44
==========================================
+ Hits 5117 5139 +22
- Misses 438 460 +22
```
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|---|---|---|
| [datasette/facets.py](https://codecov.io/gh/simonw/datasette/pull/2008?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison#diff-ZGF0YXNldHRlL2ZhY2V0cy5weQ==) | `91.84% <ø> (ø)` | |
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