Utility methods for FlatKV cache

[cody-littley]

Describe your changes and provide context

Implements several utilities needed for the FlatKV cache.

Testing performed to validate your change

Unit tests, tested on branch that has integrated cache

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Mar 12, 2026, 2:23 PM

[codecov]

Codecov Report

❌ Patch coverage is 86.79245% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.36%. Comparing base (04faa6c) to head (e6ec6f4).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
sei-db/common/threading/adhoc_pool.go	45.45%	4 Missing and 2 partials ⚠️
sei-db/common/threading/elastic_pool.go	86.48%	4 Missing and 1 partial ⚠️
sei-db/common/threading/fixed_pool.go	91.89%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3055      +/-   ##
==========================================
+ Coverage   58.26%   58.36%   +0.10%     
==========================================
  Files        2072     2082      +10     
  Lines      171414   171146     -268     
==========================================
+ Hits        99882    99897      +15     
+ Misses      62602    62313     -289     
- Partials     8930     8936       +6     

Flag	Coverage Δ
sei-chain-pr	67.12% <86.79%> (?)
sei-db	70.41% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-db/common/threading/chan_utils.go	100.00% <100.00%> (ø)
sei-db/wal/wal.go	64.67% <100.00%> (-4.51%)	⬇️
sei-db/common/threading/fixed_pool.go	91.89% <91.89%> (ø)
sei-db/common/threading/elastic_pool.go	86.48% <86.48%> (ø)
sei-db/common/threading/adhoc_pool.go	45.45% <45.45%> (ø)

... and 248 files with indirect coverage changes

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[yzang2019]

Seems currently not being used, are we gonna add metrics for that in the future

[cody-littley]

Yes, the plan was to add metrics, but I didn't get to that as a part of this PR. I still want to add them eventually, though.

What is your preference? I'm ok with either deleting this until we need (not that much work to add later), or leaving it in as a placeholder.

[yzang2019]

Sounds good, if we plan to add metrics in the future, let's keep the name there

[yzang2019]

Any attempt to assign them to a standard integer variable (e.g., var x int64 = unit.ZB) will fail at compile time, this might be a bit confusing, do you think we would need to use that unit at all? Or shall we just remove them for now and add them when we really need it?

[cody-littley]

Lol, very good point. I've removed the ZB and YB constants.

[blindchaser]

• fixedPool and elasticPool both return an error for nil tasks but adHocPool launches go task() directly. consider adding a nil check.
• the passed in context cancellation is ignored

[cody-littley]

ixedPool and elasticPool both return an error for nil tasks but adHocPool launches go task() directly. consider adding a nil check.

check added

the passed in context cancellation is ignored

This now checks to see if the context is done before invoking