[ggevay]

With the coordinator's peek sequencing and read-then-write paths gone, the frontend_ prefix no longer tells two implementations apart in these names. Renames only, no behavior change.

Best reviewed commit by commit:

1. Module. frontend_peek.rs becomes peek_sequencing.rs. Pure rename (git show -M).
2. Peek sequencing names. try_frontend_peek(_inner) becomes try_peek(_inner), frontend_determine_timestamp becomes determine_timestamp, Command::RegisterFrontendPeek/UnregisterFrontendPeek and their handlers become RegisterPeek/UnregisterPeek and handle_(un)register_peek, and the MCP test case for SELECT becomes select_not_vulnerable. The debug span and the debug logs that name these functions follow.
3. Peek metric label values.
   • mz_slow_message_handling{message_kind}: register-frontend-peek and unregister-frontend-peek become register-peek and unregister-peek.
   • mz_catalog_snapshot_seconds{context} and mz_catalog_snapshot_cache{context}: try_frontend_peek becomes try_peek.
   • No Grafana alert rule or shared dashboard selects these values by name. Panels that group by the label (environmentd health, Release health) show the new series name from this release on.
4. Read-then-write names. try_frontend_read_then_write(_with_cancel), frontend_read_then_write_applies, PeekClient::frontend_read_then_write (now session_read_then_write, next to background_read_then_write), FrontendWriteAttemptState, FrontendWriteCancellation, the try_frontend_read_then_write catalog-snapshot context and the tests named after them drop the prefix. The module keeps its name, next to coord::read_then_write.

@aljoscha, commit 4 renames your read-then-write code. Shout if you'd rather keep any of these names. Panel 110 of your "Frontend read-then-write" playground dashboard selects context="try_frontend_read_then_write" and needs the new value.

"Frontend" stays where it still distinguishes something: statement logging (the coordinator keeps its own for the statements it sequences), the LaunchDarkly sync (SystemParameterFrontend*), and pgwire's FrontendMessage.

🤖 Generated with Claude Code

[aljoscha]

Looks good, also okay with the renames to "my" code. Could you also do the follow-up then, please of updating my dashboard once this is in?

On the name peek_sequencing. Maybe we can find sth better. Sequencing used to be the specific thing that the coordinator does for plans. Ahh, on second though might be okay, we still "sequence" it, but just in the frontend. Leave as you want, sorry for the ramble... 😅

[ggevay]

Thanks! I'll update the panel on your dashboard once the stack is in. Keeping peek_sequencing.