* feat: return write_token from HTTP writes to router2
* fix: Update router2/src/dml_handlers/instrumentation.rs
Co-authored-by: Dom <dom@itsallbroken.com>
* refactor: Use WriteSummary::default more vigorously
* fix: fix typo and add links to follow on issues
Co-authored-by: Dom <dom@itsallbroken.com>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>
Changes the configuration of the router request pipeline to move schema
validation before partitioning.
This reduces the concurrency of callsm into the schema validator when a
single write is split into one or more partitions, reducing contention
and cash thrashing. It also ensures we don't bother partitioning the
writes if the request will fail.
The router is composed of several DML handlers called in sequence in
order to construct the full request handling pipeline. Prior to this
commit, each handler nested the next handler it calls internally,
producing a nested call chain that resulted metrics (added in #3764)
recording cumulative latency like this:
┌ ─
│ ┌───────────────┐
│ NS Creation │
│ └───────────────┘
│ ┌───────────────┐
│ │ │ Partitioner │
│ └───────────────┘
│ │ │
│ │
Cumulative │ │ │ ┌───────────────┐
Timings 1.5s 1s │ etc... │
│ │ │ └───────────────┘
│ │
│ │ │
│ ┌───────────────┐
│ │ │ Partitioner │
│ └───────────────┘
│ ┌───────────────┐
│ NS Creation │
│ └───────────────┘
└ ─
This meant it was hard to determine the latency of a single handler
without knowing (and subtracting the latency of) all the child handlers
it calls.
This commit replaces the intrusive nested handler call chain with an
external Chain combinator type to compose together individual handlers,
resulting in correct per-handler timings and simpler code/tests:
┌───────────────┐
│ NS Creation │
└───────────────┘
│
.5s ┌───────────────┐
└───────▶│ Partitioner │
└───────────────┘
│
1s ┌───────────────┐
└───▶│ etc... │
└───────────────┘
Andrew Lamb
Dom Dwyer
Carol (Nichols || Goulding)
Marco Neumann
Luke Bond