Cherry-picked from #4404
Better default for confirmed reads (which are the default since #4390).

Cherry-picked from #4404
Better default for confirmed reads (which are the default since #4390).

Instead of periodic flush + sync, the simplified commitlog buffering
makes it easy to just pop a batch of transaction from the queue, commit
them, and then flush + sync after each batch.

This may lead to an overall higher number of fsyncs on the system, but
also adapts to the tx throughput of the individual database (up to the
batch size).

After taking some measurements, we may want to make the batch size
configurable at runtime.

Depends-on: #4404

# Description of Changes

This does 3 things to the keynote-2 benchmark:
- it changes the default alpha to 1.5, which we actually tested the
other services with
- it turns on confirmed reads (not the default for < 2.0)
- it removes warmup

This was tested on
#4404 to have no impact
on the TPS throughput of spacetimedb.
**This PR shouldn't be merged before #4404 has.**

# API and ABI breaking changes

None

# Expected complexity level and risk

1

# Testing

This tweaks a bench test.

# Description of Changes

This does 3 things to the keynote-2 benchmark:
- it changes the default alpha to 1.5, which we actually tested the
other services with
- it turns on confirmed reads (not the default for < 2.0)
- it removes warmup

This was tested on
#4404 to have no impact
on the TPS throughput of spacetimedb.
**This PR shouldn't be merged before #4404 has.**

# API and ABI breaking changes

None

# Expected complexity level and risk

1

# Testing

This tweaks a bench test.

Re-open #4140 (reverted in #4292).


The original patch was merged a bit too eagerly.
It should go in _after_ 2.0 is released with some confidence.

…r triggering

Two fixes:

1. Sync query methods (query_as_of_bsatn, query_as_of_pk_bsatn,
   query_time_series_bsatn, query_time_series_pk_bsatn) now detect
   missing/repairing segments and trigger repair via fire-and-forget
   spawns on the temporal runtime. Previously these methods had no
   health checks, so enabling temporal on existing databases would
   return "No data found" for AS OF queries via SQL without ever
   triggering repair. ALL BETWEEN worked because its async path
   had full health checks.

2. Grid alignment checks in build_ops.rs moved inside per-transaction
   loops for future-proofing when callers start batching multiple
   transactions per commit (upstream PR clockworklabs#4404 removed the n=1 limit).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>