Apr 9, 2026 · Accepted

Experiment 032: Row Map Facade Overrides

Date: 2026-04-09

Status: Accepted

Problem

resqlite's transport/result shape is strong: one shared RowSchema, one flat

values list, and lazy Row wrappers. But Row itself uses MapMixin, and

many of the default MapBase operations are intentionally skeletal rather than

optimal.

That means Row can be excellent at transport and still pay avoidable cost on

the main isolate for common Map-style operations like:

• containsKey
• forEach
• entries
• values
• Map.from(row)

Hypothesis

Keep the transport shape exactly as-is, but override the hot Map members on

Row so they operate directly on the flat values list instead of going through

generic MapMixin behavior.

This should improve main-isolate row consumption without hurting the isolate

transfer story that makes ResultSet fast in the first place.

What We Built

In lib/src/row.dart:

• override containsKey
• override containsValue
• override length, isEmpty, isNotEmpty
• override values
• override entries
• override forEach
• add lightweight custom iterables for values and entries

Importantly:

• ResultSet shape did not change
• RowSchema shape did not change
• row.keys still uses schema names directly

Benchmark

Added targeted microbenchmark:

• benchmark/experiments/row_map_facade.dart

This compares resqliteRow against a LinkedHashMap built from the same row

data for the operations we care about.

Before

After

Result

This is a clear improvement.

The transport shape already seemed right. The problem really was the

main-isolate MapMixin facade.

What improved materially:

• containsKey: much closer to LinkedHashMap
• forEach: now slightly faster than LinkedHashMap
• entries: now faster than LinkedHashMap
• values: major improvement, now faster than LinkedHashMap in the latest run
• Map.from(row): now slightly faster than Map.from(map)

What did not change much:

• direct hot row['field'] lookups
• the existing keys + lookup path, which was already good

Why Accepted

This keeps the best part of the current design — the result transport shape —

while making Row behave much more like a performant Map on the main

isolate.