SQLite emphatically warns against concurrent writes. It is not designed for that.

I'm seeing these numbers on my current scratch benchmark:

- Events append to a 10M+ record table (~4+ GiB database).

- Reads are fetched from a separate computed table, which is trigger-updated from the append-only table.

- WAL-mode ON, Auto-vacuum ON

  {:dbtype "sqlite",
   :auto_vacuum "INCREMENTAL",
   :connectionTestQuery "PRAGMA journal_mode;",
   :preferredTestQuery "PRAGMA journal_mode;",
   :dataSourceProperties
   {:journal_mode "WAL",
    :limit_worker_threads 4,
    :page_size 4096,
    :busy_timeout 5000,
    :enable_load_extension true,
    :foreign_keys "ON",
    :journal_size_limit 0,
    :cache_size 15625,
    :maximumPoolSize 1,
    :synchronous "NORMAL"}},

- 1,600 sequential (in a single process) read-after-write transactions, append-only, no batching.

- With a separate writer process (sequential), and concurrently, two reader processes, I'm seeing 400+ append transactions/second (into the append-only table, no batching), and a total of 41,000 reads per second, doing `select *` on the trigger-updated table.

My schema is (deliberately) poor --- most of it is TEXT.

(edit: add clarifying text)