Write-Ahead Logging is both much more performant in general, and more suited to our particular access patterns.

With a simple throughput performance test, it improves performance by a factor of 5-20x depending on the sync flag.

(*) previous setting
(**) new setting

I went with a conservative new setting of wal+full sync, which is both 5x more performant, and more secure than what we had before.

In WAL mode when synchronous is NORMAL (1), the WAL file is synchronized before each checkpoint and the database file is synchronized after each completed checkpoint and the WAL file header is synchronized when a WAL file begins to be reused after a checkpoint, but no sync operations occur during most transactions. With synchronous=FULL in WAL mode, an additional sync operation of the WAL file happens after each transaction commit. The extra WAL sync following each transaction help ensure that transactions are durable across a power loss. Transactions are consistent with or without the extra syncs provided by synchronous=FULL. If durability is not a concern, then synchronous=NORMAL is normally all one needs in WAL mode.

@joostjager I couldn't help but notice that despite using a different test setting, I get exactly the same result as you with the baseline, on my laptop. Is there any chance you could re-run your test with this branch?