Lazily initialize _cf_KV sqlite table.

[kentonv]

This way, if a Durable Object never actually uses the KV storage interface -- only uses SQL -- we'll never create the table and can skip preparing statements for it.

This will also make it easier for the edge runtime to clean up actors that never had data.

[anonrig]

Is there a test to ensure that the db is in WAL mode?

[kentonv]

I guess not at present.

Technically workerd works fine in any mode, we only enable WAL because it's better.

Storage Relay Service (what we use on the edge) absolutely requires WAL mode, so all its tests would certainly blow up with out it. But it also doesn't depend on workerd setting it; it sets WAL mode itself in internal code.

[justin-mp]

Hmm, the //src/workerd/api:sql-test the test is unhappy:

workerd/server/server.c++:3791: debug: [ TEST ] main
(18:00:15) [2,869 / 2,870] Testing @@workerd//src/workerd/api:sql-test; 1s linux-sandbox
workerd/io/worker.c++:1925: info: uncaught exception; source = Uncaught (in promise); stack = AssertionError [ERR_ASSERTION]: The input did not match the regular expression /access to _cf_KV.key is prohibited/. Input:

'Error: no such table: _cf_KV: SQLITE_ERROR'

    at new AssertionError (node-internal:internal_assertionerror:419:15)
    at createAssertionError (node-internal:internal_assert:35:19)
    at validateThrownError (node-internal:internal_assert:552:15)
    at Module.throws (node-internal:internal_assert:97:13)
    at test (worker:267:10)
    at async DurableObjectExample.fetch (worker:1131:7)
workerd/io/io-context.c++:355: info: uncaught exception; exception = workerd/jsg/_virtual_includes/jsg/workerd/jsg/value.h:1355: failed: jsg.Error: AssertionError: The input did not match the regular expression /access to _cf_KV.key is prohibited/. Input:

'Error: no such table: _cf_KV: SQLITE_ERROR'

Did we miss a bypass or initialization somewhere?

[kentonv]

Did we miss a bypass or initialization somewhere?

No, the test was checking for precise error text that depended on the _cf_KV table existing, but now it's lazily initialized. Fixed by adding a storage.put() before the check.