98555ca499
Adds db/pglite, a bridge that runs the PGlite WASI build of PostgreSQL 17.5 inside the Navidrome process with wazero and exposes it to database/sql through pgx over the real wire protocol. Selected with DbPath = "pglite://<dir>". The bridge handles what the WASI build cannot do on its own: it emulates dup2 onto stdin (wazero refuses fd_renumber on preopens), replays ParameterStatus for connections after the first, synthesizes a missing ReadyForQuery after an error, recovers from the trap every PG ERROR raises, and passes wire bytes through shared wasm memory instead of files (round-trip floor 377 µs to 39 µs). Several connections are accepted and serialized onto the single backend, holding the session across a whole transaction and a whole handshake; a client that disconnects mid-transaction gets a ROLLBACK. db.go opens the pglite:// scheme, skips the SQLite-only migrations, and can apply a translated schema from ND_PGLITE_SCHEMA. The shared count() helper now adds its ORDER BY only for SQLite, since Postgres rejects it next to count(distinct ...). The wasm archive is not committed. The README explains how to build it and lists the limits found: one session, one process (DevExternalScanner must be off), shared session state, simple protocol only. |
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|---|---|---|
| .. | ||
| concurrency_test.go | ||
| pglite.go | ||
| pglite_suite_test.go | ||
| pglite_test.go | ||
| proto_test.go | ||
| README.md | ||
| setup.go | ||
| stdin.go | ||
db/pglite — spike: PostgreSQL embedded in the Navidrome binary
Runs the PGlite WASI build of PostgreSQL 17.5 inside the process with
wazero (pure Go, no CGO), and exposes it to database/sql through the real PostgreSQL wire
protocol. Enabled with DbPath = "pglite://<dir>".
This is exploratory. It is not a supported way to run Navidrome. The 131 SQLite migrations are not ported, so the
schema has to be supplied by hand (ND_PGLITE_SCHEMA), and several queries Navidrome generates are SQLite-only.
How it fits together
Navidrome → database/sql → pgx → unix socket → bridge → wasm memory → PostgreSQL (wasm)
The bridge speaks no SQL. It copies wire-protocol bytes, and only inspects message framing, the handshake, and the
ReadyForQuery status byte. PGlite.OpenDB() swaps the unix socket for an in-process pipe; both perform the same, so
the socket is the default because external tools can use it.
Getting the wasm binary
Not in the repository: it is a 6.7 MB archive containing a 17 MB wasm module. Build it, then point the tests at it
with ND_PGLITE_TARBALL, or drop it at tmp/pglite-wasi-O2-fix.tar.gz (the default the tests look for).
The published WASI builds are all compiled -O0; rebuilding with -O2 is worth 2 to 3x on every query and cuts
startup from 16 s to 1.8 s. The build recipe and the patches, including one C fix of our own, are in the spike notes
under tmp/pglite-build/ on the pglite-spike branch.
Connecting with psql
PGPASSWORD=x PGSSLMODE=disable psql -h /absolute/path/to/DataFolder -U postgres postgres
The exact command is logged at startup. A password is required even though PGlite skips authentication. Plain SQL
works; \dt and \d do not, because the build's session schema is pg_catalog and its system views are missing.
Known limits
- One session. PGlite is a single PostgreSQL backend. The bridge accepts several connections and serializes them, holding the session across a whole transaction and a whole handshake. Four connections perform exactly like one.
- One process. Set
DevExternalScanner = false. Navidrome otherwise scans in a child process, which would open a second PGlite on the same data directory and corrupt it. - Session state is shared.
SET, temp tables and the like leak between clients. - Simple protocol only. The WASI build mishandles extended-protocol portals, so the DSN pins
default_query_exec_mode=simple_protocol. - No
COPY FROM STDIN. The tick loop cannot suspend to wait for the data rows.
Environment switches
| variable | effect |
|---|---|
ND_PGLITE_TARBALL |
path to the wasm archive (tests) |
ND_PGLITE_SCHEMA |
apply a schema file after connecting, tolerating failures |
ND_PGLITE_TRACE |
log wire traffic and per-tick timings |
ND_PGLITE_NOCMA |
force the file transport instead of shared memory |