Function TestProfilingSettingsArePerConnection

server/profiling_test.go:225–321

TestProfilingSettingsArePerConnection reproduces the cluster-mode bug: DuckDB profiling settings are session-scoped (DuckDB rejects `SET GLOBAL` for `enable_profiling` etc.), so when the worker's evictConnFromPool discards a session's connection between sessions, the next fresh connection has no pro

(t *testing.T)

// connection has no profiling configured and the profile file stays
// untouched. ProfilingSetupSQL applied per-connection is the fix.
func TestProfilingSettingsArePerConnection(t *testing.T) {
	db, err := sql.Open("duckdb", ":memory:")
	if err != nil {
		t.Fatalf("open duckdb: %v", err)
	}
	defer func() { _ = db.Close() }()
	// Two slots so we can pin two distinct underlying connections.
	db.SetMaxOpenConns(2)
	db.SetMaxIdleConns(2)

	ctx := context.Background()
	tmpFile := t.TempDir() + "/profiling.json"
	setup := ProfilingSetupSQL(tmpFile)

	// Connection A: full setup, simulates the warmup conn that ConfigureMainDB
	// ran on. Apply the production setup statements directly so we're testing
	// the same SQL the real code path uses.
	connA, err := db.Conn(ctx)
	if err != nil {
		t.Fatalf("conn A: %v", err)
	}
	defer func() { _ = connA.Close() }()
	if _, err := connA.ExecContext(ctx, "CREATE TABLE t (x INT)"); err != nil {
		t.Fatalf("create table: %v", err)
	}
	for _, s := range setup {
		if _, err := connA.ExecContext(ctx, s); err != nil {
			t.Fatalf("connA %s: %v", s, err)
		}
	}

	// Connection B: pretend we've evicted A and the pool handed out a fresh
	// conn. Without per-session re-application, this conn has no profiling
	// settings.
	connB, err := db.Conn(ctx)
	if err != nil {
		t.Fatalf("conn B: %v", err)
	}
	defer func() { _ = connB.Close() }()

	_ = os.Remove(tmpFile)
	if _, err := connB.ExecContext(ctx, "INSERT INTO t VALUES (1)"); err != nil {
		t.Fatalf("connB pre-fix INSERT: %v", err)
	}
	if data, err := os.ReadFile(tmpFile); err == nil && len(data) > 0 {
		t.Fatalf("pre-fix sanity: fresh conn should not produce profile JSON, got %d bytes", len(data))
	}

	// Now apply the same setup to connB and re-run the INSERT — this is what
	// duckdbservice.CreateSession does via server.ApplyProfilingSettings.
	for _, s := range setup {
		if _, err := connB.ExecContext(ctx, s); err != nil {
			t.Fatalf("connB re-apply %s: %v", s, err)
		}
	}
	_ = os.Remove(tmpFile)
	if _, err := connB.ExecContext(ctx, "INSERT INTO t VALUES (2)"); err != nil {
		t.Fatalf("connB post-fix INSERT: %v", err)