0.2.79 - Slow api fixes

server/internal/store/tracing.go

@@ -0,0 +1,39 @@
+package store
+
+import (
+	"context"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+
+	"github.com/ponzischeme89/memby/server/internal/timing"
+)
+
+// queryTracer attributes Postgres time to the request that asked for it.
+//
+// pgx's tracer interface is the only place every query in the gateway passes through —
+// there are several hundred call sites across internal/store and instrumenting them by
+// hand would guarantee the one that matters is the one nobody wrapped. The SQL itself
+// is deliberately not recorded: a breakdown is read beside a request line in the admin
+// console, and a query text there would put table and column names in front of anybody
+// who can open the log.
+type queryTracer struct{}
+
+type queryStartKey struct{}
+
+func (queryTracer) TraceQueryStart(
+	ctx context.Context, _ *pgx.Conn, _ pgx.TraceQueryStartData,
+) context.Context {
+	if timing.From(ctx) == nil {
+		return ctx
+	}
+	return context.WithValue(ctx, queryStartKey{}, time.Now())
+}
+
+func (queryTracer) TraceQueryEnd(ctx context.Context, _ *pgx.Conn, _ pgx.TraceQueryEndData) {
+	began, ok := ctx.Value(queryStartKey{}).(time.Time)
+	if !ok {
+		return
+	}
+	timing.Record(ctx, timing.StageDB, time.Since(began))
+}