From f3c0535628449e3717228f94fbdd36fc95d22760 Mon Sep 17 00:00:00 2001
From: thorfour <thor.hansen@polarsignals.com>
Date: Wed, 7 Dec 2022 11:37:11 -0600
Subject: [PATCH] querydiff: perform the profile selections concurrently

---
 go.mod                   |  2 +-
 pkg/query/columnquery.go | 30 +++++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/go.mod b/go.mod
index b5a09ca6f35..ee58c4aba03 100644
--- a/go.mod
+++ b/go.mod
@@ -45,6 +45,7 @@ require (
 	go.opentelemetry.io/otel/trace v1.11.1
 	golang.org/x/exp v0.0.0-20221204150635-6dcec336b2bb
 	golang.org/x/net v0.2.0
+	golang.org/x/sync v0.1.0
 	google.golang.org/genproto v0.0.0-20221202195650-67e5cbc046fd
 	google.golang.org/grpc v1.51.0
 	google.golang.org/protobuf v1.28.1
@@ -226,7 +227,6 @@ require (
 	golang.org/x/crypto v0.1.0 // indirect
 	golang.org/x/mod v0.6.0 // indirect
 	golang.org/x/oauth2 v0.2.0 // indirect
-	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.2.0 // indirect
 	golang.org/x/term v0.2.0 // indirect
 	golang.org/x/text v0.4.0 // indirect
diff --git a/pkg/query/columnquery.go b/pkg/query/columnquery.go
index 004cdcf61cd..2957a8e95eb 100644
--- a/pkg/query/columnquery.go
+++ b/pkg/query/columnquery.go
@@ -23,6 +23,7 @@ import (
 	"github.com/go-kit/log"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/trace"
+	"golang.org/x/sync/errgroup"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 
@@ -274,14 +275,29 @@ func (q *ColumnQueryAPI) selectDiff(ctx context.Context, d *pb.DiffProfile) (*pr
 		return nil, status.Error(codes.InvalidArgument, "requested diff mode, but did not provide parameters for diff")
 	}
 
-	base, err := q.selectProfileForDiff(ctx, d.A)
-	if err != nil {
-		return nil, fmt.Errorf("reading base profile: %w", err)
-	}
+	g, ctx := errgroup.WithContext(ctx)
+	var base *profile.Profile
+	g.Go(func() error {
+		var err error
+		base, err = q.selectProfileForDiff(ctx, d.A)
+		if err != nil {
+			return fmt.Errorf("reading base profile: %w", err)
+		}
+		return nil
+	})
 
-	compare, err := q.selectProfileForDiff(ctx, d.B)
-	if err != nil {
-		return nil, fmt.Errorf("reading compared profile: %w", err)
+	var compare *profile.Profile
+	g.Go(func() error {
+		var err error
+		compare, err = q.selectProfileForDiff(ctx, d.B)
+		if err != nil {
+			return fmt.Errorf("reading compared profile: %w", err)
+		}
+		return nil
+	})
+
+	if err := g.Wait(); err != nil {
+		return nil, err
 	}
 
 	// TODO: This is cheating a bit. This should be done with a sub-query in the columnstore.