perf(backend): optimize database query for deployment with latest sta…

…tus (#473)

Signed-off-by: Jakob Steiner <[email protected]>

cmd/hub/generate/status/generate.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"context"
+	"time"
+
+	internalctx "github.com/glasskube/distr/internal/context"
+	"github.com/glasskube/distr/internal/db"
+	"github.com/glasskube/distr/internal/svc"
+	"github.com/glasskube/distr/internal/types"
+	"github.com/glasskube/distr/internal/util"
+)
+
+func main() {
+	ctx := context.Background()
+	registry := util.Require(svc.NewDefault(ctx))
+	defer func() { _ = registry.Shutdown() }()
+	ctx = internalctx.WithDb(ctx, registry.GetDbPool())
+
+	revisionID := "68297e49-b17b-4d32-8111-f8ee678f73da"
+	statusCount := 500000
+	statusInterval := 5 * time.Second
+
+	now := time.Now().UTC()
+	createdAt := now.Add(time.Duration(statusCount) * -statusInterval)
+	var ds []types.DeploymentRevisionStatus
+	for createdAt.Before(now) {
+		ds = append(ds, types.DeploymentRevisionStatus{CreatedAt: createdAt, Message: "demo status"})
+		createdAt = createdAt.Add(statusInterval)
+	}
+	util.Must(db.BulkCreateDeploymentRevisionStatusWithCreatedAt(ctx, revisionID, ds))
+}

internal/db/deployments.go

@@ -83,9 +83,10 @@ func GetLatestDeploymentForDeploymentTarget(ctx context.Context, deploymentTarge
 				JOIN ApplicationVersion av ON dr.application_version_id = av.id
 				JOIN Application a ON av.application_id = a.id
 				LEFT JOIN (
-					SELECT deployment_revision_id, max(created_at) AS max_created_at
-					FROM DeploymentRevisionStatus
-					GROUP BY deployment_revision_id
+					SELECT
+						dr1.id AS deployment_revision_id,
+						(SELECT max(created_at) FROM DeploymentRevisionStatus WHERE deployment_revision_id = dr1.id) AS max_created_at
+					FROM DeploymentRevision dr1
 				) status_max ON dr.id = status_max.deployment_revision_id
 				LEFT JOIN DeploymentRevisionStatus drs
 					ON dr.id = drs.deployment_revision_id AND drs.created_at = status_max.max_created_at

internal/migrations/sql/14_deployment_revision_created_at_index.down.sql

@@ -0,0 +1 @@
+DROP INDEX DeploymentRevisionStatus_created_at;

internal/migrations/sql/14_deployment_revision_created_at_index.up.sql

@@ -0,0 +1 @@
+CREATE INDEX DeploymentRevisionStatus_created_at ON DeploymentRevisionStatus (deployment_revision_id, created_at DESC);