fix: lower amount of cached timezones for deployment daus (#11196)

Updates https://github.com/coder/customers/issues/384

This should help alleviate some pressure, but doesn't really fix the
root cause. See above issue for more details.

coderd/httpmw/workspaceagentparam_test.go

@@ -6,12 +6,12 @@ import (
 	"net/http/httptest"
 	"testing"
 
-	"cdr.dev/slog"
 	"github.com/go-chi/chi/v5"
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/xerrors"
 
+	"cdr.dev/slog"
 	"github.com/coder/coder/v2/coderd/coderdtest"
 	"github.com/coder/coder/v2/coderd/database"
 	"github.com/coder/coder/v2/coderd/database/dbauthz"

coderd/metricscache/metricscache.go

@@ -26,8 +26,14 @@ import (
 // Any non-listed timezone offsets will need to use the closest supported one.
 var deploymentTimezoneOffsets = []int{
 	0, // UTC - is listed first intentionally.
-	-12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1,
-	1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
+	// Shortened list of 4 timezones that should encompass *most* users. Caching
+	// all 25 timezones can be too computationally expensive for large
+	// deployments. This is a stop-gap until more robust fixes can be made for
+	// the deployment DAUs query.
+	-6, 3, 6, 10,
+
+	// -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1,
+	// 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
 }
 
 // templateTimezoneOffsets are the timezones each template will use for it's DAU

coderd/metricscache/metricscache_test.go

@@ -152,11 +152,11 @@ func TestCache_TemplateUsers(t *testing.T) {
 		},
 		{
 			name:     "tzOffset",
-			tzOffset: 1,
+			tzOffset: 3,
 			args: args{
 				rows: []database.InsertWorkspaceAgentStatParams{
-					statRow(zebra, dateH(2022, 1, 2, 1)),
-					statRow(tiger, dateH(2022, 1, 2, 1)),
+					statRow(zebra, dateH(2022, 1, 2, 3)),
+					statRow(tiger, dateH(2022, 1, 2, 3)),
 					// With offset these should be in the previous day
 					statRow(zebra, dateH(2022, 1, 2, 0)),
 					statRow(tiger, dateH(2022, 1, 2, 0)),

codersdk/deployment.go

@@ -1630,7 +1630,7 @@ when required by your organization's security policy.`,
 			Flag:        "metrics-cache-refresh-interval",
 			Env:         "CODER_METRICS_CACHE_REFRESH_INTERVAL",
 			Hidden:      true,
-			Default:     time.Hour.String(),
+			Default:     (4 * time.Hour).String(),
 			Value:       &c.MetricsCacheRefreshInterval,
 			Annotations: clibase.Annotations{}.Mark(annotationFormatDuration, "true"),
 		},