perf: query data AS OF SYSTEM TIME (#5231)

Queries the data in the storage layser at the timestamp when the call hit the API layer

internal/database/cockroach/config.go

@@ -2,6 +2,7 @@ package cockroach
 
 import (
 	"database/sql"
+	"fmt"
 	"strconv"
 	"strings"
 	"time"
@@ -89,6 +90,15 @@ func (c *Config) Type() string {
 	return "cockroach"
 }
 
+func (c *Config) Timetravel(d time.Duration) string {
+	// verify that it is at least 1 micro second
+	if d < time.Microsecond {
+		d = time.Microsecond
+	}
+
+	return fmt.Sprintf(" AS OF SYSTEM TIME '-%d µs' ", d.Microseconds())
+}
+
 type User struct {
 	Username string
 	Password string

internal/database/cockroach/config_test.go

@@ -0,0 +1,61 @@
+package cockroach
+
+import (
+	"testing"
+	"time"
+)
+
+func TestConfig_Timetravel(t *testing.T) {
+	type args struct {
+		d time.Duration
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "no duration",
+			args: args{
+				d: 0,
+			},
+			want: " AS OF SYSTEM TIME '-1 µs' ",
+		},
+		{
+			name: "less than microsecond",
+			args: args{
+				d: 100 * time.Nanosecond,
+			},
+			want: " AS OF SYSTEM TIME '-1 µs' ",
+		},
+		{
+			name: "10 microseconds",
+			args: args{
+				d: 10 * time.Microsecond,
+			},
+			want: " AS OF SYSTEM TIME '-10 µs' ",
+		},
+		{
+			name: "10 milliseconds",
+			args: args{
+				d: 10 * time.Millisecond,
+			},
+			want: " AS OF SYSTEM TIME '-10000 µs' ",
+		},
+		{
+			name: "1 second",
+			args: args{
+				d: 1 * time.Second,
+			},
+			want: " AS OF SYSTEM TIME '-1000000 µs' ",
+		},
+	}
+	for _, tt := range tests {
+		c := &Config{}
+		t.Run(tt.name, func(t *testing.T) {
+			if got := c.Timetravel(tt.args.d); got != tt.want {
+				t.Errorf("Config.Timetravel() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}