diff --git a/sa/database.go b/sa/database.go
index 7078ac872..19f8f4498 100644
--- a/sa/database.go
+++ b/sa/database.go
@@ -223,11 +223,12 @@ func adjustMySQLConfig(conf *mysql.Config) error {
 	// `?max_statement_time=2`. A zero value in the DSN means these won't be
 	// sent on new connections.
 	if conf.ReadTimeout != 0 {
-		// In MariaDB, max_statement_time and long_query_time are both seconds.
+		// In MariaDB, max_statement_time and long_query_time are both seconds,
+		// but can have up to microsecond granularity.
 		// Note: in MySQL (which we don't use), max_statement_time is millis.
 		readTimeout := conf.ReadTimeout.Seconds()
-		setDefault("max_statement_time", fmt.Sprintf("%g", readTimeout*0.95))
-		setDefault("long_query_time", fmt.Sprintf("%g", readTimeout*0.80))
+		setDefault("max_statement_time", fmt.Sprintf("%.6f", readTimeout*0.95))
+		setDefault("long_query_time", fmt.Sprintf("%.6f", readTimeout*0.80))
 	}
 
 	omitZero("max_statement_time")
diff --git a/sa/database_test.go b/sa/database_test.go
index 400e02c90..1585c6d89 100644
--- a/sa/database_test.go
+++ b/sa/database_test.go
@@ -108,7 +108,7 @@ func TestDbSettings(t *testing.T) {
 // TODO: Change this to test `newDbMapFromMySQLConfig` instead?
 func TestNewDbMap(t *testing.T) {
 	const mysqlConnectURL = "policy:password@tcp(boulder-proxysql:6033)/boulder_policy_integration?readTimeout=800ms&writeTimeout=800ms"
-	const expected = "policy:password@tcp(boulder-proxysql:6033)/boulder_policy_integration?clientFoundRows=true&parseTime=true&readTimeout=800ms&writeTimeout=800ms&long_query_time=0.6400000000000001&max_statement_time=0.76&sql_mode=%27STRICT_ALL_TABLES%27"
+	const expected = "policy:password@tcp(boulder-proxysql:6033)/boulder_policy_integration?clientFoundRows=true&parseTime=true&readTimeout=800ms&writeTimeout=800ms&long_query_time=0.640000&max_statement_time=0.760000&sql_mode=%27STRICT_ALL_TABLES%27"
 	oldSQLOpen := sqlOpen
 	defer func() {
 		sqlOpen = oldSQLOpen
@@ -199,8 +199,8 @@ func TestAdjustMySQLConfig(t *testing.T) {
 	test.AssertNotError(t, err, "unexpected err setting server variables")
 	test.AssertDeepEquals(t, conf.Params, map[string]string{
 		"sql_mode":           "'STRICT_ALL_TABLES'",
-		"max_statement_time": "95",
-		"long_query_time":    "80",
+		"max_statement_time": "95.000000",
+		"long_query_time":    "80.000000",
 	})
 
 	conf = &mysql.Config{
@@ -213,7 +213,7 @@ func TestAdjustMySQLConfig(t *testing.T) {
 	test.AssertNotError(t, err, "unexpected err setting server variables")
 	test.AssertDeepEquals(t, conf.Params, map[string]string{
 		"sql_mode":        "'STRICT_ALL_TABLES'",
-		"long_query_time": "80",
+		"long_query_time": "80.000000",
 	})
 
 	conf = &mysql.Config{