database/sql: reordering fields to reduce struct sizes

src/database/sql/sql.go

@@ -551,9 +551,9 @@ type driverConn struct {
 
 	// guarded by db.mu
 	inUse      bool
+	dbmuClosed bool      // same as closed, but guarded by db.mu, for removeClosedStmtLocked
 	returnedAt time.Time // Time the connection was created or returned.
 	onPut      []func()  // code (with db.mu held) run when conn is next returned
-	dbmuClosed bool      // same as closed, but guarded by db.mu, for removeClosedStmtLocked
 }
 
 func (dc *driverConn) releaseConn(err error) {
@@ -2923,19 +2923,8 @@ type Rows struct {
 	//
 	// closemu guards lasterr and closed.
 	closemu sync.RWMutex
-	closed  bool
 	lasterr error // non-nil only if closed is true
-
-	// lastcols is only used in Scan, Next, and NextResultSet which are expected
-	// not to be called concurrently.
-	lastcols []driver.Value
-
-	// raw is a buffer for RawBytes that persists between Scan calls.
-	// This is used when the driver returns a mismatched type that requires
-	// a cloning allocation. For example, if the driver returns a *string and
-	// the user is scanning into a *RawBytes, we need to copy the string.
-	// The raw buffer here lets us reuse the memory for that copy across Scan calls.
-	raw []byte
+	closed  bool
 
 	// closemuScanHold is whether the previous call to Scan kept closemu RLock'ed
 	// without unlocking it. It does that when the user passes a *RawBytes scan
@@ -2951,6 +2940,17 @@ type Rows struct {
 	// returning. It's only used by Next and Err which are
 	// expected not to be called concurrently.
 	hitEOF bool
+
+	// lastcols is only used in Scan, Next, and NextResultSet which are expected
+	// not to be called concurrently.
+	lastcols []driver.Value
+
+	// raw is a buffer for RawBytes that persists between Scan calls.
+	// This is used when the driver returns a mismatched type that requires
+	// a cloning allocation. For example, if the driver returns a *string and
+	// the user is scanning into a *RawBytes, we need to copy the string.
+	// The raw buffer here lets us reuse the memory for that copy across Scan calls.
+	raw []byte
 }
 
 // lasterrOrErrLocked returns either lasterr or the provided err.