Merge pull request #16 from heyitsanthony/config-page-size

Options.PageSize

bucket_test.go

@@ -1214,7 +1214,7 @@ func TestBucket_Stats(t *testing.T) {
 		}
 
 		// Only check allocations for 4KB pages.
-		if os.Getpagesize() == 4096 {
+		if db.Info().PageSize == 4096 {
 			if stats.BranchAlloc != 4096 {
 				t.Fatalf("unexpected BranchAlloc: %d", stats.BranchAlloc)
 			} else if stats.LeafAlloc != 36864 {
@@ -1347,7 +1347,7 @@ func TestBucket_Stats_Small(t *testing.T) {
 			t.Fatalf("unexpected LeafInuse: %d", stats.LeafInuse)
 		}
 
-		if os.Getpagesize() == 4096 {
+		if db.Info().PageSize == 4096 {
 			if stats.BranchAlloc != 0 {
 				t.Fatalf("unexpected BranchAlloc: %d", stats.BranchAlloc)
 			} else if stats.LeafAlloc != 0 {
@@ -1406,7 +1406,7 @@ func TestBucket_Stats_EmptyBucket(t *testing.T) {
 			t.Fatalf("unexpected LeafInuse: %d", stats.LeafInuse)
 		}
 
-		if os.Getpagesize() == 4096 {
+		if db.Info().PageSize == 4096 {
 			if stats.BranchAlloc != 0 {
 				t.Fatalf("unexpected BranchAlloc: %d", stats.BranchAlloc)
 			} else if stats.LeafAlloc != 0 {
@@ -1508,7 +1508,7 @@ func TestBucket_Stats_Nested(t *testing.T) {
 			t.Fatalf("unexpected LeafInuse: %d", stats.LeafInuse)
 		}
 
-		if os.Getpagesize() == 4096 {
+		if db.Info().PageSize == 4096 {
 			if stats.BranchAlloc != 0 {
 				t.Fatalf("unexpected BranchAlloc: %d", stats.BranchAlloc)
 			} else if stats.LeafAlloc != 8192 {
@@ -1581,7 +1581,7 @@ func TestBucket_Stats_Large(t *testing.T) {
 			t.Fatalf("unexpected LeafInuse: %d", stats.LeafInuse)
 		}
 
-		if os.Getpagesize() == 4096 {
+		if db.Info().PageSize == 4096 {
 			if stats.BranchAlloc != 53248 {
 				t.Fatalf("unexpected BranchAlloc: %d", stats.BranchAlloc)
 			} else if stats.LeafAlloc != 4898816 {

db.go

@@ -199,6 +199,11 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) {
 	// Default values for test hooks
 	db.ops.writeAt = db.file.WriteAt
 
+	if db.pageSize = options.PageSize; db.pageSize == 0 {
+		// Set the default page size to the OS page size.
+		db.pageSize = defaultPageSize
+	}
+
 	// Initialize the database if it doesn't exist.
 	if info, err := db.file.Stat(); err != nil {
 		return nil, err
@@ -210,20 +215,21 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) {
 	} else {
 		// Read the first meta page to determine the page size.
 		var buf [0x1000]byte
-		if _, err := db.file.ReadAt(buf[:], 0); err == nil {
-			m := db.pageInBuffer(buf[:], 0).meta()
-			if err := m.validate(); err != nil {
-				// If we can't read the page size, we can assume it's the same
-				// as the OS -- since that's how the page size was chosen in the
-				// first place.
-				//
-				// If the first page is invalid and this OS uses a different
-				// page size than what the database was created with then we
-				// are out of luck and cannot access the database.
-				db.pageSize = os.Getpagesize()
-			} else {
+		// If we can't read the page size, but can read a page, assume
+		// it's the same as the OS or one given -- since that's how the
+		// page size was chosen in the first place.
+		//
+		// If the first page is invalid and this OS uses a different
+		// page size than what the database was created with then we
+		// are out of luck and cannot access the database.
+		//
+		// TODO: scan for next page
+		if bw, err := db.file.ReadAt(buf[:], 0); err == nil && bw == len(buf) {
+			if m := db.pageInBuffer(buf[:], 0).meta(); m.validate() == nil {
 				db.pageSize = int(m.pageSize)
 			}
+		} else {
+			return nil, ErrInvalid
 		}
 	}
 
@@ -373,9 +379,6 @@ func (db *DB) mmapSize(size int) (int, error) {
 
 // init creates a new database file and initializes its meta pages.
 func (db *DB) init() error {
-	// Set the page size to the OS page size.
-	db.pageSize = os.Getpagesize()
-
 	// Create two meta pages on a buffer.
 	buf := make([]byte, db.pageSize*4)
 	for i := 0; i < 2; i++ {
@@ -1002,6 +1005,9 @@ type Options struct {
 	// If initialMmapSize is smaller than the previous database size,
 	// it takes no effect.
 	InitialMmapSize int
+
+	// PageSize overrides the default OS page size.
+	PageSize int
 }
 
 // DefaultOptions represent the options used if nil options are passed into Open().

db_test.go

@@ -339,12 +339,13 @@ func TestOpen_FileTooSmall(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	pageSize := int64(db.Info().PageSize)
 	if err := db.Close(); err != nil {
 		t.Fatal(err)
 	}
 
 	// corrupt the database
-	if err := os.Truncate(path, int64(os.Getpagesize())); err != nil {
+	if err := os.Truncate(path, pageSize); err != nil {
 		t.Fatal(err)
 	}
 
@@ -414,6 +415,22 @@ func TestDB_Open_InitialMmapSize(t *testing.T) {
 	}
 }
 
+// TestOpen_BigPage checks the database uses bigger pages when
+// changing PageSize.
+func TestOpen_BigPage(t *testing.T) {
+	pageSize := os.Getpagesize()
+
+	db1 := MustOpenWithOption(&bolt.Options{PageSize: pageSize * 2})
+	defer db1.MustClose()
+
+	db2 := MustOpenWithOption(&bolt.Options{PageSize: pageSize * 4})
+	defer db2.MustClose()
+
+	if db1sz, db2sz := fileSize(db1.f), fileSize(db2.f); db1sz >= db2sz {
+		t.Errorf("expected %d < %d", db1sz, db2sz)
+	}
+}
+
 // TestOpen_RecoverFreeList tests opening the DB with free-list
 // write-out after no free list sync will recover the free list
 // and write it out.