diff --git a/db.go b/db.go index 0f1e1bc..5d48709 100644 --- a/db.go +++ b/db.go @@ -36,6 +36,9 @@ const ( DefaultAllocSize = 16 * 1024 * 1024 ) +// default page size for db is set to the OS page size. +var defaultPageSize = os.Getpagesize() + // DB represents a collection of buckets persisted to a file on disk. // All data access is performed through transactions which can be obtained through the DB. // All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called. @@ -320,7 +323,7 @@ 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() + db.pageSize = defaultPageSize // Create two meta pages on a buffer. buf := make([]byte, db.pageSize*4) @@ -779,10 +782,21 @@ func (db *DB) meta() *meta { return db.meta1 } +var pagePool = sync.Pool{ + New: func() interface{} { + return make([]byte, defaultPageSize) + }, +} + // allocate returns a contiguous block of memory starting at a given page. func (db *DB) allocate(count int) (*page, error) { // Allocate a temporary buffer for the page. - buf := make([]byte, count*db.pageSize) + var buf []byte + if count == 1 && db.pageSize == defaultPageSize { + buf = pagePool.Get().([]byte) + } else { + buf = make([]byte, count*db.pageSize) + } p := (*page)(unsafe.Pointer(&buf[0])) p.overflow = uint32(count - 1) diff --git a/tx.go b/tx.go index e74d2ca..09a39fb 100644 --- a/tx.go +++ b/tx.go @@ -441,6 +441,8 @@ func (tx *Tx) write() error { for _, p := range tx.pages { pages = append(pages, p) } + // Clear out page cache early. + tx.pages = make(map[pgid]*page) sort.Sort(pages) // Write pages to disk in order. @@ -485,8 +487,18 @@ func (tx *Tx) write() error { } } - // Clear out page cache. - tx.pages = make(map[pgid]*page) + // put small pages back to sync.Pool + for _, p := range pages { + if int(p.overflow) != 0 || tx.db.pageSize != defaultPageSize { + continue + } + buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:defaultPageSize] + // See https://go.googlesource.com/go/+/f03c9202c43e0abb130669852082117ca50aa9b1 + for i := range buf { + buf[i] = 0 + } + pagePool.Put(buf) + } return nil }