diff options
| -rw-r--r-- | db.go | 24 | ||||
| -rw-r--r-- | tx.go | 6 |
2 files changed, 20 insertions, 10 deletions
@@ -33,6 +33,7 @@ const IgnoreNoSync = runtime.GOOS == "openbsd" const ( DefaultMaxBatchSize int = 1000 DefaultMaxBatchDelay = 10 * time.Millisecond + DefaultAllocSize = 16 * 1024 * 1024 ) // DB represents a collection of buckets persisted to a file on disk. @@ -85,6 +86,11 @@ type DB struct { // Do not change concurrently with calls to Batch. MaxBatchDelay time.Duration + // AllocSize is the amount of space allocated when the database + // needs to create new pages. This is done to amortize the cost + // of truncate() and fsync() when growing the data file. + AllocSize int + path string file *os.File dataref []byte // mmap'ed readonly, write throws SEGV @@ -148,6 +154,7 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) { // Set default values for later DB operations. db.MaxBatchSize = DefaultMaxBatchSize db.MaxBatchDelay = DefaultMaxBatchDelay + db.AllocSize = DefaultAllocSize flag := os.O_RDWR if options.ReadOnly { @@ -799,20 +806,19 @@ func (db *DB) allocate(count int) (*page, error) { return p, nil } -// growSize grows the size of the database to the given sz. -func (db *DB) growSize(sz int) error { +// grow grows the size of the database to the given sz. +func (db *DB) grow(sz int) error { + // Ignore if the new size is less than available file size. if sz <= db.filesz { return nil } - // over allocate 16MB to avoid calling Truncate aggressively - // for efficiency - overAllocation := 16 * 1024 * 1024 - sz = sz + overAllocation - - // do not over allocate - if sz > db.datasz { + // If the data is smaller than the alloc size then only allocate what's needed. + // Once it goes over the allocation size then allocate in chunks. + if db.datasz < db.AllocSize { sz = db.datasz + } else { + sz += db.AllocSize } // Truncate and fsync to ensure file size metadata is flushed. @@ -184,8 +184,12 @@ func (tx *Tx) Commit() error { } tx.meta.freelist = p.id + // If the high water mark has moved up then attempt to grow the database. if tx.meta.pgid > opgid { - tx.db.growSize(int(tx.meta.pgid+1) * tx.db.pageSize) + if err := tx.db.grow(int(tx.meta.pgid+1) * tx.db.pageSize); err != nil { + tx.rollback() + return err + } } // Write dirty pages to disk. |