diff options
Diffstat (limited to 'db.go')
| -rw-r--r-- | db.go | 51 |
1 files changed, 51 insertions, 0 deletions
@@ -506,6 +506,34 @@ func (db *DB) CopyFile(path string, mode os.FileMode) error { return db.Copy(f) } +// Stat retrieves stats on the database and its page usage. +// Returns an error if the database is not open. +func (db *DB) Stat() (*Stat, error) { + // Obtain meta & mmap locks. + db.metalock.Lock() + db.mmaplock.RLock() + + var s = &Stat{ + MmapSize: len(db.data), + TransactionCount: len(db.transactions), + } + + // Release locks. + db.mmaplock.RUnlock() + db.metalock.Unlock() + + err := db.Do(func(t *RWTransaction) error { + s.PageCount = int(t.meta.pgid) + s.FreePageCount = len(db.freelist.all()) + s.PageSize = db.pageSize + return nil + }) + if err != nil { + return nil, err + } + return s, nil +} + // page retrieves a page reference from the mmap based on the current page size. func (db *DB) page(id pgid) *page { return (*page)(unsafe.Pointer(&db.data[id*pgid(db.pageSize)])) @@ -550,3 +578,26 @@ func (db *DB) allocate(count int) (*page, error) { return p, nil } + +// Stat represents stats on the database such as free pages and sizes. +type Stat struct { + // PageCount is the total number of allocated pages. This is a high water + // mark in the database that represents how many pages have actually been + // used. This will be smaller than the MmapSize / PageSize. + PageCount int + + // FreePageCount is the total number of pages which have been previously + // allocated but are no longer used. + FreePageCount int + + // PageSize is the size, in bytes, of individual database pages. + PageSize int + + // MmapSize is the mmap-allocated size of the data file. When the data file + // grows beyond this size, the database will obtain a lock on the mmap and + // resize it. + MmapSize int + + // TransactionCount is the total number of reader transactions. + TransactionCount int +} |