diff options
Diffstat (limited to 'db.go')
| -rw-r--r-- | db.go | 57 |
1 files changed, 57 insertions, 0 deletions
@@ -523,6 +523,63 @@ func (db *DB) Stat() (*Stat, error) { return s, nil } +// Check performs several consistency checks on the database. +// An error is returned if any inconsistency is found. +func (db *DB) Check() error { + return db.Update(func(tx *Tx) error { + var errors ErrorList + + // Track every reachable page. + reachable := make(map[pgid]*page) + reachable[0] = tx.page(0) // meta0 + reachable[1] = tx.page(1) // meta1 + reachable[tx.meta.buckets] = tx.page(tx.meta.buckets) + reachable[tx.meta.freelist] = tx.page(tx.meta.freelist) + + // Check each reachable page within each bucket. + for _, bucket := range tx.Buckets() { + // warnf("[bucket] %s", bucket.name) + tx.forEachPage(bucket.root, 0, func(p *page, _ int) { + // Ensure each page is only referenced once. + for i := pgid(0); i <= pgid(p.overflow); i++ { + var id = p.id + i + if _, ok := reachable[id]; ok { + errors = append(errors, fmt.Errorf("page %d: multiple references", int(id))) + } + reachable[id] = p + } + + // Retrieve page info. + info, err := tx.Page(int(p.id)) + // warnf("[page] %d + %d (%s)", p.id, p.overflow, info.Type) + if err != nil { + errors = append(errors, err) + } else if info == nil { + errors = append(errors, fmt.Errorf("page %d: out of bounds: %d", int(p.id), int(tx.meta.pgid))) + } else if info.Type != "branch" && info.Type != "leaf" { + errors = append(errors, fmt.Errorf("page %d: invalid type: %s", int(p.id), info.Type)) + } + }) + } + + // Ensure all pages below high water mark are either reachable or freed. + for i := pgid(0); i < tx.meta.pgid; i++ { + _, isReachable := reachable[i] + if !isReachable && !db.freelist.isFree(i) { + errors = append(errors, fmt.Errorf("page %d: unreachable unfreed", int(i))) + } + } + + // TODO(benbjohnson): Ensure that only one buckets page exists. + + if len(errors) > 0 { + return errors + } + + return nil + }) +} + // page retrieves a page reference from the mmap based on the current page size. func (db *DB) page(id pgid) *page { pos := id * pgid(db.pageSize) |