diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go')
| -rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go index b8f7e7d..21d1e51 100644 --- a/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go +++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go @@ -69,6 +69,13 @@ func (tr *Transaction) Has(key []byte, ro *opt.ReadOptions) (bool, error) { // DB. And a nil Range.Limit is treated as a key after all keys in // the DB. // +// The returned iterator has locks on its own resources, so it can live beyond +// the lifetime of the transaction who creates them. +// +// WARNING: Any slice returned by interator (e.g. slice returned by calling +// Iterator.Key() or Iterator.Key() methods), its content should not be modified +// unless noted otherwise. +// // The iterator must be released after use, by calling Release method. // // Also read Iterator documentation of the leveldb/iterator package. @@ -205,7 +212,7 @@ func (tr *Transaction) Commit() error { tr.stats.startTimer() var cerr error for retry := 0; retry < 3; retry++ { - cerr = tr.db.s.commit(&tr.rec) + cerr = tr.db.s.commit(&tr.rec, false) if cerr != nil { tr.db.logf("transaction@commit error R·%d %q", retry, cerr) select { @@ -248,13 +255,14 @@ func (tr *Transaction) discard() { // Discard transaction. for _, t := range tr.tables { tr.db.logf("transaction@discard @%d", t.fd.Num) - if err1 := tr.db.s.stor.Remove(t.fd); err1 == nil { - tr.db.s.reuseFileNum(t.fd.Num) - } + // Iterator may still use the table, so we use tOps.remove here. + tr.db.s.tops.remove(t.fd) } } // Discard discards the transaction. +// This method is noop if transaction is already closed (either committed or +// discarded) // // Other methods should not be called after transaction has been discarded. func (tr *Transaction) Discard() { @@ -278,8 +286,10 @@ func (db *DB) waitCompaction() error { // until in-flight transaction is committed or discarded. // The returned transaction handle is safe for concurrent use. // -// Transaction is expensive and can overwhelm compaction, especially if +// Transaction is very expensive and can overwhelm compaction, especially if // transaction size is small. Use with caution. +// The rule of thumb is if you need to merge at least same amount of +// `Options.WriteBuffer` worth of data then use transaction, otherwise don't. // // The transaction must be closed once done, either by committing or discarding // the transaction. |