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author | Felix Lange <fjl@twurst.com> | 2016-10-20 20:56:34 +0800 |
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committer | Felix Lange <fjl@twurst.com> | 2016-10-20 20:56:34 +0800 |
commit | b930baa58078862d082745330038e60d0767026c (patch) | |
tree | 4584574278774fb438948dfe782e6845fab5a791 /Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go | |
parent | 66ee2dec53f9e18b4def0b0005e291fdd810f327 (diff) | |
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Godeps: update github.com/syndtr/goleveldb to 6b4daa5362
Diffstat (limited to 'Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go | 68 |
1 files changed, 52 insertions, 16 deletions
diff --git a/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go index fca88037b..b8f7e7d21 100644 --- a/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go +++ b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/db_transaction.go @@ -59,8 +59,8 @@ func (tr *Transaction) Has(key []byte, ro *opt.ReadOptions) (bool, error) { } // NewIterator returns an iterator for the latest snapshot of the transaction. -// The returned iterator is not goroutine-safe, but it is safe to use multiple -// iterators concurrently, with each in a dedicated goroutine. +// The returned iterator is not safe for concurrent use, but it is safe to use +// multiple iterators concurrently, with each in a dedicated goroutine. // It is also safe to use an iterator concurrently while writes to the // transaction. The resultant key/value pairs are guaranteed to be consistent. // @@ -167,8 +167,8 @@ func (tr *Transaction) Write(b *Batch, wo *opt.WriteOptions) error { if tr.closed { return errTransactionDone } - return b.decodeRec(func(i int, kt keyType, key, value []byte) error { - return tr.put(kt, key, value) + return b.replayInternal(func(i int, kt keyType, k, v []byte) error { + return tr.put(kt, k, v) }) } @@ -179,7 +179,8 @@ func (tr *Transaction) setDone() { <-tr.db.writeLockC } -// Commit commits the transaction. +// Commit commits the transaction. If error is not nil, then the transaction is +// not committed, it can then either be retried or discarded. // // Other methods should not be called after transaction has been committed. func (tr *Transaction) Commit() error { @@ -192,24 +193,27 @@ func (tr *Transaction) Commit() error { if tr.closed { return errTransactionDone } - defer tr.setDone() if err := tr.flush(); err != nil { - tr.discard() + // Return error, lets user decide either to retry or discard + // transaction. return err } if len(tr.tables) != 0 { // Committing transaction. tr.rec.setSeqNum(tr.seq) tr.db.compCommitLk.Lock() - defer tr.db.compCommitLk.Unlock() + tr.stats.startTimer() + var cerr error for retry := 0; retry < 3; retry++ { - if err := tr.db.s.commit(&tr.rec); err != nil { - tr.db.logf("transaction@commit error R·%d %q", retry, err) + cerr = tr.db.s.commit(&tr.rec) + if cerr != nil { + tr.db.logf("transaction@commit error R·%d %q", retry, cerr) select { case <-time.After(time.Second): - case _, _ = <-tr.db.closeC: + case <-tr.db.closeC: tr.db.logf("transaction@commit exiting") - return err + tr.db.compCommitLk.Unlock() + return cerr } } else { // Success. Set db.seq. @@ -217,9 +221,26 @@ func (tr *Transaction) Commit() error { break } } + tr.stats.stopTimer() + if cerr != nil { + // Return error, lets user decide either to retry or discard + // transaction. + return cerr + } + + // Update compaction stats. This is safe as long as we hold compCommitLk. + tr.db.compStats.addStat(0, &tr.stats) + // Trigger table auto-compaction. tr.db.compTrigger(tr.db.tcompCmdC) + tr.db.compCommitLk.Unlock() + + // Additionally, wait compaction when certain threshold reached. + // Ignore error, returns error only if transaction can't be committed. + tr.db.waitCompaction() } + // Only mark as done if transaction committed successfully. + tr.setDone() return nil } @@ -245,10 +266,20 @@ func (tr *Transaction) Discard() { tr.lk.Unlock() } +func (db *DB) waitCompaction() error { + if db.s.tLen(0) >= db.s.o.GetWriteL0PauseTrigger() { + return db.compTriggerWait(db.tcompCmdC) + } + return nil +} + // OpenTransaction opens an atomic DB transaction. Only one transaction can be -// opened at a time. Write will be blocked until the transaction is committed or -// discarded. -// The returned transaction handle is goroutine-safe. +// opened at a time. Subsequent call to Write and OpenTransaction will be blocked +// 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 size is small. Use with caution. // // The transaction must be closed once done, either by committing or discarding // the transaction. @@ -263,7 +294,7 @@ func (db *DB) OpenTransaction() (*Transaction, error) { case db.writeLockC <- struct{}{}: case err := <-db.compPerErrC: return nil, err - case _, _ = <-db.closeC: + case <-db.closeC: return nil, ErrClosed } @@ -278,6 +309,11 @@ func (db *DB) OpenTransaction() (*Transaction, error) { } } + // Wait compaction when certain threshold reached. + if err := db.waitCompaction(); err != nil { + return nil, err + } + tr := &Transaction{ db: db, seq: db.seq, |