@ -46,7 +46,436 @@ SequenceNumber WriteUnpreparedTxnReadCallback::MaxUnpreparedSequenceNumber() {
WriteUnpreparedTxn : : WriteUnpreparedTxn ( WriteUnpreparedTxnDB * txn_db ,
const WriteOptions & write_options ,
const TransactionOptions & txn_options )
: WritePreparedTxn ( txn_db , write_options , txn_options ) , wupt_db_ ( txn_db ) { }
: WritePreparedTxn ( txn_db , write_options , txn_options ) , wupt_db_ ( txn_db ) {
max_write_batch_size_ = txn_options . max_write_batch_size ;
// We set max bytes to zero so that we don't get a memory limit error.
// Instead of trying to keep write batch strictly under the size limit, we
// just flush to DB when the limit is exceeded in write unprepared, to avoid
// having retry logic. This also allows very big key-value pairs that exceed
// max bytes to succeed.
write_batch_ . SetMaxBytes ( 0 ) ;
}
WriteUnpreparedTxn : : ~ WriteUnpreparedTxn ( ) {
if ( ! unprep_seqs_ . empty ( ) ) {
assert ( log_number_ > 0 ) ;
assert ( GetId ( ) > 0 ) ;
assert ( ! name_ . empty ( ) ) ;
// We should rollback regardless of GetState, but some unit tests that
// test crash recovery run the destructor assuming that rollback does not
// happen, so that rollback during recovery can be exercised.
if ( GetState ( ) = = STARTED ) {
auto s __attribute__ ( ( __unused__ ) ) = RollbackInternal ( ) ;
// TODO(lth): Better error handling.
assert ( s . ok ( ) ) ;
dbimpl_ - > logs_with_prep_tracker ( ) - > MarkLogAsHavingPrepSectionFlushed (
log_number_ ) ;
}
}
}
void WriteUnpreparedTxn : : Initialize ( const TransactionOptions & txn_options ) {
PessimisticTransaction : : Initialize ( txn_options ) ;
max_write_batch_size_ = txn_options . max_write_batch_size ;
write_batch_ . SetMaxBytes ( 0 ) ;
unprep_seqs_ . clear ( ) ;
write_set_keys_ . clear ( ) ;
}
Status WriteUnpreparedTxn : : Put ( ColumnFamilyHandle * column_family ,
const Slice & key , const Slice & value ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : Put ( column_family , key , value ) ;
}
Status WriteUnpreparedTxn : : Put ( ColumnFamilyHandle * column_family ,
const SliceParts & key , const SliceParts & value ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : Put ( column_family , key , value ) ;
}
Status WriteUnpreparedTxn : : Merge ( ColumnFamilyHandle * column_family ,
const Slice & key , const Slice & value ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : Merge ( column_family , key , value ) ;
}
Status WriteUnpreparedTxn : : Delete ( ColumnFamilyHandle * column_family ,
const Slice & key ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : Delete ( column_family , key ) ;
}
Status WriteUnpreparedTxn : : Delete ( ColumnFamilyHandle * column_family ,
const SliceParts & key ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : Delete ( column_family , key ) ;
}
Status WriteUnpreparedTxn : : SingleDelete ( ColumnFamilyHandle * column_family ,
const Slice & key ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : SingleDelete ( column_family , key ) ;
}
Status WriteUnpreparedTxn : : SingleDelete ( ColumnFamilyHandle * column_family ,
const SliceParts & key ) {
Status s = MaybeFlushWriteBatchToDB ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return TransactionBaseImpl : : SingleDelete ( column_family , key ) ;
}
Status WriteUnpreparedTxn : : MaybeFlushWriteBatchToDB ( ) {
const bool kPrepared = true ;
Status s ;
bool needs_mark = ( log_number_ = = 0 ) ;
if ( max_write_batch_size_ ! = 0 & &
write_batch_ . GetDataSize ( ) > max_write_batch_size_ ) {
assert ( GetState ( ) ! = PREPARED ) ;
s = FlushWriteBatchToDB ( ! kPrepared ) ;
if ( s . ok ( ) ) {
assert ( log_number_ > 0 ) ;
// This is done to prevent WAL files after log_number_ from being
// deleted, because they could potentially contain unprepared batches.
if ( needs_mark ) {
dbimpl_ - > logs_with_prep_tracker ( ) - > MarkLogAsContainingPrepSection (
log_number_ ) ;
}
}
}
return s ;
}
void WriteUnpreparedTxn : : UpdateWriteKeySet ( uint32_t cfid , const Slice & key ) {
// TODO(lth): write_set_keys_ can just be a std::string instead of a vector.
write_set_keys_ [ cfid ] . push_back ( key . ToString ( ) ) ;
}
Status WriteUnpreparedTxn : : FlushWriteBatchToDB ( bool prepared ) {
if ( name_ . empty ( ) ) {
return Status : : InvalidArgument ( " Cannot write to DB without SetName. " ) ;
}
// Update write_key_set_ for rollback purposes.
KeySetBuilder keyset_handler (
this , wupt_db_ - > txn_db_options_ . rollback_merge_operands ) ;
auto s = GetWriteBatch ( ) - > GetWriteBatch ( ) - > Iterate ( & keyset_handler ) ;
assert ( s . ok ( ) ) ;
if ( ! s . ok ( ) ) {
return s ;
}
// TODO(lth): Reduce duplicate code with WritePrepared prepare logic.
WriteOptions write_options = write_options_ ;
write_options . disableWAL = false ;
const bool WRITE_AFTER_COMMIT = true ;
// MarkEndPrepare will change Noop marker to the appropriate marker.
WriteBatchInternal : : MarkEndPrepare ( GetWriteBatch ( ) - > GetWriteBatch ( ) , name_ ,
! WRITE_AFTER_COMMIT , ! prepared ) ;
// For each duplicate key we account for a new sub-batch
prepare_batch_cnt_ = GetWriteBatch ( ) - > SubBatchCnt ( ) ;
// AddPrepared better to be called in the pre-release callback otherwise there
// is a non-zero chance of max advancing prepare_seq and readers assume the
// data as committed.
// Also having it in the PreReleaseCallback allows in-order addition of
// prepared entries to PrepareHeap and hence enables an optimization. Refer to
// SmallestUnCommittedSeq for more details.
AddPreparedCallback add_prepared_callback (
wpt_db_ , prepare_batch_cnt_ ,
db_impl_ - > immutable_db_options ( ) . two_write_queues ) ;
const bool DISABLE_MEMTABLE = true ;
uint64_t seq_used = kMaxSequenceNumber ;
// log_number_ should refer to the oldest log containing uncommitted data
// from the current transaction. This means that if log_number_ is set,
// WriteImpl should not overwrite that value, so set log_used to nullptr if
// log_number_ is already set.
uint64_t * log_used = log_number_ ? nullptr : & log_number_ ;
s = db_impl_ - > WriteImpl ( write_options , GetWriteBatch ( ) - > GetWriteBatch ( ) ,
/*callback*/ nullptr , log_used , /*log ref*/
0 , ! DISABLE_MEMTABLE , & seq_used , prepare_batch_cnt_ ,
& add_prepared_callback ) ;
assert ( ! s . ok ( ) | | seq_used ! = kMaxSequenceNumber ) ;
auto prepare_seq = seq_used ;
// Only call SetId if it hasn't been set yet.
if ( GetId ( ) = = 0 ) {
SetId ( prepare_seq ) ;
}
// unprep_seqs_ will also contain prepared seqnos since they are treated in
// the same way in the prepare/commit callbacks. See the comment on the
// definition of unprep_seqs_.
unprep_seqs_ [ prepare_seq ] = prepare_batch_cnt_ ;
// Reset transaction state.
if ( ! prepared ) {
prepare_batch_cnt_ = 0 ;
write_batch_ . Clear ( ) ;
WriteBatchInternal : : InsertNoop ( write_batch_ . GetWriteBatch ( ) ) ;
}
return s ;
}
Status WriteUnpreparedTxn : : PrepareInternal ( ) {
const bool kPrepared = true ;
return FlushWriteBatchToDB ( kPrepared ) ;
}
Status WriteUnpreparedTxn : : CommitWithoutPrepareInternal ( ) {
if ( unprep_seqs_ . empty ( ) ) {
assert ( log_number_ = = 0 ) ;
assert ( GetId ( ) = = 0 ) ;
return WritePreparedTxn : : CommitWithoutPrepareInternal ( ) ;
}
// TODO(lth): We should optimize commit without prepare to not perform
// a prepare under the hood.
auto s = PrepareInternal ( ) ;
if ( ! s . ok ( ) ) {
return s ;
}
return CommitInternal ( ) ;
}
Status WriteUnpreparedTxn : : CommitInternal ( ) {
// TODO(lth): Reduce duplicate code with WritePrepared commit logic.
// We take the commit-time batch and append the Commit marker. The Memtable
// will ignore the Commit marker in non-recovery mode
WriteBatch * working_batch = GetCommitTimeWriteBatch ( ) ;
const bool empty = working_batch - > Count ( ) = = 0 ;
WriteBatchInternal : : MarkCommit ( working_batch , name_ ) ;
const bool for_recovery = use_only_the_last_commit_time_batch_for_recovery_ ;
if ( ! empty & & for_recovery ) {
// When not writing to memtable, we can still cache the latest write batch.
// The cached batch will be written to memtable in WriteRecoverableState
// during FlushMemTable
WriteBatchInternal : : SetAsLastestPersistentState ( working_batch ) ;
}
const bool includes_data = ! empty & & ! for_recovery ;
size_t commit_batch_cnt = 0 ;
if ( UNLIKELY ( includes_data ) ) {
ROCKS_LOG_WARN ( db_impl_ - > immutable_db_options ( ) . info_log ,
" Duplicate key overhead " ) ;
SubBatchCounter counter ( * wpt_db_ - > GetCFComparatorMap ( ) ) ;
auto s = working_batch - > Iterate ( & counter ) ;
assert ( s . ok ( ) ) ;
commit_batch_cnt = counter . BatchCount ( ) ;
}
const bool disable_memtable = ! includes_data ;
const bool do_one_write =
! db_impl_ - > immutable_db_options ( ) . two_write_queues | | disable_memtable ;
const bool publish_seq = do_one_write ;
// Note: CommitTimeWriteBatch does not need AddPrepared since it is written to
// DB in one shot. min_uncommitted still works since it requires capturing
// data that is written to DB but not yet committed, while
// CommitTimeWriteBatch commits with PreReleaseCallback.
WriteUnpreparedCommitEntryPreReleaseCallback update_commit_map (
wpt_db_ , db_impl_ , unprep_seqs_ , commit_batch_cnt , publish_seq ) ;
uint64_t seq_used = kMaxSequenceNumber ;
// Since the prepared batch is directly written to memtable, there is already
// a connection between the memtable and its WAL, so there is no need to
// redundantly reference the log that contains the prepared data.
const uint64_t zero_log_number = 0ull ;
size_t batch_cnt = UNLIKELY ( commit_batch_cnt ) ? commit_batch_cnt : 1 ;
auto s = db_impl_ - > WriteImpl ( write_options_ , working_batch , nullptr , nullptr ,
zero_log_number , disable_memtable , & seq_used ,
batch_cnt , & update_commit_map ) ;
assert ( ! s . ok ( ) | | seq_used ! = kMaxSequenceNumber ) ;
if ( LIKELY ( do_one_write | | ! s . ok ( ) ) ) {
if ( LIKELY ( s . ok ( ) ) ) {
// Note RemovePrepared should be called after WriteImpl that publishsed
// the seq. Otherwise SmallestUnCommittedSeq optimization breaks.
for ( const auto & seq : unprep_seqs_ ) {
wpt_db_ - > RemovePrepared ( seq . first , seq . second ) ;
}
}
unprep_seqs_ . clear ( ) ;
write_set_keys_ . clear ( ) ;
return s ;
} // else do the 2nd write to publish seq
// Note: the 2nd write comes with a performance penality. So if we have too
// many of commits accompanied with ComitTimeWriteBatch and yet we cannot
// enable use_only_the_last_commit_time_batch_for_recovery_ optimization,
// two_write_queues should be disabled to avoid many additional writes here.
class PublishSeqPreReleaseCallback : public PreReleaseCallback {
public :
explicit PublishSeqPreReleaseCallback ( DBImpl * db_impl )
: db_impl_ ( db_impl ) { }
virtual Status Callback ( SequenceNumber seq , bool is_mem_disabled
__attribute__ ( ( __unused__ ) ) ) override {
assert ( is_mem_disabled ) ;
assert ( db_impl_ - > immutable_db_options ( ) . two_write_queues ) ;
db_impl_ - > SetLastPublishedSequence ( seq ) ;
return Status : : OK ( ) ;
}
private :
DBImpl * db_impl_ ;
} publish_seq_callback ( db_impl_ ) ;
WriteBatch empty_batch ;
empty_batch . PutLogData ( Slice ( ) ) ;
// In the absence of Prepare markers, use Noop as a batch separator
WriteBatchInternal : : InsertNoop ( & empty_batch ) ;
const bool DISABLE_MEMTABLE = true ;
const size_t ONE_BATCH = 1 ;
const uint64_t NO_REF_LOG = 0 ;
s = db_impl_ - > WriteImpl ( write_options_ , & empty_batch , nullptr , nullptr ,
NO_REF_LOG , DISABLE_MEMTABLE , & seq_used , ONE_BATCH ,
& publish_seq_callback ) ;
assert ( ! s . ok ( ) | | seq_used ! = kMaxSequenceNumber ) ;
// Note RemovePrepared should be called after WriteImpl that publishsed the
// seq. Otherwise SmallestUnCommittedSeq optimization breaks.
for ( const auto & seq : unprep_seqs_ ) {
wpt_db_ - > RemovePrepared ( seq . first , seq . second ) ;
}
unprep_seqs_ . clear ( ) ;
write_set_keys_ . clear ( ) ;
return s ;
}
Status WriteUnpreparedTxn : : RollbackInternal ( ) {
// TODO(lth): Reduce duplicate code with WritePrepared rollback logic.
WriteBatchWithIndex rollback_batch (
wpt_db_ - > DefaultColumnFamily ( ) - > GetComparator ( ) , 0 , true , 0 ) ;
assert ( GetId ( ) ! = kMaxSequenceNumber ) ;
assert ( GetId ( ) > 0 ) ;
const auto & cf_map = * wupt_db_ - > GetCFHandleMap ( ) ;
// In WritePrepared, the txn is is the same as prepare seq
auto last_visible_txn = GetId ( ) - 1 ;
Status s ;
ReadOptions roptions ;
// Note that we do not use WriteUnpreparedTxnReadCallback because we do not
// need to read our own writes when reading prior versions of the key for
// rollback.
WritePreparedTxnReadCallback callback ( wpt_db_ , last_visible_txn , 0 ) ;
for ( const auto & cfkey : write_set_keys_ ) {
const auto cfid = cfkey . first ;
const auto & keys = cfkey . second ;
for ( const auto & key : keys ) {
const auto & cf_handle = cf_map . at ( cfid ) ;
PinnableSlice pinnable_val ;
bool not_used ;
s = db_impl_ - > GetImpl ( roptions , cf_handle , key , & pinnable_val , & not_used ,
& callback ) ;
if ( s . ok ( ) ) {
s = rollback_batch . Put ( cf_handle , key , pinnable_val ) ;
assert ( s . ok ( ) ) ;
} else if ( s . IsNotFound ( ) ) {
s = rollback_batch . Delete ( cf_handle , key ) ;
assert ( s . ok ( ) ) ;
} else {
return s ;
}
}
}
// The Rollback marker will be used as a batch separator
WriteBatchInternal : : MarkRollback ( rollback_batch . GetWriteBatch ( ) , name_ ) ;
bool do_one_write = ! db_impl_ - > immutable_db_options ( ) . two_write_queues ;
const bool DISABLE_MEMTABLE = true ;
const uint64_t NO_REF_LOG = 0 ;
uint64_t seq_used = kMaxSequenceNumber ;
// TODO(lth): We write rollback batch all in a single batch here, but this
// should be subdivded into multiple batches as well. In phase 2, when key
// sets are read from WAL, this will happen naturally.
const size_t ONE_BATCH = 1 ;
// We commit the rolled back prepared batches. ALthough this is
// counter-intuitive, i) it is safe to do so, since the prepared batches are
// already canceled out by the rollback batch, ii) adding the commit entry to
// CommitCache will allow us to benefit from the existing mechanism in
// CommitCache that keeps an entry evicted due to max advance and yet overlaps
// with a live snapshot around so that the live snapshot properly skips the
// entry even if its prepare seq is lower than max_evicted_seq_.
WriteUnpreparedCommitEntryPreReleaseCallback update_commit_map (
wpt_db_ , db_impl_ , unprep_seqs_ , ONE_BATCH ) ;
// Note: the rollback batch does not need AddPrepared since it is written to
// DB in one shot. min_uncommitted still works since it requires capturing
// data that is written to DB but not yet committed, while the roolback
// batch commits with PreReleaseCallback.
s = db_impl_ - > WriteImpl ( write_options_ , rollback_batch . GetWriteBatch ( ) ,
nullptr , nullptr , NO_REF_LOG , ! DISABLE_MEMTABLE ,
& seq_used , rollback_batch . SubBatchCnt ( ) ,
do_one_write ? & update_commit_map : nullptr ) ;
assert ( ! s . ok ( ) | | seq_used ! = kMaxSequenceNumber ) ;
if ( ! s . ok ( ) ) {
return s ;
}
if ( do_one_write ) {
for ( const auto & seq : unprep_seqs_ ) {
wpt_db_ - > RemovePrepared ( seq . first , seq . second ) ;
}
unprep_seqs_ . clear ( ) ;
write_set_keys_ . clear ( ) ;
return s ;
} // else do the 2nd write for commit
uint64_t & prepare_seq = seq_used ;
ROCKS_LOG_DETAILS ( db_impl_ - > immutable_db_options ( ) . info_log ,
" RollbackInternal 2nd write prepare_seq: % " PRIu64 ,
prepare_seq ) ;
// Commit the batch by writing an empty batch to the queue that will release
// the commit sequence number to readers.
const size_t ZERO_COMMITS = 0 ;
WritePreparedCommitEntryPreReleaseCallback update_commit_map_with_prepare (
wpt_db_ , db_impl_ , prepare_seq , ONE_BATCH , ZERO_COMMITS ) ;
WriteBatch empty_batch ;
empty_batch . PutLogData ( Slice ( ) ) ;
// In the absence of Prepare markers, use Noop as a batch separator
WriteBatchInternal : : InsertNoop ( & empty_batch ) ;
s = db_impl_ - > WriteImpl ( write_options_ , & empty_batch , nullptr , nullptr ,
NO_REF_LOG , DISABLE_MEMTABLE , & seq_used , ONE_BATCH ,
& update_commit_map_with_prepare ) ;
assert ( ! s . ok ( ) | | seq_used ! = kMaxSequenceNumber ) ;
// Mark the txn as rolled back
uint64_t & rollback_seq = seq_used ;
if ( s . ok ( ) ) {
// Note: it is safe to do it after PreReleaseCallback via WriteImpl since
// all the writes by the prpared batch are already blinded by the rollback
// batch. The only reason we commit the prepared batch here is to benefit
// from the existing mechanism in CommitCache that takes care of the rare
// cases that the prepare seq is visible to a snsapshot but max evicted seq
// advances that prepare seq.
for ( const auto & seq : unprep_seqs_ ) {
for ( size_t i = 0 ; i < seq . second ; i + + ) {
wpt_db_ - > AddCommitted ( seq . first + i , rollback_seq ) ;
}
}
for ( const auto & seq : unprep_seqs_ ) {
wpt_db_ - > RemovePrepared ( seq . first , seq . second ) ;
}
}
unprep_seqs_ . clear ( ) ;
write_set_keys_ . clear ( ) ;
return s ;
}
Status WriteUnpreparedTxn : : Get ( const ReadOptions & options ,
ColumnFamilyHandle * column_family ,
Manuel Ung
6 years ago
committed by