0acaa1a846
Summary: Currently, we are tracking keys we need to rollback via a separate structure specific to WriteUnprepared in write_set_keys_. We already have a data structure called tracked_keys_ used to track which keys to unlock on transaction termination. This is exactly what we want, since we should only rollback keys that we have locked anyway. Save some memory by reusing that data structure instead of making our own. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5562 Differential Revision: D16206484 Pulled By: lth fbshipit-source-id: 5894d2b824a4b19062d84adbd6e6e86f00047488
402 lines
14 KiB
C++
402 lines
14 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#ifndef ROCKSDB_LITE
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#include "utilities/transactions/write_unprepared_txn_db.h"
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#include "rocksdb/utilities/transaction_db.h"
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#include "util/cast_util.h"
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namespace rocksdb {
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// Instead of reconstructing a Transaction object, and calling rollback on it,
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// we can be more efficient with RollbackRecoveredTransaction by skipping
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// unnecessary steps (eg. updating CommitMap, reconstructing keyset)
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Status WriteUnpreparedTxnDB::RollbackRecoveredTransaction(
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const DBImpl::RecoveredTransaction* rtxn) {
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// TODO(lth): Reduce duplicate code with WritePrepared rollback logic.
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assert(rtxn->unprepared_);
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auto cf_map_shared_ptr = WritePreparedTxnDB::GetCFHandleMap();
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auto cf_comp_map_shared_ptr = WritePreparedTxnDB::GetCFComparatorMap();
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WriteOptions w_options;
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// If we crash during recovery, we can just recalculate and rewrite the
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// rollback batch.
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w_options.disableWAL = true;
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class InvalidSnapshotReadCallback : public ReadCallback {
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public:
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InvalidSnapshotReadCallback(SequenceNumber snapshot)
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: ReadCallback(snapshot) {}
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inline bool IsVisibleFullCheck(SequenceNumber) override {
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// The seq provided as snapshot is the seq right before we have locked and
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// wrote to it, so whatever is there, it is committed.
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return true;
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}
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// Ignore the refresh request since we are confident that our snapshot seq
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// is not going to be affected by concurrent compactions (not enabled yet.)
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void Refresh(SequenceNumber) override {}
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};
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// Iterate starting with largest sequence number.
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for (auto it = rtxn->batches_.rbegin(); it != rtxn->batches_.rend(); ++it) {
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auto last_visible_txn = it->first - 1;
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const auto& batch = it->second.batch_;
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WriteBatch rollback_batch;
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struct RollbackWriteBatchBuilder : public WriteBatch::Handler {
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DBImpl* db_;
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ReadOptions roptions;
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InvalidSnapshotReadCallback callback;
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WriteBatch* rollback_batch_;
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std::map<uint32_t, const Comparator*>& comparators_;
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std::map<uint32_t, ColumnFamilyHandle*>& handles_;
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using CFKeys = std::set<Slice, SetComparator>;
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std::map<uint32_t, CFKeys> keys_;
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bool rollback_merge_operands_;
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RollbackWriteBatchBuilder(
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DBImpl* db, SequenceNumber snap_seq, WriteBatch* dst_batch,
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std::map<uint32_t, const Comparator*>& comparators,
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std::map<uint32_t, ColumnFamilyHandle*>& handles,
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bool rollback_merge_operands)
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: db_(db),
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callback(snap_seq),
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// disable min_uncommitted optimization
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rollback_batch_(dst_batch),
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comparators_(comparators),
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handles_(handles),
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rollback_merge_operands_(rollback_merge_operands) {}
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Status Rollback(uint32_t cf, const Slice& key) {
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Status s;
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CFKeys& cf_keys = keys_[cf];
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if (cf_keys.size() == 0) { // just inserted
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auto cmp = comparators_[cf];
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keys_[cf] = CFKeys(SetComparator(cmp));
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}
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auto res = cf_keys.insert(key);
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if (res.second ==
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false) { // second is false if a element already existed.
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return s;
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}
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PinnableSlice pinnable_val;
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bool not_used;
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auto cf_handle = handles_[cf];
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s = db_->GetImpl(roptions, cf_handle, key, &pinnable_val, ¬_used,
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&callback);
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assert(s.ok() || s.IsNotFound());
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if (s.ok()) {
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s = rollback_batch_->Put(cf_handle, key, pinnable_val);
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assert(s.ok());
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} else if (s.IsNotFound()) {
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// There has been no readable value before txn. By adding a delete we
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// make sure that there will be none afterwards either.
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s = rollback_batch_->Delete(cf_handle, key);
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assert(s.ok());
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} else {
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// Unexpected status. Return it to the user.
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}
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return s;
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}
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Status PutCF(uint32_t cf, const Slice& key,
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const Slice& /*val*/) override {
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return Rollback(cf, key);
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}
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Status DeleteCF(uint32_t cf, const Slice& key) override {
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return Rollback(cf, key);
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}
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Status SingleDeleteCF(uint32_t cf, const Slice& key) override {
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return Rollback(cf, key);
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}
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Status MergeCF(uint32_t cf, const Slice& key,
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const Slice& /*val*/) override {
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if (rollback_merge_operands_) {
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return Rollback(cf, key);
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} else {
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return Status::OK();
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}
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}
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// Recovered batches do not contain 2PC markers.
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Status MarkNoop(bool) override { return Status::InvalidArgument(); }
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Status MarkBeginPrepare(bool) override {
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return Status::InvalidArgument();
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}
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Status MarkEndPrepare(const Slice&) override {
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return Status::InvalidArgument();
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}
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Status MarkCommit(const Slice&) override {
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return Status::InvalidArgument();
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}
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Status MarkRollback(const Slice&) override {
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return Status::InvalidArgument();
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}
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} rollback_handler(db_impl_, last_visible_txn, &rollback_batch,
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*cf_comp_map_shared_ptr.get(), *cf_map_shared_ptr.get(),
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txn_db_options_.rollback_merge_operands);
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auto s = batch->Iterate(&rollback_handler);
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if (!s.ok()) {
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return s;
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}
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// The Rollback marker will be used as a batch separator
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WriteBatchInternal::MarkRollback(&rollback_batch, rtxn->name_);
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const uint64_t kNoLogRef = 0;
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const bool kDisableMemtable = true;
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const size_t kOneBatch = 1;
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uint64_t seq_used = kMaxSequenceNumber;
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s = db_impl_->WriteImpl(w_options, &rollback_batch, nullptr, nullptr,
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kNoLogRef, !kDisableMemtable, &seq_used, kOneBatch);
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if (!s.ok()) {
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return s;
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}
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// If two_write_queues, we must manually release the sequence number to
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// readers.
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if (db_impl_->immutable_db_options().two_write_queues) {
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db_impl_->SetLastPublishedSequence(seq_used);
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}
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}
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return Status::OK();
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}
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Status WriteUnpreparedTxnDB::Initialize(
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const std::vector<size_t>& compaction_enabled_cf_indices,
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const std::vector<ColumnFamilyHandle*>& handles) {
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// TODO(lth): Reduce code duplication in this function.
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auto dbimpl = reinterpret_cast<DBImpl*>(GetRootDB());
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assert(dbimpl != nullptr);
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db_impl_->SetSnapshotChecker(new WritePreparedSnapshotChecker(this));
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// A callback to commit a single sub-batch
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class CommitSubBatchPreReleaseCallback : public PreReleaseCallback {
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public:
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explicit CommitSubBatchPreReleaseCallback(WritePreparedTxnDB* db)
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: db_(db) {}
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Status Callback(SequenceNumber commit_seq,
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bool is_mem_disabled __attribute__((__unused__)), uint64_t,
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size_t /*index*/, size_t /*total*/) override {
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assert(!is_mem_disabled);
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db_->AddCommitted(commit_seq, commit_seq);
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return Status::OK();
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}
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private:
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WritePreparedTxnDB* db_;
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};
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db_impl_->SetRecoverableStatePreReleaseCallback(
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new CommitSubBatchPreReleaseCallback(this));
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// PessimisticTransactionDB::Initialize
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for (auto cf_ptr : handles) {
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AddColumnFamily(cf_ptr);
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}
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// Verify cf options
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for (auto handle : handles) {
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ColumnFamilyDescriptor cfd;
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Status s = handle->GetDescriptor(&cfd);
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if (!s.ok()) {
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return s;
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}
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s = VerifyCFOptions(cfd.options);
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if (!s.ok()) {
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return s;
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}
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}
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// Re-enable compaction for the column families that initially had
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// compaction enabled.
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std::vector<ColumnFamilyHandle*> compaction_enabled_cf_handles;
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compaction_enabled_cf_handles.reserve(compaction_enabled_cf_indices.size());
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for (auto index : compaction_enabled_cf_indices) {
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compaction_enabled_cf_handles.push_back(handles[index]);
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}
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// create 'real' transactions from recovered shell transactions
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auto rtxns = dbimpl->recovered_transactions();
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std::map<SequenceNumber, SequenceNumber> ordered_seq_cnt;
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for (auto rtxn : rtxns) {
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auto recovered_trx = rtxn.second;
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assert(recovered_trx);
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assert(recovered_trx->batches_.size() >= 1);
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assert(recovered_trx->name_.length());
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// We can only rollback transactions after AdvanceMaxEvictedSeq is called,
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// but AddPrepared must occur before AdvanceMaxEvictedSeq, which is why
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// two iterations is required.
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if (recovered_trx->unprepared_) {
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continue;
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}
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WriteOptions w_options;
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w_options.sync = true;
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TransactionOptions t_options;
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auto first_log_number = recovered_trx->batches_.begin()->second.log_number_;
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auto first_seq = recovered_trx->batches_.begin()->first;
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auto last_prepare_batch_cnt =
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recovered_trx->batches_.begin()->second.batch_cnt_;
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Transaction* real_trx = BeginTransaction(w_options, t_options, nullptr);
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assert(real_trx);
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auto wupt =
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static_cast_with_check<WriteUnpreparedTxn, Transaction>(real_trx);
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wupt->recovered_txn_ = true;
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real_trx->SetLogNumber(first_log_number);
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real_trx->SetId(first_seq);
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Status s = real_trx->SetName(recovered_trx->name_);
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if (!s.ok()) {
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return s;
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}
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wupt->prepare_batch_cnt_ = last_prepare_batch_cnt;
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for (auto batch : recovered_trx->batches_) {
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const auto& seq = batch.first;
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const auto& batch_info = batch.second;
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auto cnt = batch_info.batch_cnt_ ? batch_info.batch_cnt_ : 1;
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assert(batch_info.log_number_);
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ordered_seq_cnt[seq] = cnt;
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assert(wupt->unprep_seqs_.count(seq) == 0);
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wupt->unprep_seqs_[seq] = cnt;
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s = wupt->RebuildFromWriteBatch(batch_info.batch_);
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assert(s.ok());
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if (!s.ok()) {
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return s;
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}
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}
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wupt->write_batch_.Clear();
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WriteBatchInternal::InsertNoop(wupt->write_batch_.GetWriteBatch());
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real_trx->SetState(Transaction::PREPARED);
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if (!s.ok()) {
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return s;
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}
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}
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// AddPrepared must be called in order
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for (auto seq_cnt: ordered_seq_cnt) {
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auto seq = seq_cnt.first;
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auto cnt = seq_cnt.second;
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for (size_t i = 0; i < cnt; i++) {
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AddPrepared(seq + i);
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}
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}
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SequenceNumber prev_max = max_evicted_seq_;
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SequenceNumber last_seq = db_impl_->GetLatestSequenceNumber();
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AdvanceMaxEvictedSeq(prev_max, last_seq);
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// Create a gap between max and the next snapshot. This simplifies the logic
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// in IsInSnapshot by not having to consider the special case of max ==
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// snapshot after recovery. This is tested in IsInSnapshotEmptyMapTest.
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if (last_seq) {
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db_impl_->versions_->SetLastAllocatedSequence(last_seq + 1);
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db_impl_->versions_->SetLastSequence(last_seq + 1);
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db_impl_->versions_->SetLastPublishedSequence(last_seq + 1);
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}
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Status s;
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// Rollback unprepared transactions.
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for (auto rtxn : rtxns) {
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auto recovered_trx = rtxn.second;
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if (recovered_trx->unprepared_) {
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s = RollbackRecoveredTransaction(recovered_trx);
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if (!s.ok()) {
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return s;
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}
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continue;
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}
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}
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if (s.ok()) {
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dbimpl->DeleteAllRecoveredTransactions();
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// Compaction should start only after max_evicted_seq_ is set AND recovered
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// transactions are either added to PrepareHeap or rolled back.
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s = EnableAutoCompaction(compaction_enabled_cf_handles);
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}
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return s;
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}
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Transaction* WriteUnpreparedTxnDB::BeginTransaction(
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const WriteOptions& write_options, const TransactionOptions& txn_options,
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Transaction* old_txn) {
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if (old_txn != nullptr) {
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ReinitializeTransaction(old_txn, write_options, txn_options);
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return old_txn;
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} else {
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return new WriteUnpreparedTxn(this, write_options, txn_options);
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}
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}
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// Struct to hold ownership of snapshot and read callback for iterator cleanup.
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struct WriteUnpreparedTxnDB::IteratorState {
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IteratorState(WritePreparedTxnDB* txn_db, SequenceNumber sequence,
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std::shared_ptr<ManagedSnapshot> s,
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SequenceNumber min_uncommitted, WriteUnpreparedTxn* txn)
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: callback(txn_db, sequence, min_uncommitted, txn), snapshot(s) {}
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SequenceNumber MaxVisibleSeq() { return callback.max_visible_seq(); }
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WriteUnpreparedTxnReadCallback callback;
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std::shared_ptr<ManagedSnapshot> snapshot;
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};
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namespace {
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static void CleanupWriteUnpreparedTxnDBIterator(void* arg1, void* /*arg2*/) {
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delete reinterpret_cast<WriteUnpreparedTxnDB::IteratorState*>(arg1);
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}
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} // anonymous namespace
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Iterator* WriteUnpreparedTxnDB::NewIterator(const ReadOptions& options,
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ColumnFamilyHandle* column_family,
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WriteUnpreparedTxn* txn) {
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// TODO(lth): Refactor so that this logic is shared with WritePrepared.
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constexpr bool ALLOW_BLOB = true;
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constexpr bool ALLOW_REFRESH = true;
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std::shared_ptr<ManagedSnapshot> own_snapshot = nullptr;
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SequenceNumber snapshot_seq;
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SequenceNumber min_uncommitted = 0;
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if (options.snapshot != nullptr) {
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snapshot_seq = options.snapshot->GetSequenceNumber();
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min_uncommitted =
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static_cast_with_check<const SnapshotImpl, const Snapshot>(
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options.snapshot)
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->min_uncommitted_;
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} else {
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auto* snapshot = GetSnapshot();
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// We take a snapshot to make sure that the related data in the commit map
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// are not deleted.
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snapshot_seq = snapshot->GetSequenceNumber();
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min_uncommitted =
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static_cast_with_check<const SnapshotImpl, const Snapshot>(snapshot)
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->min_uncommitted_;
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own_snapshot = std::make_shared<ManagedSnapshot>(db_impl_, snapshot);
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}
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assert(snapshot_seq != kMaxSequenceNumber);
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auto* cfd = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family)->cfd();
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auto* state =
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new IteratorState(this, snapshot_seq, own_snapshot, min_uncommitted, txn);
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auto* db_iter =
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db_impl_->NewIteratorImpl(options, cfd, state->MaxVisibleSeq(),
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&state->callback, !ALLOW_BLOB, !ALLOW_REFRESH);
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db_iter->RegisterCleanup(CleanupWriteUnpreparedTxnDBIterator, state, nullptr);
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return db_iter;
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}
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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