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6f71d3b68b
Summary: copy from task 8196669: 1) Optimistic transactions do not support batching writes from different threads. 2) Pessimistic transactions do not support batching writes if an expiration time is set. In these 2 cases, we currently do not do any write batching in DBImpl::WriteImpl() because there is a WriteCallback that could decide at the last minute to abort the write. But we could support batching write operations with callbacks if we make sure to process the callbacks correctly. To do this, we would first need to modify write_thread.cc to stop preventing writes with callbacks from being batched together. Then we would need to change DBImpl::WriteImpl() to call all WriteCallback's in a batch, only write the batches that succeed, and correctly set the state of each batch's WriteThread::Writer. Test Plan: Added test WriteWithCallbackTest to write_callback_test.cc which creates multiple client threads and verifies that writes are batched and executed properly. Reviewers: hermanlee4, anthony, ngbronson Subscribers: leveldb, dhruba Differential Revision: https://reviews.facebook.net/D52863
83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
// Copyright (c) 2015, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <stack>
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#include <string>
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#include <unordered_map>
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#include <vector>
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#include "db/write_callback.h"
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#include "rocksdb/db.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/snapshot.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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#include "rocksdb/utilities/transaction.h"
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#include "rocksdb/utilities/optimistic_transaction_db.h"
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#include "rocksdb/utilities/write_batch_with_index.h"
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#include "utilities/transactions/transaction_base.h"
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#include "utilities/transactions/transaction_util.h"
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namespace rocksdb {
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class OptimisticTransactionImpl : public TransactionBaseImpl {
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public:
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OptimisticTransactionImpl(OptimisticTransactionDB* db,
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const WriteOptions& write_options,
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const OptimisticTransactionOptions& txn_options);
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virtual ~OptimisticTransactionImpl();
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Status Commit() override;
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void Rollback() override;
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protected:
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Status TryLock(ColumnFamilyHandle* column_family, const Slice& key,
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bool untracked = false) override;
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private:
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OptimisticTransactionDB* const txn_db_;
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friend class OptimisticTransactionCallback;
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// Returns OK if it is safe to commit this transaction. Returns Status::Busy
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// if there are read or write conflicts that would prevent us from committing
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// OR if we can not determine whether there would be any such conflicts.
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//
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// Should only be called on writer thread.
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Status CheckTransactionForConflicts(DB* db);
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void Clear() override;
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// No copying allowed
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OptimisticTransactionImpl(const OptimisticTransactionImpl&);
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void operator=(const OptimisticTransactionImpl&);
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};
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// Used at commit time to trigger transaction validation
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class OptimisticTransactionCallback : public WriteCallback {
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public:
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explicit OptimisticTransactionCallback(OptimisticTransactionImpl* txn)
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: txn_(txn) {}
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Status Callback(DB* db) override {
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return txn_->CheckTransactionForConflicts(db);
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}
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bool AllowWriteBatching() override { return false; }
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private:
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OptimisticTransactionImpl* txn_;
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};
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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