mirror of https://github.com/facebook/rocksdb.git
84 lines
3.3 KiB
C++
84 lines
3.3 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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#pragma once
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#include <string>
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#include <unordered_map>
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#include "db/dbformat.h"
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#include "db/read_callback.h"
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#include "rocksdb/db.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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#include "utilities/transactions/lock/lock_tracker.h"
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namespace ROCKSDB_NAMESPACE {
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class DBImpl;
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struct SuperVersion;
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class WriteBatchWithIndex;
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class TransactionUtil {
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public:
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// Verifies there have been no commits to this key in the db since this
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// sequence number. If user-defined timestamp is enabled, then also check
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// no commits to this key in the db since the given ts.
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//
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// If cache_only is true, then this function will not attempt to read any
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// SST files. This will make it more likely this function will
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// return an error if it is unable to determine if there are any conflicts.
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//
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// See comment of CheckKey() for explanation of `snap_seq`, `ts`,
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// `snap_checker` and `min_uncommitted`.
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//
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// Returns OK on success, BUSY if there is a conflicting write, or other error
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// status for any unexpected errors.
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static Status CheckKeyForConflicts(
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DBImpl* db_impl, ColumnFamilyHandle* column_family,
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const std::string& key, SequenceNumber snap_seq,
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const std::string* const ts, bool cache_only,
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ReadCallback* snap_checker = nullptr,
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SequenceNumber min_uncommitted = kMaxSequenceNumber);
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// For each key,SequenceNumber pair tracked by the LockTracker, this function
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// will verify there have been no writes to the key in the db since that
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// sequence number.
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//
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// Returns OK on success, BUSY if there is a conflicting write, or other error
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// status for any unexpected errors.
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//
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// REQUIRED:
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// This function should only be called on the write thread or if the
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// mutex is held.
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// tracker must support point lock.
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static Status CheckKeysForConflicts(DBImpl* db_impl,
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const LockTracker& tracker,
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bool cache_only);
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private:
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// If `snap_checker` == nullptr, writes are always commited in sequence number
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// order. All sequence number <= `snap_seq` will not conflict with any
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// write, and all keys > `snap_seq` of `key` will trigger conflict.
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// If `snap_checker` != nullptr, writes may not commit in sequence number
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// order. In this case `min_uncommitted` is a lower bound.
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// seq < `min_uncommitted`: no conflict
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// seq > `snap_seq`: applicable to conflict
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// `min_uncommitted` <= seq <= `snap_seq`: call `snap_checker` to determine.
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//
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// If user-defined timestamp is enabled, a write conflict is detected if an
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// operation for `key` with timestamp greater than `ts` exists.
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static Status CheckKey(DBImpl* db_impl, SuperVersion* sv,
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SequenceNumber earliest_seq, SequenceNumber snap_seq,
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const std::string& key, const std::string* const ts,
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bool cache_only, ReadCallback* snap_checker = nullptr,
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SequenceNumber min_uncommitted = kMaxSequenceNumber);
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};
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} // namespace ROCKSDB_NAMESPACE
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