diff options
Diffstat (limited to 'src/mongo/db/operation_context.h')
| -rw-r--r-- | src/mongo/db/operation_context.h | 455 |
1 files changed, 229 insertions, 226 deletions
diff --git a/src/mongo/db/operation_context.h b/src/mongo/db/operation_context.h index e7a05b65b20..741279f48e0 100644 --- a/src/mongo/db/operation_context.h +++ b/src/mongo/db/operation_context.h @@ -38,253 +38,256 @@ namespace mongo { - class Client; - class CurOp; - class Locker; - class ProgressMeter; - class StringData; - class WriteUnitOfWork; +class Client; +class CurOp; +class Locker; +class ProgressMeter; +class StringData; +class WriteUnitOfWork; +/** + * This class encompasses the state required by an operation and lives from the time a network + * peration is dispatched until its execution is finished. Note that each "getmore" on a cursor + * is a separate operation. On construction, an OperationContext associates itself with the + * current client, and only on destruction it deassociates itself. At any time a client can be + * associated with at most one OperationContext. Each OperationContext has a RecoveryUnit + * associated with it, though the lifetime is not necesarily the same, see releaseRecoveryUnit + * and setRecoveryUnit. The operation context also keeps track of some transaction state + * (RecoveryUnitState) to reduce complexity and duplication in the storage-engine specific + * RecoveryUnit and to allow better invariant checking. + */ +class OperationContext : public Decorable<OperationContext> { + MONGO_DISALLOW_COPYING(OperationContext); + +public: /** - * This class encompasses the state required by an operation and lives from the time a network - * peration is dispatched until its execution is finished. Note that each "getmore" on a cursor - * is a separate operation. On construction, an OperationContext associates itself with the - * current client, and only on destruction it deassociates itself. At any time a client can be - * associated with at most one OperationContext. Each OperationContext has a RecoveryUnit - * associated with it, though the lifetime is not necesarily the same, see releaseRecoveryUnit - * and setRecoveryUnit. The operation context also keeps track of some transaction state - * (RecoveryUnitState) to reduce complexity and duplication in the storage-engine specific - * RecoveryUnit and to allow better invariant checking. + * The RecoveryUnitState is used by WriteUnitOfWork to ensure valid state transitions. */ - class OperationContext : public Decorable<OperationContext> { - MONGO_DISALLOW_COPYING(OperationContext); - - public: - /** - * The RecoveryUnitState is used by WriteUnitOfWork to ensure valid state transitions. - */ - enum RecoveryUnitState { - kNotInUnitOfWork, // not in a unit of work, no writes allowed - kActiveUnitOfWork, // in a unit of work that still may either commit or abort - kFailedUnitOfWork // in a unit of work that has failed and must be aborted - }; - - virtual ~OperationContext() = default; - - /** - * Interface for durability. Caller DOES NOT own pointer. - */ - virtual RecoveryUnit* recoveryUnit() const = 0; - - - /** - * Returns the RecoveryUnit (same return value as recoveryUnit()) but the caller takes - * ownership of the returned RecoveryUnit, and the OperationContext instance relinquishes - * ownership. Sets the RecoveryUnit to NULL. - * - * Used to transfer ownership of storage engine state from OperationContext - * to ClientCursor for getMore-able queries. - * - * Note that we don't allow the top-level locks to be stored across getMore. - * We rely on active cursors being killed when collections or databases are dropped, - * or when collection metadata changes. - */ - virtual RecoveryUnit* releaseRecoveryUnit() = 0; - - /** - * Associates the OperatingContext with a different RecoveryUnit for getMore or - * subtransactions, see RecoveryUnitSwap. The new state is passed and the old state is - * returned separately even though the state logically belongs to the RecoveryUnit, - * as it is managed by the OperationContext. - */ - virtual RecoveryUnitState setRecoveryUnit(RecoveryUnit* unit, RecoveryUnitState state) = 0; - - /** - * Interface for locking. Caller DOES NOT own pointer. - */ - Locker* lockState() const { return _locker; } - - // --- operation level info? --- - - /** - * Raises a UserAssertion if this operation is in a killed state. - */ - virtual void checkForInterrupt() = 0; - - /** - * Returns Status::OK() unless this operation is in a killed state. - */ - virtual Status checkForInterruptNoAssert() = 0; - - /** - * Delegates to CurOp, but is included here to break dependencies. - * Caller does not own the pointer. - * - * Caller must have locked the "Client" associated with this context. - */ - virtual ProgressMeter* setMessage_inlock(const char* msg, - const std::string& name = "Progress", - unsigned long long progressMeterTotal = 0, - int secondsBetween = 3) = 0; - - /** - * Delegates to CurOp, but is included here to break dependencies. - * - * TODO: We return a string because of hopefully transient CurOp thread-unsafe insanity. - */ - virtual std::string getNS() const = 0; - - /** - * Returns the client under which this context runs. - */ - Client* getClient() const; - - virtual uint64_t getRemainingMaxTimeMicros() const = 0; - - /** - * Returns the operation ID associated with this operation. - */ - unsigned int getOpID() const { return _opId; } - - /** - * @return true if this instance is primary for this namespace - */ - virtual bool isPrimaryFor( StringData ns ) = 0; - - /** - * Returns WriteConcernOptions of the current operation - */ - const WriteConcernOptions& getWriteConcern() const { - return _writeConcern; - } + enum RecoveryUnitState { + kNotInUnitOfWork, // not in a unit of work, no writes allowed + kActiveUnitOfWork, // in a unit of work that still may either commit or abort + kFailedUnitOfWork // in a unit of work that has failed and must be aborted + }; - void setWriteConcern(const WriteConcernOptions& writeConcern) { - _writeConcern = writeConcern; - } + virtual ~OperationContext() = default; - /** - * Set whether or not operations should generate oplog entries. - */ - virtual void setReplicatedWrites(bool writesAreReplicated = true) = 0; - - /** - * Returns true if operations should generate oplog entries. - */ - virtual bool writesAreReplicated() const = 0; - - /** - * Marks this operation as killed. - * - * Subsequent calls to checkForInterrupt and checkForInterruptNoAssert by the thread - * executing the operation will indicate that the operation has been killed. - * - * May be called by any thread that has locked the Client owning this operation context, - * or by the thread executing on behalf of this operation context. - */ - void markKilled(); - - /** - * Returns true if markKilled has been called on this operation context. - * - * May be called by any thread that has locked the Client owning this operation context, - * or by the thread executing on behalf of this operation context. - */ - bool isKillPending() const; - - protected: - OperationContext(Client* client, - unsigned int opId, - Locker* locker); - - RecoveryUnitState _ruState = kNotInUnitOfWork; - - private: - friend class WriteUnitOfWork; - Client* const _client; - const unsigned int _opId; - - // The lifetime of locker is managed by subclasses of OperationContext, so it is not - // safe to access _locker in the destructor of OperationContext. - Locker* const _locker; - - AtomicInt32 _killPending{0}; - WriteConcernOptions _writeConcern; - }; + /** + * Interface for durability. Caller DOES NOT own pointer. + */ + virtual RecoveryUnit* recoveryUnit() const = 0; - class WriteUnitOfWork { - MONGO_DISALLOW_COPYING(WriteUnitOfWork); - public: - WriteUnitOfWork(OperationContext* txn) - : _txn(txn), - _committed(false), - _toplevel(txn->_ruState == OperationContext::kNotInUnitOfWork) { - _txn->lockState()->beginWriteUnitOfWork(); - if (_toplevel) { - _txn->recoveryUnit()->beginUnitOfWork(_txn); - _txn->_ruState = OperationContext::kActiveUnitOfWork; - } - } - ~WriteUnitOfWork() { - if (!_committed) { - invariant(_txn->_ruState != OperationContext::kNotInUnitOfWork); - if (_toplevel) { - _txn->recoveryUnit()->abortUnitOfWork(); - _txn->_ruState = OperationContext::kNotInUnitOfWork; - } - else { - _txn->_ruState = OperationContext::kFailedUnitOfWork; - } - _txn->lockState()->endWriteUnitOfWork(); - } + /** + * Returns the RecoveryUnit (same return value as recoveryUnit()) but the caller takes + * ownership of the returned RecoveryUnit, and the OperationContext instance relinquishes + * ownership. Sets the RecoveryUnit to NULL. + * + * Used to transfer ownership of storage engine state from OperationContext + * to ClientCursor for getMore-able queries. + * + * Note that we don't allow the top-level locks to be stored across getMore. + * We rely on active cursors being killed when collections or databases are dropped, + * or when collection metadata changes. + */ + virtual RecoveryUnit* releaseRecoveryUnit() = 0; + + /** + * Associates the OperatingContext with a different RecoveryUnit for getMore or + * subtransactions, see RecoveryUnitSwap. The new state is passed and the old state is + * returned separately even though the state logically belongs to the RecoveryUnit, + * as it is managed by the OperationContext. + */ + virtual RecoveryUnitState setRecoveryUnit(RecoveryUnit* unit, RecoveryUnitState state) = 0; + + /** + * Interface for locking. Caller DOES NOT own pointer. + */ + Locker* lockState() const { + return _locker; + } + + // --- operation level info? --- + + /** + * Raises a UserAssertion if this operation is in a killed state. + */ + virtual void checkForInterrupt() = 0; + + /** + * Returns Status::OK() unless this operation is in a killed state. + */ + virtual Status checkForInterruptNoAssert() = 0; + + /** + * Delegates to CurOp, but is included here to break dependencies. + * Caller does not own the pointer. + * + * Caller must have locked the "Client" associated with this context. + */ + virtual ProgressMeter* setMessage_inlock(const char* msg, + const std::string& name = "Progress", + unsigned long long progressMeterTotal = 0, + int secondsBetween = 3) = 0; + + /** + * Delegates to CurOp, but is included here to break dependencies. + * + * TODO: We return a string because of hopefully transient CurOp thread-unsafe insanity. + */ + virtual std::string getNS() const = 0; + + /** + * Returns the client under which this context runs. + */ + Client* getClient() const; + + virtual uint64_t getRemainingMaxTimeMicros() const = 0; + + /** + * Returns the operation ID associated with this operation. + */ + unsigned int getOpID() const { + return _opId; + } + + /** + * @return true if this instance is primary for this namespace + */ + virtual bool isPrimaryFor(StringData ns) = 0; + + /** + * Returns WriteConcernOptions of the current operation + */ + const WriteConcernOptions& getWriteConcern() const { + return _writeConcern; + } + + void setWriteConcern(const WriteConcernOptions& writeConcern) { + _writeConcern = writeConcern; + } + + /** + * Set whether or not operations should generate oplog entries. + */ + virtual void setReplicatedWrites(bool writesAreReplicated = true) = 0; + + /** + * Returns true if operations should generate oplog entries. + */ + virtual bool writesAreReplicated() const = 0; + + /** + * Marks this operation as killed. + * + * Subsequent calls to checkForInterrupt and checkForInterruptNoAssert by the thread + * executing the operation will indicate that the operation has been killed. + * + * May be called by any thread that has locked the Client owning this operation context, + * or by the thread executing on behalf of this operation context. + */ + void markKilled(); + + /** + * Returns true if markKilled has been called on this operation context. + * + * May be called by any thread that has locked the Client owning this operation context, + * or by the thread executing on behalf of this operation context. + */ + bool isKillPending() const; + +protected: + OperationContext(Client* client, unsigned int opId, Locker* locker); + + RecoveryUnitState _ruState = kNotInUnitOfWork; + +private: + friend class WriteUnitOfWork; + Client* const _client; + const unsigned int _opId; + + // The lifetime of locker is managed by subclasses of OperationContext, so it is not + // safe to access _locker in the destructor of OperationContext. + Locker* const _locker; + + AtomicInt32 _killPending{0}; + WriteConcernOptions _writeConcern; +}; + +class WriteUnitOfWork { + MONGO_DISALLOW_COPYING(WriteUnitOfWork); + +public: + WriteUnitOfWork(OperationContext* txn) + : _txn(txn), + _committed(false), + _toplevel(txn->_ruState == OperationContext::kNotInUnitOfWork) { + _txn->lockState()->beginWriteUnitOfWork(); + if (_toplevel) { + _txn->recoveryUnit()->beginUnitOfWork(_txn); + _txn->_ruState = OperationContext::kActiveUnitOfWork; } + } - void commit() { - invariant(!_committed); - invariant (_txn->_ruState == OperationContext::kActiveUnitOfWork); + ~WriteUnitOfWork() { + if (!_committed) { + invariant(_txn->_ruState != OperationContext::kNotInUnitOfWork); if (_toplevel) { - _txn->recoveryUnit()->commitUnitOfWork(); + _txn->recoveryUnit()->abortUnitOfWork(); _txn->_ruState = OperationContext::kNotInUnitOfWork; + } else { + _txn->_ruState = OperationContext::kFailedUnitOfWork; } _txn->lockState()->endWriteUnitOfWork(); - _committed = true; } + } + + void commit() { + invariant(!_committed); + invariant(_txn->_ruState == OperationContext::kActiveUnitOfWork); + if (_toplevel) { + _txn->recoveryUnit()->commitUnitOfWork(); + _txn->_ruState = OperationContext::kNotInUnitOfWork; + } + _txn->lockState()->endWriteUnitOfWork(); + _committed = true; + } - private: - OperationContext* const _txn; +private: + OperationContext* const _txn; + + bool _committed; + bool _toplevel; +}; - bool _committed; - bool _toplevel; - }; +/** + * RAII-style class to mark the scope of a transaction. ScopedTransactions may be nested. + * An outermost ScopedTransaction calls abandonSnapshot() on destruction, so that the storage + * engine can release resources, such as snapshots or locks, that it may have acquired during + * the transaction. Note that any writes are committed in nested WriteUnitOfWork scopes, + * so write conflicts cannot happen on completing a ScopedTransaction. + * + * TODO: The ScopedTransaction should hold the global lock + */ +class ScopedTransaction { + MONGO_DISALLOW_COPYING(ScopedTransaction); +public: /** - * RAII-style class to mark the scope of a transaction. ScopedTransactions may be nested. - * An outermost ScopedTransaction calls abandonSnapshot() on destruction, so that the storage - * engine can release resources, such as snapshots or locks, that it may have acquired during - * the transaction. Note that any writes are committed in nested WriteUnitOfWork scopes, - * so write conflicts cannot happen on completing a ScopedTransaction. - * - * TODO: The ScopedTransaction should hold the global lock + * The mode for the transaction indicates whether the transaction will write (MODE_IX) or + * only read (MODE_IS), or needs to run without other writers (MODE_S) or any other + * operations (MODE_X) on the server. */ - class ScopedTransaction { - MONGO_DISALLOW_COPYING(ScopedTransaction); - public: - /** - * The mode for the transaction indicates whether the transaction will write (MODE_IX) or - * only read (MODE_IS), or needs to run without other writers (MODE_S) or any other - * operations (MODE_X) on the server. - */ - ScopedTransaction(OperationContext* txn, LockMode mode) : _txn(txn) { } - - ~ScopedTransaction() { - if (!_txn->lockState()->isLocked()) { - _txn->recoveryUnit()->abandonSnapshot(); - } + ScopedTransaction(OperationContext* txn, LockMode mode) : _txn(txn) {} + + ~ScopedTransaction() { + if (!_txn->lockState()->isLocked()) { + _txn->recoveryUnit()->abandonSnapshot(); } + } - private: - OperationContext* _txn; - }; +private: + OperationContext* _txn; +}; } // namespace mongo |