diff options
Diffstat (limited to 'src/mongo/s/write_ops/write_op.h')
| -rw-r--r-- | src/mongo/s/write_ops/write_op.h | 332 |
1 files changed, 161 insertions, 171 deletions
diff --git a/src/mongo/s/write_ops/write_op.h b/src/mongo/s/write_ops/write_op.h index 98ccf0d691d..fb189edfffb 100644 --- a/src/mongo/s/write_ops/write_op.h +++ b/src/mongo/s/write_ops/write_op.h @@ -38,206 +38,196 @@ namespace mongo { - struct TargetedWrite; - struct ChildWriteOp; +struct TargetedWrite; +struct ChildWriteOp; - enum WriteOpState { +enum WriteOpState { - // Item is ready to be targeted - WriteOpState_Ready, + // Item is ready to be targeted + WriteOpState_Ready, - // Item is targeted and we're waiting for outstanding shard requests to populate - // responses - WriteOpState_Pending, + // Item is targeted and we're waiting for outstanding shard requests to populate + // responses + WriteOpState_Pending, - // Op was successful, write completed - // We assume all states higher than this one are *final* - WriteOpState_Completed, + // Op was successful, write completed + // We assume all states higher than this one are *final* + WriteOpState_Completed, - // Op failed with some error - WriteOpState_Error, + // Op failed with some error + WriteOpState_Error, - // Op was cancelled before sending (only child write ops can be cancelled) - WriteOpState_Cancelled, + // Op was cancelled before sending (only child write ops can be cancelled) + WriteOpState_Cancelled, - // Catch-all error state. - WriteOpState_Unknown - }; + // Catch-all error state. + WriteOpState_Unknown +}; + +/** + * State of a single write item in-progress from a client request. + * + * The lifecyle of a write op: + * + * 0. Begins at _Ready, + * + * 1a. Targeted, and a ChildWriteOp created to track the state of each returned TargetedWrite. + * The state is changed to _Pending. + * 1b. If the op cannot be targeted, the error is set directly (_Error), and the write op is + * completed. + * + * 2a. The current TargetedWrites are cancelled, and the op state is reset to _Ready + * 2b. TargetedWrites finish successfully and unsuccessfully. + * + * On the last error arriving... + * + * 3a. If the errors allow for retry, the WriteOp is reset to _Ready, previous ChildWriteOps + * are placed in the history, and goto 0. + * 3b. If the errors don't allow for retry, they are combined into a single error and the + * state is changed to _Error. + * 3c. If there are no errors, the state is changed to _Completed. + * + * WriteOps finish in a _Completed or _Error state. + */ +class WriteOp { +public: + WriteOp(const BatchItemRef& itemRef) : _itemRef(itemRef), _state(WriteOpState_Ready) {} + + ~WriteOp(); /** - * State of a single write item in-progress from a client request. - * - * The lifecyle of a write op: + * Returns the write item for this operation + */ + const BatchItemRef& getWriteItem() const; + + /** + * Returns the op's current state. + */ + WriteOpState getWriteState() const; + + /** + * Returns the op's error. * - * 0. Begins at _Ready, + * Can only be used in state _Error + */ + const WriteErrorDetail& getOpError() const; + + /** + * Creates TargetedWrite operations for every applicable shard, which contain the + * information needed to send the child writes generated from this write item. * - * 1a. Targeted, and a ChildWriteOp created to track the state of each returned TargetedWrite. - * The state is changed to _Pending. - * 1b. If the op cannot be targeted, the error is set directly (_Error), and the write op is - * completed. + * The ShardTargeter determines the ShardEndpoints to send child writes to, but is not + * modified by this operation. * - * 2a. The current TargetedWrites are cancelled, and the op state is reset to _Ready - * 2b. TargetedWrites finish successfully and unsuccessfully. + * Returns !OK if the targeting process itself fails + * (no TargetedWrites will be added, state unchanged) + */ + Status targetWrites(const NSTargeter& targeter, std::vector<TargetedWrite*>* targetedWrites); + + /** + * Returns the number of child writes that were last targeted. + */ + size_t getNumTargeted(); + + /** + * Resets the state of this write op to _Ready and stops waiting for any outstanding + * TargetedWrites. Optional error can be provided for reporting. * - * On the last error arriving... + * Can only be called when state is _Pending, or is a no-op if called when the state + * is still _Ready (and therefore no writes are pending). + */ + void cancelWrites(const WriteErrorDetail* why); + + /** + * Marks the targeted write as finished for this write op. * - * 3a. If the errors allow for retry, the WriteOp is reset to _Ready, previous ChildWriteOps - * are placed in the history, and goto 0. - * 3b. If the errors don't allow for retry, they are combined into a single error and the - * state is changed to _Error. - * 3c. If there are no errors, the state is changed to _Completed. + * One of noteWriteComplete or noteWriteError should be called exactly once for every + * TargetedWrite. + */ + void noteWriteComplete(const TargetedWrite& targetedWrite); + + /** + * Stores the error response of a TargetedWrite for later use, marks the write as finished. * - * WriteOps finish in a _Completed or _Error state. + * As above, one of noteWriteComplete or noteWriteError should be called exactly once for + * every TargetedWrite. */ - class WriteOp { - public: - - WriteOp( const BatchItemRef& itemRef ) : - _itemRef( itemRef ), _state( WriteOpState_Ready ) { - } - - ~WriteOp(); - - /** - * Returns the write item for this operation - */ - const BatchItemRef& getWriteItem() const; - - /** - * Returns the op's current state. - */ - WriteOpState getWriteState() const; - - /** - * Returns the op's error. - * - * Can only be used in state _Error - */ - const WriteErrorDetail& getOpError() const; - - /** - * Creates TargetedWrite operations for every applicable shard, which contain the - * information needed to send the child writes generated from this write item. - * - * The ShardTargeter determines the ShardEndpoints to send child writes to, but is not - * modified by this operation. - * - * Returns !OK if the targeting process itself fails - * (no TargetedWrites will be added, state unchanged) - */ - Status targetWrites( const NSTargeter& targeter, - std::vector<TargetedWrite*>* targetedWrites ); - - /** - * Returns the number of child writes that were last targeted. - */ - size_t getNumTargeted(); - - /** - * Resets the state of this write op to _Ready and stops waiting for any outstanding - * TargetedWrites. Optional error can be provided for reporting. - * - * Can only be called when state is _Pending, or is a no-op if called when the state - * is still _Ready (and therefore no writes are pending). - */ - void cancelWrites( const WriteErrorDetail* why ); - - /** - * Marks the targeted write as finished for this write op. - * - * One of noteWriteComplete or noteWriteError should be called exactly once for every - * TargetedWrite. - */ - void noteWriteComplete( const TargetedWrite& targetedWrite ); - - /** - * Stores the error response of a TargetedWrite for later use, marks the write as finished. - * - * As above, one of noteWriteComplete or noteWriteError should be called exactly once for - * every TargetedWrite. - */ - void noteWriteError( const TargetedWrite& targetedWrite, const WriteErrorDetail& error ); - - /** - * Sets the error for this write op directly, and forces the state to _Error. - * - * Should only be used when in state _Ready. - */ - void setOpError( const WriteErrorDetail& error ); - - private: - - /** - * Updates the op state after new information is received. - */ - void updateOpState(); - - // Owned elsewhere, reference to a batch with a write item - const BatchItemRef _itemRef; - - // What stage of the operation we are at - WriteOpState _state; - - // filled when state == _Pending - std::vector<ChildWriteOp*> _childOps; - - // filled when state == _Error - std::unique_ptr<WriteErrorDetail> _error; - - // Finished child operations, for debugging - std::vector<ChildWriteOp*> _history; - }; + void noteWriteError(const TargetedWrite& targetedWrite, const WriteErrorDetail& error); /** - * State of a write in-progress (to a single shard) which is one part of a larger write - * operation. + * Sets the error for this write op directly, and forces the state to _Error. * - * As above, the write op may finish in either a successful (_Completed) or unsuccessful - * (_Error) state. + * Should only be used when in state _Ready. */ - struct ChildWriteOp { + void setOpError(const WriteErrorDetail& error); - ChildWriteOp( WriteOp* const parent ) : - parentOp( parent ), state( WriteOpState_Ready ), pendingWrite( NULL ) { - } +private: + /** + * Updates the op state after new information is received. + */ + void updateOpState(); - const WriteOp* const parentOp; - WriteOpState state; + // Owned elsewhere, reference to a batch with a write item + const BatchItemRef _itemRef; - // non-zero when state == _Pending - // Not owned here but tracked for reporting - TargetedWrite* pendingWrite; + // What stage of the operation we are at + WriteOpState _state; - // filled when state > _Pending - std::unique_ptr<ShardEndpoint> endpoint; + // filled when state == _Pending + std::vector<ChildWriteOp*> _childOps; - // filled when state == _Error or (optionally) when state == _Cancelled - std::unique_ptr<WriteErrorDetail> error; - }; + // filled when state == _Error + std::unique_ptr<WriteErrorDetail> _error; - // First value is write item index in the batch, second value is child write op index - typedef std::pair<int, int> WriteOpRef; + // Finished child operations, for debugging + std::vector<ChildWriteOp*> _history; +}; - /** - * A write with A) a request targeted at a particular shard endpoint, and B) a response targeted - * at a particular WriteOp. - * - * TargetedWrites are the link between the RPC layer and the in-progress write - * operation. - */ - struct TargetedWrite { +/** + * State of a write in-progress (to a single shard) which is one part of a larger write + * operation. + * + * As above, the write op may finish in either a successful (_Completed) or unsuccessful + * (_Error) state. + */ +struct ChildWriteOp { + ChildWriteOp(WriteOp* const parent) + : parentOp(parent), state(WriteOpState_Ready), pendingWrite(NULL) {} - TargetedWrite( const ShardEndpoint& endpoint, WriteOpRef writeOpRef ) : - endpoint( endpoint ), writeOpRef( writeOpRef ) { - } + const WriteOp* const parentOp; + WriteOpState state; - // Where to send the write - ShardEndpoint endpoint; + // non-zero when state == _Pending + // Not owned here but tracked for reporting + TargetedWrite* pendingWrite; - // Where to find the write item and put the response - // TODO: Could be a more complex handle, shared between write state and networking code if - // we need to be able to cancel ops. - WriteOpRef writeOpRef; - }; + // filled when state > _Pending + std::unique_ptr<ShardEndpoint> endpoint; + // filled when state == _Error or (optionally) when state == _Cancelled + std::unique_ptr<WriteErrorDetail> error; +}; + +// First value is write item index in the batch, second value is child write op index +typedef std::pair<int, int> WriteOpRef; + +/** + * A write with A) a request targeted at a particular shard endpoint, and B) a response targeted + * at a particular WriteOp. + * + * TargetedWrites are the link between the RPC layer and the in-progress write + * operation. + */ +struct TargetedWrite { + TargetedWrite(const ShardEndpoint& endpoint, WriteOpRef writeOpRef) + : endpoint(endpoint), writeOpRef(writeOpRef) {} + + // Where to send the write + ShardEndpoint endpoint; + + // Where to find the write item and put the response + // TODO: Could be a more complex handle, shared between write state and networking code if + // we need to be able to cancel ops. + WriteOpRef writeOpRef; +}; } |