caosdb/transaction.h
Defines
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ASSERT_CAN_ADD_RETRIEVAL
Do all necessary checks and assure that another retrieval (by id or by query) can be added as a sub-request to a transaction.
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ASSERT_CAN_ADD_QUERY
Do all necessary checks and assure that another retrieval (by id or by query) can be added as a sub-request to a transaction.
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ASSERT_CAN_ADD_DELETION
Do all necessary checks and assure that another deletion can be added as a sub-request to a transaction.
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ASSERT_CAN_ADD_INSERTION
Do all necessary checks and assure that another insertion can be added as a sub-request to a transaction.
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ASSERT_CAN_ADD_UPDATE
Do all necessary checks and assure that another update can be added as a sub-request to a transaction.
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namespace caosdb
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namespace transaction
Creation and execution of transactions.
- Author
Timm Fitschen
- Date
2021-08-05
Typedefs
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class Transaction
- #include <transaction.h>
Create a transaction via
CaosDBConnection.createTransaction()Public Types
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enum TransactionType
The transaction type restricts the kind of sub-transaction which may be added to a transaction (insertion, update, deletion, retrieval).
Note
MIXED_READ_AND_WRITE and MIXED_WRITE transaction are not supported yet.
Values:
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enumerator NONE
Unspecified or not specified yet.
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enumerator READ_ONLY
Only retrievals (by id, by query)
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enumerator INSERT_ONLY
Only insertions.
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enumerator UPDATE_ONLY
Only updates.
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enumerator DELETE_ONLY
Only deletions.
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enumerator MIXED_WRITE
Only insertions, deletions, updates.
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enumerator MIXED_READ_AND_WRITE
all kind of transaction.
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enumerator NONE
Public Functions
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~Transaction()
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Transaction(const Transaction&) = delete
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Transaction &operator=(const Transaction&) = delete
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Transaction(Transaction&&) = delete
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Transaction &operator=(Transaction&&) = delete
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auto RetrieveAndDownloadFileById(const std::string &id, const std::string &local_path) noexcept -> StatusCode
Add an entity id to this transaction for retrieval and also download the file.
If the entity doesn’t have a file a warning is appended.
If the file cannot be downloaded due to unsufficient permissions an error is appended.
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auto RetrieveById(const std::string &id) noexcept -> StatusCode
Add an entity id to this transaction for retrieval.
The retrieval is being processed when the Execute() or ExecuteAsynchronously() methods of this transaction are called.
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template<class InputIterator>
inline auto RetrieveById(InputIterator begin, InputIterator end) noexcept -> StatusCode Add all entity ids to this transaction for retrieval.
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auto Query(const std::string &query) noexcept -> StatusCode
Add a query to this transaction.
Currently, only FIND and COUNT queries are supported.
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auto InsertEntity(Entity *entity) noexcept -> StatusCode
Add the entity to this transaction for an insertion.
The insertion is being processed when the Execute() or ExecuteAsynchronously() methods of this transaction are called.
Changing the entity afterwards results in undefined behavior.
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auto UpdateEntity(Entity *entity) noexcept -> StatusCode
Add the entity to this transaction for an update.
The update is being processed when the Execute() or ExecuteAsynchronously() methods of this transaction are called.
Changing the entity afterwards results in undefined behavior.
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auto DeleteById(const std::string &id) noexcept -> StatusCode
Add an entity id to this transaction for deletion.
The deletion is being processed when the Execute() or ExecuteAsynchronously() methods of this transaction are called.
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auto Execute() -> TransactionStatus
Execute this transaction in blocking mode and return the status.
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auto ExecuteAsynchronously() noexcept -> StatusCode
Execute this transaction in non-blocking mode and return immediately.
A client may request the current status at any time via GetStatus().
Use WaitForIt() to join the back-ground execution of this transaction.
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auto WaitForIt() const noexcept -> TransactionStatus
Join the background execution and return the status when the execution terminates.
Use this after ExecuteAsynchronously(), otherwise the TransactionStatus still remains EXECUTING.
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inline auto GetStatus() const noexcept -> TransactionStatus
Return the current status of the transaction.
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inline auto GetResultSet() const noexcept -> const ResultSet&
Return the ResultSet of this transaction.
Note: If this method is called before the transaction has terminated successfully (as indicated by GetStatus().GetCode == 0) this method has undefined behavior.
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inline auto GetResultTable() const noexcept -> const ResultTable&
Return the ResultTable of a SELECT query.
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inline auto ReleaseResultSet() noexcept -> const ResultSet*
Return the ResultSet of this transaction.
This method releases the ResultSet from the transaction leaving it in a currupted state.
This method can be called only once and only after the transaction has terminated.
Otherwise, this method has undefined behavior.
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inline auto GetCountResult() const noexcept -> long
Return the result of a count query
Only meaningful if there was exactly one COUNT query executed in this transaction. In all other cases, the return value will be -1.
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inline auto GetRequestCount() const -> int
Return the number of sub-requests in this transaction.
This is meant for debugging because the number of sub-requests is a GRPC-API detail.
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inline auto ResponseToString() const -> const std::string
Get a JSON representation of the response.
For debugging.
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inline auto RequestToString() const -> const std::string
Get a JSON representation of the request.
For debugging.
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inline auto GetUploadFiles() const -> const std::vector<FileDescriptor>&
Return the vector which holds all the files which are to be uploaded.
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auto Cancel() -> void
Cancel this transaction after it has been started with ExecuteAsynchronously().
This will cancel any active handler and drains the completion_queue.
Protected Functions
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auto ProcessCalls() -> TransactionStatus
Await and process the current handler’s results.
This implies consecutive calls to the handler’s OnNext function.
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inline auto GetArena() const -> Arena*
Return the Arena where this transaction may create Message instances.
Currently, this implementation is only a call to caosdb::utility::get_arena(), but in the future we might want to have a smarter memory management.
Private Functions
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auto ProcessTerminated() const noexcept -> void
Await and process the termination of this transaction.
To be called at the end of DoExecuteTransaction on success.
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auto ProcessRetrieveResponse(RetrieveResponse *retrieve_response, std::vector<std::unique_ptr<Entity>> *entities, bool *set_error) const noexcept -> std::unique_ptr<Entity>
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auto DoExecuteTransaction() noexcept -> void
This functions actually does all the work. Also, it is the one which is going to be send to the background thread by ExecuteAsynchronously.
Private Members
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mutable std::mutex transaction_mutex
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mutable std::future<void> transaction_future
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grpc::CompletionQueue completion_queue
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std::unique_ptr<HandlerInterface> handler_
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std::vector<FileDescriptor> upload_files
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std::map<std::string, FileDescriptor> download_files
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bool has_query = false
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TransactionType transaction_type = TransactionType::NONE
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mutable TransactionStatus status = TransactionStatus::INITIAL()
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std::shared_ptr<EntityTransactionService::Stub> entity_service
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std::shared_ptr<FileTransmissionService::Stub> file_service
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MultiTransactionRequest *request
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mutable MultiTransactionResponse *response
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std::string error_message
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mutable long query_count
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mutable std::unique_ptr<ResultTable> result_table
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enum TransactionType
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namespace transaction