-
Type: Task
-
Resolution: Fixed
-
Priority: Major - P3
-
Affects Version/s: None
-
Component/s: Documentation
-
None
Hi –
for the manual – would like to pop in driver examples in
Drivers section and Retry section
If we could get the corresponding driver examples.
- The Intro example will be for the Drivers section – where it's to highlight – how to use a transaction, and the section will be emphasizing the passing of the session to the operations in the txn.
- The retry examples will of course be in the retry section.
// Start Transactions Intro Example 1 function updateEmployeeInfo(session) { employeesCollection = session.getDatabase("hr").employees; eventsCollection = session.getDatabase("reporting").events; session.startTransaction( { readConcern: { level: "snapshot" }, writeConcern: { w: "majority" } } ); try{ employeesCollection.updateOne( { employee: 3 }, { $set: { status: "Inactive" } } ); eventsCollection.insertOne( { employee: 3, status: { new: "Inactive", old: "Active" } } ); } catch (error) { print("Caught exception during transaction, aborting."); session.abortTransaction(); throw error; } while (true) { try { session.commitTransaction(); // Uses write concern set at transaction start. print("Transaction committed."); break; } catch (error) { // Can retry commit if (error.hasOwnProperty("errorLabels") && error.errorLabels.includes("UnknownTransactionCommitResult") ) { print("UnknownTransactionCommitResult, retrying commit operation ..."); continue; } else { print("Error during commit ..."); throw error; } } } } // End Transactions Intro Example 1 // Start Transactions Retry Example 1 function runTransactionWithRetry(txnFunc, session) { while (true) { try { txnFunc(session); // performs transaction break; } catch (error) { print("Transaction aborted. Caught exception during transaction."); // If transient error, retry the whole transaction if ( error.hasOwnProperty("errorLabels") && error.errorLabels.includes( "TransientTransactionError") ) { print("TransientTransactionError, retrying transaction ..."); continue; } else { throw error; } } } } // End Transactions Retry Example 1 // Start Transactions Retry Example 2 function commitWithRetry(session) { while (true) { try { session.commitTransaction(); // Uses write concern set at transaction start. print("Transaction committed."); break; } catch (error) { // Can retry commit if (error.hasOwnProperty("errorLabels") && error.errorLabels.includes( "UnknownTransactionCommitResult") ) { print("UnknownTransactionCommitResult, retrying commit operation ..."); continue; } else { print("Error during commit ..."); throw error; } } } } // End Transactions Retry Example 2 // Start Transactions Retry Example 3 function runTransactionWithRetry(txnFunc, session) { while (true) { try { txnFunc(session); // performs transaction break; } catch (error) { // If transient error, retry the whole transaction if ( error.hasOwnProperty("errorLabels") && error.errorLabels.includes("TransientTransactionError") ) { print("TransientTransactionError, retrying transaction ..."); continue; } else { throw error; } } } } function commitWithRetry(session) { while (true) { try { session.commitTransaction(); // Uses write concern set at transaction start. print("Transaction committed."); break; } catch (error) { // Can retry commit if (error.hasOwnProperty("errorLabels") && error.errorLabels.includes("UnknownTransactionCommitResult") ) { print("UnknownTransactionCommitResult, retrying commit operation ..."); continue; } else { print("Error during commit ..."); throw error; } } } } // Updates two collections in a transactions function updateEmployeeInfo(session) { employeesCollection = session.getDatabase("hr").employees; eventsCollection = session.getDatabase("reporting").events; session.startTransaction( { readConcern: { level: "snapshot" }, writeConcern: { w: "majority" } } ); try{ employeesCollection.updateOne( { employee: 3 }, { $set: { status: "Inactive" } } ); eventsCollection.insertOne( { employee: 3, status: { new: "Inactive", old: "Active" } } ); } catch (error) { print("Caught exception during transaction, aborting."); session.abortTransaction(); throw error; } commitWithRetry(session); } // Start a session. session = db.getMongo("myRepl/mongodb0.example.net:27017,mongodb1.example.net:27017,mongodb2.example.net:27017").startSession( { mode: "primary" } ); try{ runTransactionWithRetry(updateEmployeeInfo, session); } catch (error) { // Do something with error } finally { session.endSession(); } // End Transactions Retry Example 3
- is depended on by
-
DRIVERS-488 Provide Transactions example for Docs
- Closed