/* * Test linearizability of getMore on a cursor. */ ( function () { 'use strict' ;   var num_nodes = 3; var name = 'linearizable_read_concern' ; var replTest = new ReplSetTest({name: name, nodes: num_nodes, useBridge: true }); var config = replTest.getReplSetConfig();   // Increased election timeout to avoid having the primary step down while we are // testing linearizable functionality on an isolated primary. config.settings = {electionTimeoutMillis: 20000};   replTest.startSet(); replTest.initiate(config); replTest.awaitReplication(); var primary = replTest.getPrimary(); var secondaries = replTest.getSecondaries();   // Do a write on the original primary. assert.writeOK( primary.getDB( "test" ).foo.insert({_id: 0, x: 0}, { "writeConcern" : { "w" : "majority" }})); primary = replTest.getPrimary();   // Open a cursor on the original primary at 'linearizable' read concern. let result = primary.getDB( "test" ).runCommand( { "find" : "foo" , filter: {_id: 0}, "readConcern" : {level: "linearizable" }, batchSize: 0}); assert.commandWorked(result); let cursorId = result.cursor.id;   jsTestLog( "Setting up partitions such that the primary is isolated: [Secondary-Secondary] [Primary]" ); secondaries[0].disconnect(primary); secondaries[1].disconnect(primary);   jsTestLog( "Step up a new primary, and wait until it can accept writes." ); assert.commandWorked(secondaries[0].adminCommand({replSetStepUp: 1})); assert.soonNoExcept( function () { return secondaries[0].adminCommand({isMaster: 1}).ismaster; }); let newPrimary = secondaries[0]; jsTestLog( "New node " + newPrimary + " should now be primary" );   jsTestLog( "Do a majority write to the new primary." ); assert.writeOK(newPrimary.getDB( "test" ).foo.update( {_id: 0}, {$set: {x: 1}}, { "writeConcern" : { "w" : "majority" }}));   jsTestLog( "Do a linearizable read on the new primary." ); result = newPrimary.getDB( "test" ).runCommand( { "find" : "foo" , filter: {_id: 0}, "readConcern" : {level: "linearizable" }, batchSize: 1}); assert.commandWorked(result); // A linearizable read should return the effects of the most recent majority committed write. assert.docEq([{_id: 0, x: 1}], result.cursor.firstBatch);   jsTestLog( "Do a linearizable getMore read on the old primary." ); result = primary.getDB( "test" ).runCommand({ "getMore" : cursorId, collection: "foo" , batchSize: 1}); assert.commandWorked(result); // A linearizable read should return the effects of the most recent majority committed write // (this should fail if getMores do not uphold linearizability guarantee correctly). assert.docEq([{_id: 0, x: 1}], result.cursor.nextBatch);   // Re-connect and shut down. secondaries[0].reconnect(primary); secondaries[1].reconnect(primary); replTest.stopSet(); }());