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// Tests that the killCursors command is allowed in transactions.
// @tags: [uses_transactions]
(function() {
"use strict";
const dbName = "test";
const collName = "kill_cursors_in_transaction";
const testDB = db.getSiblingDB(dbName);
const adminDB = db.getSiblingDB("admin");
const session = db.getMongo().startSession({causalConsistency: false});
const sessionDb = session.getDatabase(dbName);
const sessionColl = sessionDb[collName];
sessionColl.drop({writeConcern: {w: "majority"}});
for (let i = 0; i < 4; ++i) {
assert.commandWorked(sessionColl.insert({_id: i}));
}
jsTest.log("Test that the killCursors command is allowed in transactions.");
session.startTransaction();
let res = assert.commandWorked(sessionDb.runCommand({find: collName, batchSize: 2}));
assert(res.hasOwnProperty("cursor"), tojson(res));
assert(res.cursor.hasOwnProperty("id"), tojson(res));
assert.commandWorked(sessionDb.runCommand({killCursors: collName, cursors: [res.cursor.id]}));
assert.commandWorked(session.commitTransaction_forTesting());
jsTest.log("Test that the killCursors cannot be the first operation in a transaction.");
res = assert.commandWorked(sessionDb.runCommand({find: collName, batchSize: 2}));
assert(res.hasOwnProperty("cursor"), tojson(res));
assert(res.cursor.hasOwnProperty("id"), tojson(res));
session.startTransaction();
assert.commandFailedWithCode(
sessionDb.runCommand({killCursors: collName, cursors: [res.cursor.id]}),
ErrorCodes.OperationNotSupportedInTransaction);
assert.commandFailedWithCode(session.abortTransaction_forTesting(), ErrorCodes.NoSuchTransaction);
jsTest.log("killCursors must not block on locks held by the transaction in which it is run.");
session.startTransaction();
// Open a cursor on the collection.
res = assert.commandWorked(sessionDb.runCommand({find: collName, batchSize: 2}));
assert(res.hasOwnProperty("cursor"), tojson(res));
assert(res.cursor.hasOwnProperty("id"), tojson(res));
// Start a drop, which will hang.
let awaitDrop = startParallelShell(function() {
db.getSiblingDB("test")["kill_cursors_in_transaction"].drop({writeConcern: {w: "majority"}});
});
// Wait for the drop to have a pending MODE_X lock on the database.
assert.soon(
function() {
return adminDB
.aggregate([
{$currentOp: {}},
{$match: {"command.drop": collName, waitingForLock: true}}
])
.itcount() === 1;
},
function() {
return "Failed to find drop in currentOp output: " +
tojson(adminDB.aggregate([{$currentOp: {}}]).toArray());
});
// killCursors does not block behind the pending MODE_X lock.
assert.commandWorked(sessionDb.runCommand({killCursors: collName, cursors: [res.cursor.id]}));
assert.commandWorked(session.commitTransaction_forTesting());
// Once the transaction has committed, the drop can proceed.
awaitDrop();
session.endSession();
}());
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