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// Basic integration tests for the background job that periodically kills idle cursors, in both
// mongod and mongos. This test creates the following four cursors:
//
// 1. A no-timeout cursor through mongos.
// 2. A no-timeout cursor through mongod.
// 3. A normal cursor through mongos.
// 4. A normal cursor through mongod.
//
// After a period of inactivity, the test asserts that cursors #1 and #2 are still alive, and that
// #3 and #4 have been killed.
(function() {
'use strict';
// Cursor timeout on mongod is handled by a single thread/timer that will sleep for
// "clientCursorMonitorFrequencySecs" and add the sleep value to each operation's duration when
// it wakes up, timing out those whose "now() - last accessed since" time exceeds. A cursor
// timeout of 5 seconds with a monitor frequency of 1 second means an effective timeout period
// of 4 to 5 seconds.
const mongodCursorTimeoutMs = 5000;
// Cursor timeout on mongos is handled by checking whether the "last accessed" cursor time stamp
// is older than "now() - cursorTimeoutMillis" and is checked every
// "clientCursorMonitorFrequencySecs" by a global thread/timer. A timeout of 4 seconds with a
// monitor frequency of 1 second means an effective timeout period of 4 to 5 seconds.
const mongosCursorTimeoutMs = 4000;
const cursorMonitorFrequencySecs = 1;
const st = new ShardingTest({
shards: 2,
other: {
shardOptions: {
verbose: 1,
setParameter: {
cursorTimeoutMillis: mongodCursorTimeoutMs,
clientCursorMonitorFrequencySecs: cursorMonitorFrequencySecs
}
},
mongosOptions: {
verbose: 1,
setParameter: {
cursorTimeoutMillis: mongosCursorTimeoutMs,
clientCursorMonitorFrequencySecs: cursorMonitorFrequencySecs
}
},
},
enableBalancer: false
});
const adminDB = st.admin;
const routerColl = st.s.getDB('test').user;
const shardHost = st.config.shards.findOne({_id: st.shard1.shardName}).host;
const mongod = new Mongo(shardHost);
const shardColl = mongod.getCollection(routerColl.getFullName());
assert.commandWorked(adminDB.runCommand({enableSharding: routerColl.getDB().getName()}));
st.ensurePrimaryShard(routerColl.getDB().getName(), st.shard0.shardName);
assert.commandWorked(adminDB.runCommand({shardCollection: routerColl.getFullName(), key: {x: 1}}));
assert.commandWorked(adminDB.runCommand({split: routerColl.getFullName(), middle: {x: 10}}));
assert.commandWorked(adminDB.runCommand({
moveChunk: routerColl.getFullName(),
find: {x: 11},
to: st.shard1.shardName,
_waitForDelete: true
}));
for (let x = 0; x < 20; x++) {
assert.writeOK(routerColl.insert({x: x}));
}
// Open both a normal and a no-timeout cursor on mongos. Batch size is 1 to ensure that
// cursor.next() performs only a single operation.
const routerCursorWithTimeout = routerColl.find().batchSize(1);
const routerCursorWithNoTimeout = routerColl.find().batchSize(1);
routerCursorWithNoTimeout.addOption(DBQuery.Option.noTimeout);
// Open both a normal and a no-timeout cursor on mongod. Batch size is 1 to ensure that
// cursor.next() performs only a single operation.
const shardCursorWithTimeout = shardColl.find().batchSize(1);
const shardCursorWithNoTimeout = shardColl.find().batchSize(1);
shardCursorWithNoTimeout.addOption(DBQuery.Option.noTimeout);
// Execute initial find on each cursor.
routerCursorWithTimeout.next();
routerCursorWithNoTimeout.next();
shardCursorWithTimeout.next();
shardCursorWithNoTimeout.next();
// Wait until the idle cursor background job has killed the cursors that do not have the "no
// timeout" flag set. We use the "cursorTimeoutMillis" and "clientCursorMonitorFrequencySecs"
// setParameters above to reduce the amount of time we need to wait here.
assert.soon(function() {
return routerColl.getDB().serverStatus().metrics.cursor.timedOut > 0;
}, "sharded cursor failed to time out");
// Wait for the shard to have two open cursors on it (routerCursorWithNoTimeout and
// shardCursorWithNoTimeout).
// We cannot reliably use metrics.cursor.timedOut here, because this will be 2 if
// routerCursorWithTimeout is killed for timing out on the shard, and 1 if
// routerCursorWithTimeout is killed by a killCursors command from the mongos.
assert.soon(function() {
return shardColl.getDB().serverStatus().metrics.cursor.open.total == 2;
}, "cursor failed to time out");
assert.throws(function() {
routerCursorWithTimeout.itcount();
});
assert.throws(function() {
shardCursorWithTimeout.itcount();
});
// +1 because we already advanced once
assert.eq(routerColl.count(), routerCursorWithNoTimeout.itcount() + 1);
assert.eq(shardColl.count(), shardCursorWithNoTimeout.itcount() + 1);
st.stop();
})();
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