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/**
* Test the balancerCollectionStatus command and its possible outputs
*/
(function() {
'use strict';
const chunkSizeMB = 1;
let st = new ShardingTest({
shards: 3,
other: {
// Set global max chunk size to 1MB
chunkSize: chunkSizeMB
}
});
function runBalancer(rounds) {
st.startBalancer();
let numRounds = 0;
// Let the balancer run for caller specified number of rounds.
assert.soon(() => {
st.awaitBalancerRound();
st.printShardingStatus(true);
numRounds++;
return (numRounds === rounds);
}, 'Balancer failed to run for ' + rounds + ' rounds', 1000 * 60 * (3 * rounds));
st.stopBalancer();
}
// only fully quilified namespaces are allowed on the command
assert.commandFailedWithCode(st.s0.adminCommand({balancerCollectionStatus: 'db'}),
ErrorCodes.InvalidNamespace);
// only sharded databases are allowed
assert.commandFailedWithCode(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}),
ErrorCodes.NamespaceNotSharded);
// setup the collection for the test
assert.commandWorked(st.s0.adminCommand({enableSharding: 'db'}));
assert.commandWorked(st.s0.adminCommand({shardCollection: 'db.col', key: {key: 1}}));
// only sharded collections are allowed
assert.commandWorked(st.s0.getDB('db').runCommand({create: "col2"}));
assert.commandFailedWithCode(st.s0.adminCommand({balancerCollectionStatus: 'db.col2'}),
ErrorCodes.NamespaceNotSharded);
let result = assert.commandWorked(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}));
// new collections must be balanced
assert.eq(result.balancerCompliant, true);
// get shardIds
const shards = st.s0.getDB('config').shards.find().toArray();
// manually split and place the 3 chunks on the same shard
assert.commandWorked(st.s0.adminCommand({split: 'db.col', middle: {key: 10}}));
assert.commandWorked(st.s0.adminCommand({split: 'db.col', middle: {key: 20}}));
assert.commandWorked(st.s0.adminCommand({moveChunk: 'db.col', find: {key: 0}, to: shards[0]._id}));
assert.commandWorked(st.s0.adminCommand({moveChunk: 'db.col', find: {key: 10}, to: shards[0]._id}));
assert.commandWorked(st.s0.adminCommand({moveChunk: 'db.col', find: {key: 20}, to: shards[0]._id}));
// check the current status
result = assert.commandWorked(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}));
// chunksImbalanced expected
assert.eq(result.balancerCompliant, false);
assert.eq(result.firstComplianceViolation, 'chunksImbalance');
// run balancer with 3 rounds
runBalancer(3);
// the chunks must be balanced now
result = assert.commandWorked(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}));
assert.eq(result.balancerCompliant, true);
// manually move a chunk to a shard before creating zones (this will help
// testing the zone violation)
assert.commandWorked(st.s0.adminCommand({moveChunk: 'db.col', find: {key: 10}, to: shards[2]._id}));
// create zones on first two shards only
assert.commandWorked(st.s0.adminCommand({addShardToZone: shards[0]._id, zone: 'zone0'}));
assert.commandWorked(st.s0.adminCommand(
{updateZoneKeyRange: 'db.col', min: {key: MinKey}, max: {key: 10}, zone: 'zone0'}));
assert.commandWorked(st.s0.adminCommand({addShardToZone: shards[1]._id, zone: 'zone1'}));
assert.commandWorked(st.s0.adminCommand(
{updateZoneKeyRange: 'db.col', min: {key: 10}, max: {key: 20}, zone: 'zone1'}));
result = assert.commandWorked(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}));
// having a chunk on a different zone will cause a zone violation
assert.eq(result.balancerCompliant, false);
assert.eq(result.firstComplianceViolation, 'zoneViolation');
// run balancer, we don't know exactly where the first run moved the chunks
// so lets run 3 rounds just in case
runBalancer(3);
// the chunks must be balanced now
result = assert.commandWorked(st.s0.adminCommand({balancerCollectionStatus: 'db.col'}));
// All chunks are balanced and in the correct zone
assert.eq(result.balancerCompliant, true);
const configDB = st.configRS.getPrimary().getDB('config');
const fcvDoc = configDB.adminCommand({getParameter: 1, featureCompatibilityVersion: 1});
if (MongoRunner.compareBinVersions(fcvDoc.featureCompatibilityVersion.version, '5.3') >= 0) {
// Ensure that the expected chunk size is part of the response.
assert.eq(result.chunkSize, chunkSizeMB);
}
st.stop();
})();
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