// Documents containing the min value of a moveChunk will // get lost on a chunk migration. import {ShardingTest} from "jstests/libs/shardingtest.js" ; let s = new ShardingTest({name: "experimentColl" , shards: 2, mongos: 1}); let shardedDb = s.getDB( "test" ); assert (s.adminCommand({enablesharding: "test" , primaryShard: s.shard1.shardName})); const experimentColl = shardedDb.experimentColl; assert (experimentColl.drop()) assert .commandWorked(experimentColl.insert([ { "_id" : 0, "a" : 0, "b" : 0 }, { "_id" : 1, "a" : 0, "b" : 10 }, { "_id" : 2, "a" : 0, "b" : -10 } ])) // We should have 3 documents const resultsBeforeSharding = experimentColl.aggregate([]).toArray(); assert .eq(resultsBeforeSharding.length, 3) // Shard with a wildcard component in the index // Another index that repros the issue is {b: 1, '$**' : -1} with {wildcardProjection: {a: 1}} assert .commandWorked(experimentColl.createIndex({b: 1, 'a.$**' : -1})); assert (s.adminCommand({shardcollection: "test.experimentColl" , key: {b: 1}})); // Now split the and move the data between the shards assert (s.adminCommand({split: "test.experimentColl" , middle: {b: 0}})); assert (s.adminCommand({ moveChunk: "test.experimentColl" , find: {b: 1}, to: s.getOther(s.getPrimaryShard( "test" )).name, _waitForDelete: true })); const results = experimentColl.aggregate([]).toArray() assert .eq(results.length, 3); // finds 2 documents instead of 3 s.stop(); // Documents that don't contain the shardKey may get // lost due to chunk migrations. import {ShardingTest} from "jstests/libs/shardingtest.js" ; let s = new ShardingTest({name: "experimentColl" , shards: 2, mongos: 1}); let shardedDb = s.getDB( "test" ); assert (s.adminCommand({enablesharding: "test" , primaryShard: s.shard0.shardName})); const experimentColl = shardedDb.experimentColl; assert (experimentColl.drop()) assert .commandWorked( experimentColl.insert([{ "_id" : 0, "x" : 0}, { "_id" : 1, "b" : 10}, { "_id" : 2, "b" : -10}])) // We should have 3 documents const resultsBeforeSharding = experimentColl.aggregate([]).toArray(); assert .eq(resultsBeforeSharding.length, 3) // Shard with a wildcard component in the index assert .commandWorked(experimentColl.createIndex({b: 1, 'a.$**' : 1})); assert (s.adminCommand({shardcollection: "test.experimentColl" , key: {b: 1}})); assert (s.adminCommand({ moveRange: "test.experimentColl" , min: {b: MinKey}, max: {b: MaxKey}, toShard: s.shard1.shardName, })); const results = experimentColl.aggregate([]).toArray() assert .eq(results.length, 3); // finds 2 documents instead of 3 s.stop();