SERVER-24239 shardCollection should use simple collation when creating shard key index

4 files changed, 59 insertions, 14 deletions

diff --git a/jstests/sharding/shard_collection_basic.js b/jstests/sharding/shard_collection_basic.js
index 0b99055ed6c..def763969c7 100644
--- a/jstests/sharding/shard_collection_basic.js
+++ b/jstests/sharding/shard_collection_basic.js
@@ -44,6 +44,14 @@
         mongos.getDB(kDbName).dropDatabase();
     }
 
+    function getIndexSpecByName(coll, indexName) {
+        var indexes = coll.getIndexes().filter(function(spec) {
+            return spec.name === indexName;
+        });
+        assert.eq(1, indexes.length, 'index "' + indexName + '" not found"');
+        return indexes[0];
+    }
+
     // Fail if db is not sharded.
     assert.commandFailed(mongos.adminCommand({shardCollection: kDbName + '.foo', key: {_id: 1}}));
 
@@ -179,17 +187,40 @@
     mongos.getDB(kDbName).foo.drop();
     assert.commandWorked(
         mongos.getDB(kDbName).createCollection('foo', {collation: {locale: 'en_US'}}));
-    assert.commandFailed(mongos.adminCommand({shardCollection: kDbName + '.foo', key: {_id: 1}}));
+    assert.commandFailed(mongos.adminCommand({shardCollection: kDbName + '.foo', key: {a: 1}}));
+
+    // shardCollection should fail for the key pattern {_id: 1} if the collection has a non-simple
+    // default collation.
+    mongos.getDB(kDbName).foo.drop();
+    assert.commandWorked(
+        mongos.getDB(kDbName).createCollection('foo', {collation: {locale: 'en_US'}}));
+    assert.commandFailed(mongos.adminCommand(
+        {shardCollection: kDbName + '.foo', key: {_id: 1}, collation: {locale: 'simple'}}));
 
-    // TODO SERVER-24239:
-    // Test that shardCollection for the key pattern {_id: 1} fails if there is a non-simple
-    // collection default collation.
-    // Test that shardCollection for the key pattern {a: 1} fails if there is already an index 'a_1'
+    // shardCollection should fail for the key pattern {a: 1} if there is already an index 'a_1',
     // but it has a non-simple collation.
-    // Test that shardCollection for the key pattern {a: 1} and collation {locale: 'simple'}
-    // succeeds if there is no index 'a_1', but there is a non-simple collection default collation.
-    // Test that shardCollection for the key pattern {a: 1} and collation {locale: 'simple'}
-    // succeeds if there are two indexes on {a: 1} and one has the simple collation.
+    mongos.getDB(kDbName).foo.drop();
+    assert.commandWorked(
+        mongos.getDB(kDbName).foo.createIndex({a: 1}, {collation: {locale: 'en_US'}}));
+    assert.commandFailed(mongos.adminCommand({shardCollection: kDbName + '.foo', key: {a: 1}}));
+
+    // shardCollection should succeed for the key pattern {a: 1} and collation {locale: 'simple'} if
+    // there is no index 'a_1', but there is a non-simple collection default collation.
+    mongos.getDB(kDbName).foo.drop();
+    assert.commandWorked(
+        mongos.getDB(kDbName).createCollection('foo', {collation: {locale: 'en_US'}}));
+    assert.commandWorked(mongos.adminCommand(
+        {shardCollection: kDbName + '.foo', key: {a: 1}, collation: {locale: 'simple'}}));
+    var indexSpec = getIndexSpecByName(mongos.getDB(kDbName).foo, 'a_1');
+    assert(!indexSpec.hasOwnProperty('collation'));
+
+    // shardCollection should succeed for the key pattern {a: 1} if there are two indexes on {a: 1}
+    // and one has the simple collation.
+    mongos.getDB(kDbName).foo.drop();
+    assert.commandWorked(mongos.getDB(kDbName).foo.createIndex({a: 1}, {name: "a_1_simple"}));
+    assert.commandWorked(mongos.getDB(kDbName).foo.createIndex(
+        {a: 1}, {collation: {locale: 'en_US'}, name: "a_1_en_US"}));
+    assert.commandWorked(mongos.adminCommand({shardCollection: kDbName + '.foo', key: {a: 1}}));
 
     // shardCollection should fail on a non-empty collection when the only index available with the
     // shard key as a prefix has a non-simple collation.
diff --git a/src/mongo/s/cluster_write.cpp b/src/mongo/s/cluster_write.cpp
index c6e92ea4583..c45fffbf1ec 100644
--- a/src/mongo/s/cluster_write.cpp
+++ b/src/mongo/s/cluster_write.cpp
@@ -65,7 +65,10 @@ namespace {
  * Constructs the BSON specification document for the given namespace, index key
  * and options.
  */
-BSONObj createIndexDoc(const string& ns, const BSONObj& keys, bool unique) {
+BSONObj createIndexDoc(const string& ns,
+                       const BSONObj& keys,
+                       const BSONObj& collation,
+                       bool unique) {
     BSONObjBuilder indexDoc;
     indexDoc.append("ns", ns);
     indexDoc.append("key", keys);
@@ -92,6 +95,10 @@ BSONObj createIndexDoc(const string& ns, const BSONObj& keys, bool unique) {
 
     indexDoc.append("name", indexName.str());
 
+    if (!collation.isEmpty()) {
+        indexDoc.append("collation", collation);
+    }
+
     if (unique) {
         indexDoc.appendBool("unique", unique);
     }
@@ -146,11 +153,12 @@ void splitIfNeeded(OperationContext* txn, const NamespaceString& nss, const Targ
 
 }  // namespace
 
-Status clusterCreateIndex(OperationContext* txn, const string& ns, BSONObj keys, bool unique) {
+Status clusterCreateIndex(
+    OperationContext* txn, const string& ns, BSONObj keys, BSONObj collation, bool unique) {
     const NamespaceString nss(ns);
     const std::string dbName = nss.db().toString();
 
-    BSONObj indexDoc = createIndexDoc(ns, keys, unique);
+    BSONObj indexDoc = createIndexDoc(ns, keys, collation, unique);
 
     // Go through the shard insert path
     std::unique_ptr<BatchedInsertRequest> insert(new BatchedInsertRequest());
diff --git a/src/mongo/s/cluster_write.h b/src/mongo/s/cluster_write.h
index 0af9615a47c..a0d5e931104 100644
--- a/src/mongo/s/cluster_write.h
+++ b/src/mongo/s/cluster_write.h
@@ -56,6 +56,7 @@ private:
 /**
  * Used only for writes to the config server, config and admin databases.
  */
-Status clusterCreateIndex(OperationContext* txn, const std::string& ns, BSONObj keys, bool unique);
+Status clusterCreateIndex(
+    OperationContext* txn, const std::string& ns, BSONObj keys, BSONObj collation, bool unique);
 
 }  // namespace mongo
diff --git a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
index 25d74323b5c..6b8eeb654db 100644
--- a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
+++ b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
@@ -400,7 +400,12 @@ public:
             // 5. If no useful index exists, and collection empty, create one on proposedKey.
             //    Only need to call ensureIndex on primary shard, since indexes get copied to
             //    receiving shard whenever a migrate occurs.
-            Status status = clusterCreateIndex(txn, nss.ns(), proposedKey, careAboutUnique);
+            Status status = clusterCreateIndex(
+                txn,
+                nss.ns(),
+                proposedKey,
+                BSON(CollationSpec::kLocaleField << CollationSpec::kSimpleBinaryComparison),
+                careAboutUnique);
             if (!status.isOK()) {
                 errmsg = str::stream() << "ensureIndex failed to create index on "
                                        << "primary shard: " << status.reason();