SERVER-63732 Add new implicitlyCreateIndex and enforceUniqueness to shardCollection command

8 files changed, 57 insertions, 13 deletions

diff --git a/src/mongo/db/s/config/configsvr_refine_collection_shard_key_command.cpp b/src/mongo/db/s/config/configsvr_refine_collection_shard_key_command.cpp
index a58168f06be..28bdc7869df 100644
--- a/src/mongo/db/s/config/configsvr_refine_collection_shard_key_command.cpp
+++ b/src/mongo/db/s/config/configsvr_refine_collection_shard_key_command.cpp
@@ -128,6 +128,7 @@ public:
                                       newShardKeyPattern,
                                       boost::none,
                                       collType.getUnique(),
+                                      true /* enforceUniquenessCheck */,
                                       shardkeyutil::ValidationBehaviorsRefineShardKey(opCtx, nss));
                               });
 
diff --git a/src/mongo/db/s/create_collection_coordinator.cpp b/src/mongo/db/s/create_collection_coordinator.cpp
index 76122d24165..eaf25a98659 100644
--- a/src/mongo/db/s/create_collection_coordinator.cpp
+++ b/src/mongo/db/s/create_collection_coordinator.cpp
@@ -759,13 +759,27 @@ void CreateCollectionCoordinator::_createCollectionAndIndexes(OperationContext*
 
     shardkeyutil::validateShardKeyIsNotEncrypted(opCtx, nss(), *_shardKeyPattern);
 
-    const auto indexCreated = shardkeyutil::validateShardKeyIndexExistsOrCreateIfPossible(
-        opCtx,
-        nss(),
-        *_shardKeyPattern,
-        _collationBSON,
-        _doc.getUnique().value_or(false),
-        shardkeyutil::ValidationBehaviorsShardCollection(opCtx));
+    auto indexCreated = false;
+    if (_doc.getImplicitlyCreateIndex()) {
+        indexCreated = shardkeyutil::validateShardKeyIndexExistsOrCreateIfPossible(
+            opCtx,
+            nss(),
+            *_shardKeyPattern,
+            _collationBSON,
+            _doc.getUnique().value_or(false),
+            _doc.getEnforceUniquenessCheck(),
+            shardkeyutil::ValidationBehaviorsShardCollection(opCtx));
+    } else {
+        uassert(6373200,
+                "Must have an index compatible with the proposed shard key",
+                validShardKeyIndexExists(opCtx,
+                                         nss(),
+                                         *_shardKeyPattern,
+                                         _collationBSON,
+                                         _doc.getUnique().value_or(false) &&
+                                             _doc.getEnforceUniquenessCheck(),
+                                         shardkeyutil::ValidationBehaviorsShardCollection(opCtx)));
+    }
 
     auto replClientInfo = repl::ReplClientInfo::forClient(opCtx->getClient());
 
diff --git a/src/mongo/db/s/resharding/resharding_recipient_service.cpp b/src/mongo/db/s/resharding/resharding_recipient_service.cpp
index 2af2050a1f3..a6d35892ee9 100644
--- a/src/mongo/db/s/resharding/resharding_recipient_service.cpp
+++ b/src/mongo/db/s/resharding/resharding_recipient_service.cpp
@@ -532,6 +532,7 @@ void ReshardingRecipientService::RecipientStateMachine::
                     ShardKeyPattern{_metadata.getReshardingKey()},
                     CollationSpec::kSimpleSpec,
                     false /* unique */,
+                    true /* enforceUniquenessCheck */,
                     shardkeyutil::ValidationBehaviorsShardCollection(opCtx.get()));
             });
     }
diff --git a/src/mongo/db/s/shard_key_util.cpp b/src/mongo/db/s/shard_key_util.cpp
index d263712fa91..2a081555d0e 100644
--- a/src/mongo/db/s/shard_key_util.cpp
+++ b/src/mongo/db/s/shard_key_util.cpp
@@ -106,7 +106,7 @@ bool validShardKeyIndexExists(OperationContext* opCtx,
                               const NamespaceString& nss,
                               const ShardKeyPattern& shardKeyPattern,
                               const boost::optional<BSONObj>& defaultCollation,
-                              bool unique,
+                              bool requiresUnique,
                               const ShardKeyValidationBehaviors& behaviors) {
     auto indexes = behaviors.loadIndexes(nss);
 
@@ -146,7 +146,7 @@ bool validShardKeyIndexExists(OperationContext* opCtx,
     }
 
     // 3. If proposed key is required to be unique, additionally check for exact match.
-    if (hasUsefulIndexForKey && unique) {
+    if (hasUsefulIndexForKey && requiresUnique) {
         BSONObj eqQuery = BSON("ns" << nss.ns() << "key" << shardKeyPattern.toBSON());
         BSONObj eqQueryResult;
 
@@ -186,13 +186,17 @@ bool validateShardKeyIndexExistsOrCreateIfPossible(OperationContext* opCtx,
                                                    const ShardKeyPattern& shardKeyPattern,
                                                    const boost::optional<BSONObj>& defaultCollation,
                                                    bool unique,
+                                                   bool enforceUniquenessCheck,
                                                    const ShardKeyValidationBehaviors& behaviors) {
-    if (validShardKeyIndexExists(
-            opCtx, nss, shardKeyPattern, defaultCollation, unique, behaviors)) {
+    if (validShardKeyIndexExists(opCtx,
+                                 nss,
+                                 shardKeyPattern,
+                                 defaultCollation,
+                                 unique && enforceUniquenessCheck,
+                                 behaviors)) {
         return false;
     }
 
-
     // 4. If no useful index, verify we can create one.
     behaviors.verifyCanCreateShardKeyIndex(nss);
 
diff --git a/src/mongo/db/s/shard_key_util.h b/src/mongo/db/s/shard_key_util.h
index dd5363df700..5d20a013bef 100644
--- a/src/mongo/db/s/shard_key_util.h
+++ b/src/mongo/db/s/shard_key_util.h
@@ -150,6 +150,7 @@ bool validateShardKeyIndexExistsOrCreateIfPossible(OperationContext* opCtx,
                                                    const ShardKeyPattern& shardKeyPattern,
                                                    const boost::optional<BSONObj>& defaultCollation,
                                                    bool unique,
+                                                   bool enforceUniquenessCheck,
                                                    const ShardKeyValidationBehaviors& behaviors);
 /**
  * Compares the proposed shard key with the collection's existing indexes to ensure they are a legal
@@ -163,7 +164,7 @@ bool validShardKeyIndexExists(OperationContext* opCtx,
                               const NamespaceString& nss,
                               const ShardKeyPattern& shardKeyPattern,
                               const boost::optional<BSONObj>& defaultCollation,
-                              bool unique,
+                              bool requiresUnique,
                               const ShardKeyValidationBehaviors& behaviors);
 
 void validateShardKeyIsNotEncrypted(OperationContext* opCtx,
diff --git a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
index 68ec95bb05c..6624a1ec2bc 100644
--- a/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
+++ b/src/mongo/s/commands/cluster_shard_collection_cmd.cpp
@@ -102,6 +102,8 @@ public:
         requestParamsObj.setCollation(shardCollRequest.getCollation());
         requestParamsObj.setTimeseries(shardCollRequest.getTimeseries());
         requestParamsObj.setCollectionUUID(shardCollRequest.getCollectionUUID());
+        requestParamsObj.setImplicitlyCreateIndex(shardCollRequest.getImplicitlyCreateIndex());
+        requestParamsObj.setEnforceUniquenessCheck(shardCollRequest.getEnforceUniquenessCheck());
         shardsvrCollRequest.setCreateCollectionRequest(std::move(requestParamsObj));
         shardsvrCollRequest.setDbName(nss.db());
 
diff --git a/src/mongo/s/commands/shard_collection.idl b/src/mongo/s/commands/shard_collection.idl
index 005aa90c1b9..82ea915656a 100644
--- a/src/mongo/s/commands/shard_collection.idl
+++ b/src/mongo/s/commands/shard_collection.idl
@@ -78,3 +78,13 @@ structs:
         description: "The expected UUID of the collection."
         type: uuid
         optional: true
+      implicitlyCreateIndex:
+        description: "Creates an index on the shard key pattern if the collection is empty."
+        type: bool
+        default: true
+      enforceUniquenessCheck:
+        description: >-
+          Controls whether this command verifies that any unique indexes are prefixed by the shard
+          key pattern if unique is true. If true then it will verify and if false then it won't.
+        type: bool
+        default: true
diff --git a/src/mongo/s/request_types/sharded_ddl_commands.idl b/src/mongo/s/request_types/sharded_ddl_commands.idl
index 9bd7602a7dc..bd20052c334 100644
--- a/src/mongo/s/request_types/sharded_ddl_commands.idl
+++ b/src/mongo/s/request_types/sharded_ddl_commands.idl
@@ -154,6 +154,17 @@ structs:
                 type: uuid
                 description: "The expected UUID of the collection."
                 optional: true
+            implicitlyCreateIndex:
+                description: "Creates an index on the shard key pattern if the collection is empty."
+                type: bool
+                default: true
+            enforceUniquenessCheck:
+                description: >-
+                    Controls whether this command verifies that any unique indexes are prefixed by
+                    the shard key pattern if unique is true. If true then it will verify and if
+                    false then it won't.
+                type: bool
+                default: true
 
     CreateCollectionResponse:
         description: "Response of the create collection command"