SERVER-62906 Add a check in the createCollection/shardCollection path verifying the collection name length

4 files changed, 27 insertions, 0 deletions

diff --git a/jstests/sharding/shard_collection_basic.js b/jstests/sharding/shard_collection_basic.js
index 445dab8a2e7..877df390af6 100644
--- a/jstests/sharding/shard_collection_basic.js
+++ b/jstests/sharding/shard_collection_basic.js
@@ -67,6 +67,19 @@ assert.commandFailed(mongos.adminCommand({shardCollection: 'foo', key: {_id: 1}}
 
 assert.commandFailed(mongos.adminCommand({shardCollection: 'foo', key: "aaa"}));
 
+// Verify namespace length limit.
+const testDB = st.rs0.getPrimary().getDB(kDbName);
+const fcvDoc = testDB.adminCommand({getParameter: 1, featureCompatibilityVersion: 1});
+if (MongoRunner.compareBinVersions(fcvDoc.featureCompatibilityVersion.version, '4.4') >= 0) {
+    const longEnoughNs = kDbName + '.' +
+        'x'.repeat(235 - kDbName.length - 1);
+    assert.commandWorked(mongos.adminCommand({shardCollection: longEnoughNs, key: {_id: 1}}));
+
+    const tooLongNs = longEnoughNs + 'x';
+    assert.commandFailedWithCode(mongos.adminCommand({shardCollection: tooLongNs, key: {_id: 1}}),
+                                 ErrorCodes.InvalidNamespace);
+}
+
 // shardCollection may only be run against admin database.
 assert.commandFailed(
     mongos.getDB('test').runCommand({shardCollection: kDbName + '.foo', key: {_id: 1}}));
diff --git a/src/mongo/db/namespace_string.h b/src/mongo/db/namespace_string.h
index 2d549b1d1f7..8a9b62844d7 100644
--- a/src/mongo/db/namespace_string.h
+++ b/src/mongo/db/namespace_string.h
@@ -51,6 +51,11 @@ public:
     constexpr static size_t MaxNSCollectionLenFCV42 = 120U;
     constexpr static size_t MaxNsCollectionLen = 255;
 
+    // The maximum namespace length of sharded collections is less than that of unsharded ones since
+    // the namespace of the cached chunks metadata, local to each shard, is composed by the
+    // namespace of the related sharded collection (i.e., config.cache.chunks.<ns>).
+    constexpr static size_t MaxNsShardedCollectionLen = 235;  // 255 - len(ChunkType::ShardNSPrefix)
+
     // Reserved system namespaces
 
     // Namespace for the admin database
diff --git a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
index 68af0777512..2a16c5bd554 100644
--- a/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
+++ b/src/mongo/db/s/config/configsvr_shard_collection_command.cpp
@@ -270,6 +270,11 @@ public:
                 str::stream() << "sharding not enabled for db " << nss.db(),
                 dbType.getSharded());
 
+        uassert(ErrorCodes::InvalidNamespace,
+                str::stream() << "Namespace too long. Namespace: " << nss
+                              << " Max: " << NamespaceString::MaxNsShardedCollectionLen,
+                nss.size() <= NamespaceString::MaxNsShardedCollectionLen);
+
         // Get variables required throughout this command.
 
         auto proposedKey(request.getKey().getOwned());
diff --git a/src/mongo/s/catalog/type_chunk.cpp b/src/mongo/s/catalog/type_chunk.cpp
index 06cebc73e6e..3180078395c 100644
--- a/src/mongo/s/catalog/type_chunk.cpp
+++ b/src/mongo/s/catalog/type_chunk.cpp
@@ -44,6 +44,10 @@
 namespace mongo {
 
 const NamespaceString ChunkType::ConfigNS("config.chunks");
+
+// The final namespace of the cached chunks metadata is composed of the namespace of the related
+// sharded collection (i.e., config.cache.chunks.<ns>). As a result, the maximum namespace length of
+// sharded collections is reduced. See NamespaceString::MaxNsShardedCollectionLen.
 const std::string ChunkType::ShardNSPrefix = "config.cache.chunks.";
 
 const BSONField<OID> ChunkType::name("_id");