SERVER-19083 Strip out WT internal metadata from creation string.

Ensures that the creation strings returned by the "collStats" command
can be used to construct an identically configured collection or index.

2 files changed, 49 insertions, 1 deletions

diff --git a/jstests/noPassthroughWithMongod/wt_roundtrip_creation_string.js b/jstests/noPassthroughWithMongod/wt_roundtrip_creation_string.js
new file mode 100644
index 00000000000..d927cbb541a
--- /dev/null
+++ b/jstests/noPassthroughWithMongod/wt_roundtrip_creation_string.js
@@ -0,0 +1,48 @@
+/**
+ * Tests that the creation string returned by the collStats command can be used to create a
+ * collection or index with the same WiredTiger options.
+ */
+(function() {
+    'use strict';
+
+    // Skip this test if not running with the "wiredTiger" storage engine.
+    if (db.serverStatus().storageEngine.name !== 'wiredTiger') {
+        jsTest.log('Skipping test because storageEngine is not "wiredTiger"');
+        return;
+    }
+
+    var collNamePrefix = 'wt_roundtrip_creation_string';
+
+    // Drop the collections used by the test to ensure that the create commands don't fail because
+    // the collections already exist.
+    db[collNamePrefix].source.drop();
+    db[collNamePrefix].dest.drop();
+
+    assert.commandWorked(db.createCollection(collNamePrefix + '.source'));
+    assert.commandWorked(db[collNamePrefix].source.createIndex({a: 1}, {name: 'a_1'}));
+
+    var collStats = db.runCommand({collStats: collNamePrefix + '.source'});
+    assert.commandWorked(collStats);
+
+    assert.commandWorked(db.runCommand({
+        create: collNamePrefix + '.dest',
+        storageEngine: {
+            wiredTiger: {
+                configString: collStats.wiredTiger.creationString
+            }
+        }
+    }), 'unable to create collection using the creation string of another collection');
+
+    assert.commandWorked(db.runCommand({
+        createIndexes: collNamePrefix + '.dest',
+        indexes: [{
+            key: {b: 1},
+            name: 'b_1',
+            storageEngine: {
+                wiredTiger: {
+                    configString: collStats.indexDetails.a_1.creationString
+                }
+            }
+        }]
+    }), 'unable to create index using the creation string of another index');
+})();
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
index c71672d5522..203c5722c73 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_util.cpp
@@ -99,7 +99,7 @@ void WiredTigerUtil::fetchTypeAndSourceURI(OperationContext* opCtx,
 
 StatusWith<std::string> WiredTigerUtil::getMetadata(OperationContext* opCtx, StringData uri) {
     invariant(opCtx);
-    WiredTigerCursor curwrap("metadata:", WiredTigerSession::kMetadataTableId, false, opCtx);
+    WiredTigerCursor curwrap("metadata:create", WiredTigerSession::kMetadataTableId, false, opCtx);
     WT_CURSOR* cursor = curwrap.get();
     invariant(cursor);
     std::string strUri = uri.toString();