1 files changed, 92 insertions, 0 deletions
diff --git a/jstests/sharding/remove_shard_near_doc_size_limit.js b/jstests/sharding/remove_shard_near_doc_size_limit.js
new file mode 100644
index 00000000000..c918f7000db
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+++ b/jstests/sharding/remove_shard_near_doc_size_limit.js
@@ -0,0 +1,92 @@
+/*
+ * This test reproduces the error reported in HELP-22995. It creates a jumbo chunk with documents
+ * that are close to the 16MB document size limit to force the batching code in move chunk to
+ * consider adding them together in a batch. It ensures that the proper document size is considered
+ * and that we can still migrate when calling removeShard.
+ *
+ * @tags: [requires_fcv_44, multiversion_incompatible]
+ */
+
+(function() {
+'use strict';
+const dbName = "test";
+const collName = "user";
+const ns = dbName + "." + collName;
+const shardKeys = [-1, 1];
+
+// This number is chosen so that the chunks are considered 'large' as defined by
+// the MigrationChunkClonerSourceLegacy class. Currently, that class considers chunks containing
+// more than the following number of documents as 'large':
+//    (13/10) * MaxChunkSize / avgRecSize (MaxChunkSize is 64MB by default)
+const numDocs = 10;
+
+// Size is slightly under the 16MB document size limit. This ensures that any two documents must be
+// be in separate batches when cloning.
+const bigDocSize = 16 * 1024 * 1024 - 4096;
+const bigDocPayload = "x".repeat(bigDocSize);
+
+let st = new ShardingTest({shards: 2});
+assert.commandWorked(st.s.adminCommand({enableSharding: dbName}));
+st.ensurePrimaryShard(dbName, st.shard0.shardName);
+
+jsTest.log("Sharding collection with one chunk on each shard.");
+assert.commandWorked(st.s.adminCommand({shardCollection: ns, key: {x: 1}}));
+assert.commandWorked(st.s.adminCommand({split: ns, middle: {x: 0}}));
+assert.commandWorked(st.s.adminCommand({moveChunk: ns, find: {x: 1}, to: st.shard1.shardName}));
+
+function removeShardAndWait(shardName) {
+    const removeShardCmd = {removeShard: shardName};
+    const res = st.s.adminCommand(removeShardCmd);
+
+    assert.commandWorked(res);
+    assert(res.state === "started");
+
+    assert.soon(function() {
+        let res = st.s.adminCommand(removeShardCmd);
+        if (res.state === "completed") {
+            return true;
+        } else {
+            jsTest.log("Still waiting for shard removal to complete:");
+            printjson(res);
+            assert.commandWorked(st.s.adminCommand({clearJumboFlag: ns, find: {"x": 1}}));
+            return false;
+        }
+    });
+
+    jsTest.log("Shard removal complete.");
+}
+
+function assertDocsExist(shardKeys, numDocs, payloadSize) {
+    shardKeys.forEach(key => {
+        for (let i = 0; i < numDocs; i++) {
+            let db = st.rs0.getPrimary().getDB(dbName);
+            let query = {x: key, seq: i};
+            let doc = db.getCollection(collName).findOne(query);
+            assert(doc);
+            let payload = doc.data;
+            assert.eq(payload.length,
+                      payloadSize,
+                      tojson(query) + " does not have the expected payload length of " +
+                          payloadSize + " bytes");
+        }
+    });
+}
+
+jsTest.log("Insert " + numDocs + " documents with " + bigDocSize + " bytes each.");
+shardKeys.forEach(key => {
+    for (let i = 0; i < numDocs; i++) {
+        let doc = {x: key, seq: i, data: bigDocPayload};
+        assert.commandWorked(st.s.getCollection(ns).insert(doc));
+    }
+});
+
+// Start balancer to migrate chunks from the removed shard.
+assert.commandWorked(st.s.getDB("config").settings.update(
+    {_id: "balancer"}, {$set: {attemptToBalanceJumboChunks: true}}, true));
+st.startBalancer();
+
+removeShardAndWait(st.shard1.shardName);
+assertDocsExist(shardKeys, numDocs, bigDocSize);
+
+st.stop();
+})();