SERVER-63332 Log random parameters for defragment_large_collection jstest

2 files changed, 18 insertions, 7 deletions

diff --git a/jstests/sharding/defragment_large_collection.js b/jstests/sharding/defragment_large_collection.js
index 46b649a394b..1422c314fc3 100644
--- a/jstests/sharding/defragment_large_collection.js
+++ b/jstests/sharding/defragment_large_collection.js
@@ -21,6 +21,9 @@ const maxChunkFillMB = 20;
 const maxChunkSizeMB = 30;
 const chunkSpacing = 1000;
 
+jsTest.log("Creating new test with " + numCollections + " collections over " + numShards +
+           " shards.");
+
 const st = new ShardingTest({
     mongos: 1,
     shards: numShards,
@@ -47,10 +50,6 @@ for (let i = 0; i < numCollections; ++i) {
     defragmentationUtil.createFragmentedCollection(
         st.s, coll.getFullName(), numChunks, maxChunkFillMB, numZones, docSizeBytes, chunkSpacing);
 
-    const beginningNumberChunks =
-        findChunksUtil.countChunksForNs(st.s.getDB('config'), coll.getFullName());
-    jsTest.log("Create collection " + coll + " with " + beginningNumberChunks + " chunks.");
-
     collections.push(coll);
 }
 
diff --git a/jstests/sharding/libs/defragmentation_util.js b/jstests/sharding/libs/defragmentation_util.js
index 37b6a2c786d..65a3e49eb18 100644
--- a/jstests/sharding/libs/defragmentation_util.js
+++ b/jstests/sharding/libs/defragmentation_util.js
@@ -1,20 +1,32 @@
 var defragmentationUtil = (function() {
     load("jstests/sharding/libs/find_chunks_util.js");
 
-    // This function creates a randomized, fragmented collection. It does not necessarily make a
-    // collection with exactly numChunks chunks nor exactly numZones zones.
     let createFragmentedCollection = function(
         mongos, ns, numChunks, maxChunkFillMB, numZones, docSizeBytes, chunkSpacing) {
+        jsTest.log("Creating fragmented collection " + ns + " with parameters: numChunks = " +
+                   numChunks + ", numZones = " + numZones + ", docSizeBytes = " + docSizeBytes +
+                   ", maxChunkFillMB = " + maxChunkFillMB + ", chunkSpacing = " + chunkSpacing);
         assert.commandWorked(mongos.adminCommand({shardCollection: ns, key: {key: 1}}));
 
         createAndDistributeChunks(mongos, ns, numChunks, chunkSpacing);
         createRandomZones(mongos, ns, numZones, chunkSpacing);
         fillChunksToRandomSize(mongos, ns, docSizeBytes, maxChunkFillMB);
+
+        const beginningNumberChunks = findChunksUtil.countChunksForNs(mongos.getDB('config'), ns);
+        const beginningNumberZones = mongos.getDB('config').tags.countDocuments({ns: ns});
+        jsTest.log("Collection " + ns + " created with " + beginningNumberChunks + " chunks and " +
+                   beginningNumberZones + " zones.");
     };
 
     let createAndDistributeChunks = function(mongos, ns, numChunks, chunkSpacing) {
         const shards = mongos.getCollection('config.shards').find().toArray();
-        for (let i = -Math.floor(numChunks / 2); i <= Math.floor(numChunks / 2); i++) {
+        const existingNumChunks = findChunksUtil.countChunksForNs(mongos.getDB('config'), ns);
+        let numChunksToCreate = numChunks - existingNumChunks;
+        if (numChunksToCreate <= 0) {
+            return;
+        }
+        for (let i = -Math.floor(numChunksToCreate / 2); i < Math.ceil(numChunksToCreate / 2);
+             i++) {
             assert.commandWorked(mongos.adminCommand({split: ns, middle: {key: i * chunkSpacing}}));
             assert.soon(() => {
                 let toShard = Random.randInt(shards.length);