Allow using different listing strategies

docs/components/compact.md

@@ -279,6 +279,15 @@ usage: thanos compact [<flags>]
 Continuously compacts blocks in an object store bucket.
 
 Flags:
+      --block-discovery-strategy="concurrent"
+                                One ofconcurrent, recursive. When set to
+                                concurrent, stores will concurrently issue
+                                one call per directory to discover active
+                                blocks in the bucket. The recursive strategy
+                                iterates through all objects in the bucket,
+                                recursively traversing into each directory.
+                                This avoids N+1 calls at the expense of having
+                                slower bucket iterations.
       --block-files-concurrency=1
                                 Number of goroutines to use when
                                 fetching/uploading block files from object

docs/components/store.md

@@ -29,6 +29,15 @@ Store node giving access to blocks in a bucket provider. Now supported GCS, S3,
 Azure, Swift, Tencent COS and Aliyun OSS.
 
 Flags:
+      --block-discovery-strategy="concurrent"
+                                 One ofconcurrent, recursive. When set to
+                                 concurrent, stores will concurrently issue
+                                 one call per directory to discover active
+                                 blocks in the bucket. The recursive strategy
+                                 iterates through all objects in the bucket,
+                                 recursively traversing into each directory.
+                                 This avoids N+1 calls at the expense of having
+                                 slower bucket iterations.
       --block-meta-fetch-concurrency=32
                                  Number of goroutines to use when fetching block
                                  metadata from object storage.