Merge pull request #13892 from wietzesuijker/perf/multidim-skip-gmac-remote

Multidim: skip .gmac cache stat for non-local filesystems

Author: rouault

autotest/gdrivers/zarr_driver.py

@@ -6249,7 +6249,6 @@ def test_zarr_read_simple_sharding_network():
             handler.add("HEAD", "/test.zarr/zarr.AUX", 404)
             handler.add("HEAD", "/test.zarr/zarr.json.aux", 404)
             handler.add("HEAD", "/test.zarr/zarr.json.AUX", 404)
-            handler.add("HEAD", "/test.zarr/zarr.json.gmac", 404)
             handler.add("HEAD", "/test.zarr/c/0/0", 200, {"Content-Length": "65536"})
             handler.add(
                 "GET",

gcore/gdalmultidim.cpp

@@ -4362,6 +4362,13 @@ GDALMDArray::GetCacheRootGroup(bool bCanCreate,
     if (pszProxy != nullptr)
         osCacheFilenameOut = pszProxy;
 
+    // .gmac sidecars are local-only; skip stat for non-local filesystems.
+    if (!bCanCreate && pszProxy == nullptr &&
+        !VSIIsLocal(osCacheFilenameOut.c_str()))
+    {
+        return nullptr;
+    }
+
     std::unique_ptr<GDALDataset> poDS;
     VSIStatBufL sStat;
     if (VSIStatL(osCacheFilenameOut.c_str(), &sStat) == 0)