bulk updates for all drawings now, after parsing.

parsers/drawings.py

@@ -122,7 +122,7 @@ def _set_filesize_and_check(fullpath, model_obj, parser_label, url_prefix="/dwgd
         return False
 
     model_obj.filesize = size
-    model_obj.save()
+    # Do not save here; caller should include 'filesize' in the bulk update set.
     if size <= 0:
         message = f"! Zero length {parser_label.lower()} file {fullpath}"
         print(message)
@@ -218,7 +218,6 @@ def _process_reference(dwgfile, path, parser_label="Tunnel"):
         if hasattr(dwgfile, 'dwgcontains'):
             dwgfile.dwgcontains.add(rdwgfile)
 
-    dwgfile.save()
     return None, None
 
 
@@ -246,8 +245,9 @@ def settherionfileinfo(filetuple):
     thtype, therionfile = filetuple
 
     ff = Path(settings.DRAWINGS_DATA) / therionfile.dwgpath
-    if not _set_filesize_and_check(ff, therionfile, "Therion"):
-        return
+    modified = set()
+    if _set_filesize_and_check(ff, therionfile, "Therion"):
+        modified.add("filesize")
 
     ttext = _read_text_file(ff)
 
@@ -255,6 +255,7 @@ def settherionfileinfo(filetuple):
     # print(len(re.findall(r"line", ttext)))
     if thtype == "th":
         therionfile.npaths = len(rx_input.findall(ttext))
+        modified.add("npaths")
         if wallet_texts := rx_ref.findall(ttext):
             # print(f"#ref {therionfile.dwgname} : {wallet_text}")
             if wallets := Wallet.objects.filter(walletname__in=wallet_texts): # ! Django idiom not used elsewhere. A filter using a list of strings.
@@ -262,6 +263,7 @@ def settherionfileinfo(filetuple):
                     therionfile.dwgwallets.add(w)                
     elif thtype == "th2":
         therionfile.npaths = len(rx_line.findall(ttext))
+        modified.add("npaths")
 
         # scan and look for survex blocks that might have been included, and image scans (as for tunnel drawings)
         # which would populate dwgfile.survexfile
@@ -293,7 +295,8 @@ def settherionfileinfo(filetuple):
         DataIssue.objects.create(parser="xTherion", message=message, url=f"/dwgdataraw/{therionfile.dwgpath}")
         findimportinsert(therionfile, inp)
 
-    therionfile.save()
+    # Defer saving scalar fields; caller will perform bulk_update.
+    return modified
 
 
 def settnlfileinfo(dwgfile):
@@ -307,13 +310,14 @@ def settnlfileinfo(dwgfile):
     *ref wallet identifiers may be found in at least two different places in tunnel files.
     """
     ff = Path(settings.DRAWINGS_DATA) / dwgfile.dwgpath
-    if not _set_filesize_and_check(ff, dwgfile, "Tunnel"):
-        return
+    modified = set()
+    if _set_filesize_and_check(ff, dwgfile, "Tunnel"):
+        modified.add("filesize")
 
     ttext = _read_text_file(ff)
 
     dwgfile.npaths = len(rx_skpath.findall(ttext))
-    # dwgfile.save()
+    modified.add("npaths")
 
     # example drawing file in Tunnel format.
     # <tunnelxml tunnelversion="version2009-06-21 Matienzo" tunnelproject="ireby" tunneluser="goatchurch" tunneldate="2009-06-29 23:22:17">
@@ -335,11 +339,11 @@ def settnlfileinfo(dwgfile):
             message =  f"  ! wallet not found referenced from {dwgfile} -- '{refs}' ({e}) "
             print(message)
             DataIssue.objects.create(parser="Tunnel", message=message, url=f"/dwgdataraw/{dwgfile}")
-
     # should also scan and look for survex blocks that might have been included, and image scans
     # which would populate dwgfile.survexfile
 
-    dwgfile.save()
+    # Defer scalar saves to bulk_update; return set of modified fields
+    return modified
 
 
 def setdrwfileinfo(dwgfile):
@@ -348,13 +352,13 @@ def setdrwfileinfo(dwgfile):
 
     """
     ff = Path(settings.DRAWINGS_DATA) / dwgfile.dwgpath
+    # Set filesize (if available) but do not save; return modified field names
     if not _set_filesize_and_check(ff, dwgfile, "drawings"):
-        return
-    # nothing more to parse for generic files
+        return set()
+    return {"filesize"}
 
 def load_drawings_files():
-    """Breadth first search of drawings directory looking for sub-directories and *.xml filesize
-    
+    """    
     Why do we have all this detection of file types/! Why not use get_mime_types ?
     What is it all for ??
 
@@ -418,18 +422,39 @@ def load_drawings_files():
     ext_priority = {'th2': 0, 'th': 1}
     all_xml.sort(key=lambda t: ext_priority.get(t[0], 2))
 
+    print(f" - Drawing found, starting parsing...")
+
+    # Process files and collect modified scalar fields for bulk update
+    modified_map = {}  # {DrawingFile instance: set(fields)}
     for extension, filename, pathobj in all_xml:
+        modified = set()
         if extension in {"pdf", "txt", "svg", "jpg", "png", ""}:
-            setdrwfileinfo(filename)
+            modified = setdrwfileinfo(filename) or set()
         elif extension == "xml":
-            settnlfileinfo(filename)
+            modified = settnlfileinfo(filename) or set()
         # important to import .th2 files before .th so that we can assign them when found in .th files
         elif extension == "th2":
-            settherionfileinfo(("th2", filename))
+            modified = settherionfileinfo(("th2", filename)) or set()
         elif extension == "th":
-            settherionfileinfo(("th", filename))
+            modified = settherionfileinfo(("th", filename)) or set()
 
-    print(f" - Drawings parsed")
+        if modified:
+            modified_map.setdefault(filename, set()).update(modified)
+
+    # Bulk update scalar fields grouped by identical field-sets to use bulk_update efficiently
+    from collections import defaultdict
+
+    groups = defaultdict(list)  # {tuple(fields): [instances]}
+    for inst, fields in modified_map.items():
+        key = tuple(sorted(fields))
+        groups[key].append(inst)
+
+    for fields_tuple, instances in groups.items():
+        fields_list = list(fields_tuple)
+        # Use a conservative batch size
+        DrawingFile.objects.bulk_update(instances, fields_list, batch_size=500)
+
+    print(f" - Drawings parsed and database updated.")
 
     # for drawfile in DrawingFile.objects.all():
     # SetTunnelfileInfo(drawfile)