update only changed fields optimisation now done

core/models/wallets.py

@@ -329,7 +329,7 @@ class Wallet(models.Model):
             return None
         else:
             self.walletyear = datetime.date(year, 1, 1)
-            self.save()
+            self.save(update_fields=["walletdate"])
             return str(year)
 
     # Yes this is horribly, horribly inefficient, esp. for a page that have date, people and cave in it

parsers/survex.py

@@ -106,7 +106,7 @@ def set_walletdate(w):
     if not w.date():  # sets .walletdate as a side-effect if it gets it from JSON
         d = datewallet(w, earliest)  # Not in JSON, so checks all the survex blocks
         w.walletdate = d
-        w.save()
+        w.save(update_fields=["walletdate"])
 
 def stash_data_issue(parser=None, message=None, url=None, sb=None):
     """Avoid hitting the database for error messages until the end of the import
@@ -1212,7 +1212,7 @@ class LoadingSurvex:
         Currently this just sets a flag that the survex block is not CUCC
         """
         survexblock.foreigners = True
-        survexblock.save()
+        survexblock.save(update_fields=["foreigners"])
 
     def LoadSurvexRef(self, survexblock, args):
         """Interpret the *ref record, and all the many variants
@@ -1303,8 +1303,9 @@ class LoadingSurvex:
                     
             else:
                 survexblock.scanswallet = manywallets[0]  # this is a ForeignKey field
-                survexblock.save()
-                # This is where we chould check that the wallet JSON contains a link to the survexfile
+                # Only save if changed
+                survexblock.save(update_fields=["scanswallet"])
+                # This is where we should check that the wallet JSON contains a link to the survexfile
                 # and that the JSON date and walletdate are set correctly to the survexblock date.
                 set_walletdate(survexblock.scanswallet)
         else:
@@ -1555,7 +1556,7 @@ class LoadingSurvex:
             # print(f"\n - New directory '{newdirectory}' for cave '{cave}'",file=sys.stderr)
             if not cave.survex_file:
                 cave.survex_file = svxid + ".svx"
-                cave.save()
+                cave.save(update_fields=["survex_file"])
                 # message = f" - '{cave}' had no survex_file set - setting '{svxid}.svx' writing to {cave.filename})"
                 message = f" - '{cave}' has no survex_file set - need to set to '{svxid}.svx' in {cave.filename})"
                 print("\n",message,file=sys.stderr)
@@ -2739,7 +2740,7 @@ def parse_one_file(fpath): # --------------------------------------in progress--
                 cave_svxpath = cave.survex_file[:-4] # remove .svx
             else:
                 cave.survex_file = svxpath + ".svx"
-                cave.save()
+                cave.save(update_fields=["survex_file"])
                 cave_svxpath = svxpath
             try:
                 fileroot = SurvexFile.objects.get(path=cave_svxpath)