First attempts at better use of Django query optimisation

1 files changed, 7 insertions, 6 deletions

diff --git a/core/views/logbooks.py b/core/views/logbooks.py
index 003b67f..8b62368 100644
--- a/core/views/logbooks.py
+++ b/core/views/logbooks.py
@@ -16,7 +16,7 @@ from troggle.parsers.imports import import_logbook
 """These views are for logbook items when they appear in an 'expedition' page
 and for persons: their individual pages and their perseonexpedition pages.
 
-It uses the global object TROG to hold some cached pages.
+It uses the global object TROG to hold some cached pages. USELESS as cache only works single-threaded, single-user.
 """
 
 todo = """- Fix the get_person_chronology() display bug.
@@ -91,17 +91,16 @@ def expedition(request, expeditionname):
             # print('! - expo {expeditionanme} using cached page')
             return render(request, "expedition.html", {**ts[expeditionname], "logged_in": logged_in})
 
-    expeditions = Expedition.objects.all()  # top menu only, evaluated only when template renders
 
-    entries = expo.logbookentry_set.all()
-    blocks = expo.survexblock_set.all()
+    entries = expo.logbookentry_set.only('date','title').filter(expedition=expo)
+    blocks = expo.survexblock_set.only('date','name').filter(expedition=expo).prefetch_related('scanswallet', 'survexfile')
     dateditems = list(entries) + list(blocks)  # evaluates the Django query and hits db
     dates = sorted(set([item.date for item in dateditems]))
 
-    allpersonlogentries = PersonLogEntry.objects.filter(personexpedition__expedition=expo)
+    allpersonlogentries = PersonLogEntry.objects.prefetch_related('logbook_entry').select_related('personexpedition__expedition').filter(personexpedition__expedition=expo)
 
     personexpodays = []
-    for personexpedition in expo.personexpedition_set.all():
+    for personexpedition in expo.personexpedition_set.all().prefetch_related('person'):
         expotrips = allpersonlogentries.filter(personexpedition=personexpedition)  # lazy
         expoblocks = blocks.filter(survexpersonrole__personexpedition=personexpedition)
 
@@ -118,6 +117,8 @@ def expedition(request, expeditionname):
             prow.append(pcell)
         personexpodays.append({"personexpedition": personexpedition, "personrow": prow, "sortname": personexpedition.person.last_name})
 
+    expeditions = Expedition.objects.only('year')  # top menu only, evaluated only when template renders, only need "year"
+
     ts[expeditionname] = {
         "year": int(expeditionname),
         "expedition": expo,