Use UnorderedOrdering for PatientFolder to avoid ZODB conflicts

docs/changelog.rst

@@ -4,6 +4,7 @@ Changelog
 1.6.0 (unreleased)
 ------------------
 
+- #135 Use UnorderedOrdering for PatientFolder to avoid ZODB conflicts
 - #133 Remove email invariant and add adapter to toggle email_report
 - #134 Compatibility with core#2835 (display Patients in navbar)
 - #131 Fix BehaviorRegistrationNotFound on Patient creation via JSON API

src/senaite/patient/content/configure.zcml

@@ -16,4 +16,29 @@
       factory=".analysisrequest.AnalysisRequestSchemaModifier"
       provides="archetypes.schemaextender.interfaces.ISchemaModifier"/>
 
+  <!--
+    Use plone.folder's UnorderedOrdering as the IOrdering adapter for the
+    PatientFolder.
+
+    The default DefaultOrdering keeps a `plone.folder.ordered.order`
+    PersistentList annotation that grows with the number of children:
+    every `_setObject` calls `notifyAdded` which appends to the list.
+    PersistentList has no `_p_resolveConflict()`, so two concurrent
+    appends collide and the conflict propagates to the client through
+    the publisher's retry loop. On clinical-lab installations the
+    PatientFolder accumulates one Patient per registered sample, so
+    every concurrent sample-registration that creates a new Patient
+    contends on the same annotation. With tens of thousands of children
+    the cost grows roughly with the number of entries.
+
+    Patient listings never depend on the parent folder's manual
+    ordering — they sort catalog brains. Switching IPatientFolder to
+    UnorderedOrdering removes the hot-spot at no functional cost.
+    -->
+  <adapter
+      for=".patientfolder.IPatientFolder"
+      factory="plone.folder.unordered.UnorderedOrdering"
+      provides="plone.folder.interfaces.IOrdering"
+      />
+
 </configure>

src/senaite/patient/profiles/default/metadata.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <metadata>
-  <version>1602</version>
+  <version>1603</version>
   <dependencies>
     <dependency>profile-senaite.lims:default</dependency>
   </dependencies>

src/senaite/patient/upgrade/v01_06_000.py

@@ -24,6 +24,7 @@
 from senaite.patient import logger
 from senaite.patient.config import PRODUCT_NAME
 from senaite.patient.setuphandlers import display_in_nav
+from zope.annotation.interfaces import IAnnotations
 
 version = "1.6.0"
 profile = "profile-{0}:default".format(PRODUCT_NAME)
@@ -76,3 +77,44 @@ def display_patients_navbar(tool):
     patients = api.get_portal().patients
     display_in_nav(patients)
     logger.info("Display Patients in navigation bar [DONE]")
+
+
+def drop_patientfolder_ordering_annotations(tool):
+    """Remove the legacy IOrdering annotations from the PatientFolder.
+
+    The PatientFolder now uses `plone.folder.unordered.UnorderedOrdering`
+    as its `IOrdering` adapter, so the previous default-ordering
+    annotations are no longer maintained:
+
+      - `plone.folder.ordered.order` — a `PersistentList` of every
+        child id, mutated on every `_setObject` via
+        `DefaultOrdering.notifyAdded`. With one Patient per registered
+        sample on a clinical-lab installation, this list grows to many
+        tens of thousands of entries; because `PersistentList` has no
+        `_p_resolveConflict()`, every concurrent registration that
+        creates a new Patient collided on it and the conflict
+        propagated all the way to the publisher's retry loop.
+
+      - `plone.folder.ordered.pos` — companion `OIBTree` mapping
+        child id -> position. No longer read by anything once the
+        adapter is unordered.
+
+    Removing both annotations after the adapter switch frees the
+    storage they occupy and removes a stale hot-mutation bucket from
+    the ZODB cache. The adapter override is what stops new writes
+    from touching them; this step is hygiene.
+    """
+    logger.info("Dropping IOrdering annotations from PatientFolder ...")
+    patients = api.get_portal().patients
+    ann = IAnnotations(patients)
+    had_order = "plone.folder.ordered.order" in ann
+    had_pos = "plone.folder.ordered.pos" in ann
+    if not (had_order or had_pos):
+        logger.info(
+            "Dropping IOrdering annotations from PatientFolder [SKIP] "
+            "(no annotations found)")
+        return
+    ann.pop("plone.folder.ordered.order", None)
+    ann.pop("plone.folder.ordered.pos", None)
+    patients._p_changed = True
+    logger.info("Dropping IOrdering annotations from PatientFolder [DONE]")

src/senaite/patient/upgrade/v01_06_000.zcml

@@ -2,6 +2,19 @@
     xmlns="http://namespaces.zope.org/zope"
     xmlns:genericsetup="http://namespaces.zope.org/genericsetup">
 
+  <genericsetup:upgradeStep
+      title="Drop ordering annotations from PatientFolder"
+      description="
+        Remove the plone.folder.ordered.order PersistentList and
+        plone.folder.ordered.pos OIBTree annotations from the PatientFolder.
+        The folder now uses UnorderedOrdering as its IOrdering adapter, so
+        these annotations are no longer maintained and become a stale ZODB
+        conflict spot if left in place."
+      source="1602"
+      destination="1603"
+      handler=".v01_06_000.drop_patientfolder_ordering_annotations"
+      profile="senaite.patient:default"/>
+
   <genericsetup:upgradeStep
       title="Display Patients in the navbar"
       description="