Set PerThreadCache as readonly after deleting a change

Apply the same optimisation made for Change-Id: I1b71bfcf to
the production of events after deleting a change.

The same considerations of performance improvement and reduction
of /meta refs lookup are valid in this use-case.

Release-Notes: enable the read-only cache of /meta refs for deleted changes
Change-Id: Ic04e9257b7801bd331390679e00e1f980a9d1d19

2 files changed, 16 insertions, 6 deletions

diff --git a/java/com/google/gerrit/server/events/StreamEventsApiListener.java b/java/com/google/gerrit/server/events/StreamEventsApiListener.java
index d7801d0483..6a530ed764 100644
--- a/java/com/google/gerrit/server/events/StreamEventsApiListener.java
+++ b/java/com/google/gerrit/server/events/StreamEventsApiListener.java
@@ -541,12 +541,17 @@ public class StreamEventsApiListener
   @Override
   public void onChangeDeleted(ChangeDeletedListener.Event ev) {
     try {
-      ChangeNotes notes = getNotes(ev.getChange());
-      Change change = notes.getChange();
-      ChangeDeletedEvent event = new ChangeDeletedEvent(change);
+      Change change;
+      ChangeDeletedEvent event;
 
-      event.change = changeAttributeSupplier(change, notes);
-      event.deleter = accountAttributeSupplier(ev.getWho());
+      try (ReadonlyRequestWindow window = PerThreadCache.openReadonlyRequestWindow()) {
+        ChangeNotes notes = getNotes(ev.getChange());
+        change = notes.getChange();
+        event = new ChangeDeletedEvent(change);
+
+        event.change = changeAttributeSupplier(change, notes);
+        event.deleter = accountAttributeSupplier(ev.getWho());
+      }
 
       dispatcher.run(d -> d.postEvent(change, event));
     } catch (OrmException e) {
diff --git a/java/com/google/gerrit/server/extensions/events/ChangeDeleted.java b/java/com/google/gerrit/server/extensions/events/ChangeDeleted.java
index d9eb9f98b6..0c724b81c2 100644
--- a/java/com/google/gerrit/server/extensions/events/ChangeDeleted.java
+++ b/java/com/google/gerrit/server/extensions/events/ChangeDeleted.java
@@ -21,6 +21,8 @@ import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.events.ChangeDeletedListener;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.cache.PerThreadCache;
+import com.google.gerrit.server.cache.PerThreadCache.ReadonlyRequestWindow;
 import com.google.gerrit.server.plugincontext.PluginSetContext;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -45,7 +47,10 @@ public class ChangeDeleted {
       return;
     }
     try {
-      Event event = new Event(util.changeInfo(change), util.accountInfo(deleter), when);
+      Event event;
+      try (ReadonlyRequestWindow window = PerThreadCache.openReadonlyRequestWindow()) {
+        event = new Event(util.changeInfo(change), util.accountInfo(deleter), when);
+      }
       listeners.runEach(l -> l.onChangeDeleted(event));
     } catch (OrmException e) {
       logger.atSevere().withCause(e).log("Couldn't fire event");