SERVER-22178 Always retry sorted findAndModify upon write conflict.

Previously, if there was a WriteConflictException while actually doing
the update or delete, we would retry the findAndModify, but if the
update or delete stage detected that the document was already deleted
or that it no longer matched the predicate, it would not retry. This
patch ensures the findAndModify will be retried in either of those
scenarios.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/mongo/db/exec/delete.h b/src/mongo/db/exec/delete.h
index 55879182adb..9a71c597e63 100644
--- a/src/mongo/db/exec/delete.h
+++ b/src/mongo/db/exec/delete.h
@@ -44,7 +44,7 @@ struct DeleteStageParams {
           fromMigrate(false),
           isExplain(false),
           returnDeleted(false),
-          canonicalQuery(NULL) {}
+          canonicalQuery(nullptr) {}
 
     // Should we delete all documents returned from the child (a "multi delete"), or at most one
     // (a "single delete")?
@@ -62,6 +62,9 @@ struct DeleteStageParams {
 
     // The parsed query predicate for this delete. Not owned here.
     CanonicalQuery* canonicalQuery;
+
+    // The user-requested sort specification. Currently used just for findAndModify.
+    BSONObj sort;
 };
 
 /**
@@ -105,6 +108,12 @@ public:
     static long long getNumDeleted(const PlanExecutor& exec);
 
 private:
+    /**
+     * Stores 'idToRetry' in '_idRetrying' so the delete can be retried during the next call to
+     * work(). Always returns NEED_YIELD and sets 'out' to WorkingSet::INVALID_ID.
+     */
+    StageState prepareToRetryWSM(WorkingSetID idToRetry, WorkingSetID* out);
+
     DeleteStageParams _params;
 
     // Not owned by us.