SERVER-31590 Release unused cursors in the cache before awaiting oplog deletion

5 files changed, 24 insertions, 4 deletions

diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
index 8a81f75b559..eadf2910eb1 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_record_store.cpp
@@ -1034,7 +1034,9 @@ bool WiredTigerRecordStore::yieldAndAwaitOplogDeletionRequest(OperationContext*
 
     // The top-level locks were freed, so also release any potential low-level (storage engine)
     // locks that might be held.
-    opCtx->recoveryUnit()->abandonSnapshot();
+    WiredTigerRecoveryUnit* recoveryUnit = (WiredTigerRecoveryUnit*)opCtx->recoveryUnit();
+    recoveryUnit->abandonSnapshot();
+    recoveryUnit->beginIdle();
 
     // Wait for an oplog deletion request, or for this record store to have been destroyed.
     oplogStones->awaitHasExcessStonesOrDead();
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
index 8ef94e8ff97..8be67c449a5 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.cpp
@@ -294,6 +294,13 @@ void WiredTigerRecoveryUnit::setIsOplogReader() {
     _isOplogReader = true;
 }
 
+void WiredTigerRecoveryUnit::beginIdle() {
+    // Close all cursors, we don't want to keep any old cached cursors around.
+    if (_session) {
+        _session->closeAllCursors("");
+    }
+}
+
 // ---------------------
 
 WiredTigerCursor::WiredTigerCursor(const std::string& uri,
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
index 4b815539e00..397d17a142b 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h
@@ -94,6 +94,12 @@ public:
     void setIsOplogReader();
 
     /**
+     * Enter a period of wait or computation during which there are no WT calls.
+     * Any non-relevant cached handles can be closed.
+     */
+    void beginIdle();
+
+    /**
      * Returns a session without starting a new WT txn on the session. Will not close any already
      * running session.
      */
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.cpp b/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.cpp
index fdffe30c5e2..11cd1594b02 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.cpp
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.cpp
@@ -127,9 +127,10 @@ void WiredTigerSession::releaseCursor(uint64_t id, WT_CURSOR* cursor) {
 void WiredTigerSession::closeAllCursors(const std::string& uri) {
     invariant(_session);
 
+    bool all = (uri == "");
     for (auto i = _cursors.begin(); i != _cursors.end();) {
         WT_CURSOR* cursor = i->_cursor;
-        if (cursor && uri == cursor->uri) {
+        if (cursor && (all || uri == cursor->uri)) {
             invariantWTOK(cursor->close(cursor));
             i = _cursors.erase(i);
         } else
diff --git a/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.h b/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.h
index 80fa93016c7..5f8045ee2de 100644
--- a/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.h
+++ b/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.h
@@ -98,6 +98,10 @@ public:
 
     void closeCursorsForQueuedDrops(WiredTigerKVEngine* engine);
 
+    /**
+     * Closes all cached cursors matching the uri.  If the uri is empty,
+     * all cached cursors are closed.
+     */
     void closeAllCursors(const std::string& uri);
 
     int cursorsOut() const {
@@ -173,8 +177,8 @@ public:
     void closeCursorsForQueuedDrops();
 
     /**
-     * Closes all cached cursors and ensures that previously opened cursors will be closed on
-     * release.
+     * Closes all cached cursors matching the uri.  If the uri is empty,
+     * all cached cursors are closed.
      */
     void closeAllCursors(const std::string& uri);