[t:4553] Merging temporary cursor malloc changes into main.

git-svn-id: file:///svn/toku/tokudb@40177 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/brt-internal.h

@@ -577,6 +577,7 @@ struct brt_cursor {
     BOOL is_snapshot_read; // true if query is read_committed, false otherwise
     BOOL is_leaf_mode;
     BOOL disable_prefetching;
+    BOOL is_temporary;
     TOKUTXN ttxn;
     struct brt_cursor_leaf_info  leaf_info;
 };

newbrt/brt.c

@@ -4387,6 +4387,7 @@ int toku_brt_cursor (
     cursor->is_leaf_mode = FALSE;
     cursor->ttxn = ttxn;
     cursor->disable_prefetching = disable_prefetching;
+    cursor->is_temporary = FALSE;
     if (1) {
     toku_spin_lock(&brt->cursors_lock);
     toku_list_push(&brt->cursors, &cursor->cursors_link);
@@ -4396,6 +4397,11 @@ int toku_brt_cursor (
     return 0;
 }
 
+void
+toku_brt_cursor_set_temporary(BRT_CURSOR brtcursor) {
+    brtcursor->is_temporary = TRUE;
+}
+
 void
 toku_brt_cursor_set_leaf_mode(BRT_CURSOR brtcursor) {
     brtcursor->is_leaf_mode = TRUE;
@@ -5090,10 +5096,12 @@ got_a_good_value:
             }
 
             brt_cursor_cleanup_dbts(brtcursor);
+            if (!brtcursor->is_temporary) {
                 brtcursor->key.data = toku_memdup(key, keylen);
                 brtcursor->val.data = toku_memdup(val, vallen);
                 brtcursor->key.size = keylen;
                 brtcursor->val.size = vallen;
+            }
             //The search was successful.  Prefetching can continue.
             *doprefetch = TRUE;
         }

newbrt/brt.h

@@ -191,6 +191,9 @@ int toku_verify_brt_with_progress (BRT brt, int (*progress_callback)(void *extra
 typedef struct brt_cursor *BRT_CURSOR;
 int toku_brt_cursor (BRT, BRT_CURSOR*, TOKUTXN, BOOL, BOOL)  __attribute__ ((warn_unused_result));
 void toku_brt_cursor_set_leaf_mode(BRT_CURSOR);
+// Sets a boolean on the brt cursor that prevents uncessary copying of
+// the cursor duing a one query.
+void toku_brt_cursor_set_temporary(BRT_CURSOR);
 int toku_brt_cursor_is_leaf_mode(BRT_CURSOR);
 void toku_brt_cursor_set_range_lock(BRT_CURSOR, const DBT *, const DBT *, BOOL, BOOL);
 

src/ydb_cursor.c

@@ -878,6 +878,13 @@ toku_db_cursor_internal(DB * db, DB_TXN * txn, DBC ** c, u_int32_t flags, int is
         );
     assert(r == 0 || r == TOKUDB_MVCC_DICTIONARY_TOO_NEW);
     if (r == 0) {
+        // Set the is_temporary_cursor boolean inside the brt node so
+        // that a query only needing one cursor will not perform
+        // unecessary malloc calls.
+        if (is_temporary_cursor) {
+            toku_brt_cursor_set_temporary(dbc_struct_i(result)->c);
+        }
+
         *c = result;
     }
     else {