Speedup deletion from spill_pgs

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 15d2e6bdb7a8984a4763a42eed78ce0f997c11de..842008578c349c484df90b2618588d0d6517d1ed 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1475,6 +1475,17 @@ mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
                txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
                if (!txn->mt_spill_pgs)
                        return ENOMEM;
+       } else {
+               /* strip any dups */
+               MDB_IDL sl = txn->mt_spill_pgs;
+               unsigned int num = sl[0];
+               j=1;
+               for (i=1; i<=num; i++) {
+                       if (sl[i] == sl[j])
+                               continue;
+                       sl[++j] = sl[i];
+               }
+               sl[0] = j;
        }
 
        /* Preserve pages which may soon be dirtied again */
@@ -1813,10 +1824,15 @@ mdb_page_unspill(MDB_txn *tx0, MDB_page *mp, MDB_page **ret)
                                        mdb_page_copy(np, mp, env->me_psize);
                        }
                        if (txn == tx0) {
-                               /* If in current txn, this page is no longer spilled */
-                               for (; x < txn->mt_spill_pgs[0]; x++)
+                               /* If in current txn, this page is no longer spilled.
+                                * If it happens to be the last page, truncate the spill list.
+                                * Otherwise temporarily dup its neighbor over it. Dups will
+                                * be stripped out later by the next mdb_page_spill run.
+                                */
+                               if (x == txn->mt_spill_pgs[0])
+                                       txn->mt_spill_pgs[0]--;
+                               else
                                        txn->mt_spill_pgs[x] = txn->mt_spill_pgs[x+1];
-                               txn->mt_spill_pgs[0]--;
                        }       /* otherwise, if belonging to a parent txn, the
                                 * page remains spilled until child commits
                                 */