Reduce excessive memcpy in mdb_split

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index d1efdd1b24d4cad1ba86d49eb8def9c13b033cdf..7487f7f9e38fb7afcfc498fd3e27c755f34d774a 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -3216,7 +3216,7 @@ mdb_split(MDB_txn *txn, MDB_dbi dbi, MDB_page **mpp, unsigned int *newindxp,
        unsigned int     i, j, split_indx, nkeys, pmax;
        MDB_node        *node;
        MDB_val  sepkey, rkey, rdata;
-       MDB_page        *copy;
+       MDB_page        *copy, *cptr;
        MDB_dpage       *mdp, *rdp, *pdp;
        MDB_dhead *dh;
        DKBUF;
@@ -3301,13 +3301,6 @@ mdb_split(MDB_txn *txn, MDB_dbi dbi, MDB_page **mpp, unsigned int *newindxp,
                goto newsep;
        }
 
-       /* Move half of the keys to the right sibling. */
-       if ((copy = malloc(txn->mt_env->me_psize)) == NULL)
-               return ENOMEM;
-       memcpy(copy, &mdp->p, txn->mt_env->me_psize);
-       memset(&mdp->p.mp_ptrs, 0, txn->mt_env->me_psize - PAGEHDRSZ);
-       mdp->p.mp_lower = PAGEHDRSZ;
-       mdp->p.mp_upper = txn->mt_env->me_psize;
        /* For leaf pages, check the split point based on what
         * fits where, since otherwise add_node can fail.
         */
@@ -3356,7 +3349,7 @@ split2:
                sepkey.mv_size = newkey->mv_size;
                sepkey.mv_data = newkey->mv_data;
        } else {
-               node = NODEPTR(copy, split_indx);
+               node = NODEPTR(&mdp->p, split_indx);
                sepkey.mv_size = node->mn_ksize;
                sepkey.mv_data = NODEKEY(node);
        }
@@ -3386,20 +3379,24 @@ newsep:
                return rc;
        }
        if (rc != MDB_SUCCESS) {
-               free(copy);
                return rc;
        }
 
-       for (i = j = 0; i <= NUMKEYS(copy); j++) {
-               if (i < split_indx) {
-                       /* Re-insert in left sibling. */
-                       pdp = mdp;
-               } else {
-                       /* Insert in right sibling. */
-                       if (i == split_indx)
-                               /* Reset insert index for right sibling. */
-                               j = (i == newindx && ins_new);
-                       pdp = rdp;
+       /* Move half of the keys to the right sibling. */
+       if ((copy = malloc(txn->mt_env->me_psize)) == NULL)
+               return ENOMEM;
+
+       copy->mp_pgno  = mdp->p.mp_pgno;
+       copy->mp_flags = mdp->p.mp_flags;
+       copy->mp_lower = PAGEHDRSZ;
+       copy->mp_upper = txn->mt_env->me_psize;
+       cptr = copy;
+       for (i = j = 0; i <= nkeys; j++) {
+               if (i == split_indx) {
+               /* Insert in right sibling. */
+               /* Reset insert index for right sibling. */
+                       j = (i == newindx && ins_new);
+                       cptr = &rdp->p;
                }
 
                if (i == newindx && !ins_new) {
@@ -3417,11 +3414,12 @@ newsep:
 
                        /* Update page and index for the new key. */
                        *newindxp = j;
-                       *mpp = &pdp->p;
-               } else if (i == NUMKEYS(copy)) {
+                       if (cptr == &rdp->p)
+                               *mpp = cptr;
+               } else if (i == nkeys) {
                        break;
                } else {
-                       node = NODEPTR(copy, i);
+                       node = NODEPTR(&mdp->p, i);
                        rkey.mv_data = NODEKEY(node);
                        rkey.mv_size = node->mn_ksize;
                        if (IS_LEAF(&mdp->p)) {
@@ -3439,8 +3437,15 @@ newsep:
                        rkey.mv_size = 0;
                }
 
-               rc = mdb_add_node(txn, dbi, &pdp->p, j, &rkey, &rdata, pgno,flags);
+               rc = mdb_add_node(txn, dbi, cptr, j, &rkey, &rdata, pgno, flags);
        }
+       nkeys = NUMKEYS(copy);
+       for (i=0; i<nkeys; i++)
+               mdp->p.mp_ptrs[i] = copy->mp_ptrs[i];
+       mdp->p.mp_lower = copy->mp_lower;
+       mdp->p.mp_upper = copy->mp_upper;
+       memcpy(NODEPTR(&mdp->p, nkeys-1), NODEPTR(copy, nkeys-1),
+               txn->mt_env->me_psize - copy->mp_upper);
 
        free(copy);
        return rc;