diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c index ffbfefc8dd..e70e46d572 100644 --- a/libraries/libmdb/mdb.c +++ b/libraries/libmdb/mdb.c @@ -5638,7 +5638,7 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno unsigned int nflags) { unsigned int flags; - int rc = MDB_SUCCESS, ins_new = 0, new_root = 0; + int rc = MDB_SUCCESS, ins_new = 0, new_root = 0, newpos = 1; indx_t newindx; pgno_t pgno = 0; unsigned int i, j, split_indx, nkeys, pmax; @@ -5751,15 +5751,22 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno } /* For leaf pages, check the split point based on what - * fits where, since otherwise add_node can fail. + * fits where, since otherwise mdb_node_add can fail. + * + * This check is only needed when the data items are + * relatively large, such that being off by one will + * make the difference between success or failure. + * When the size of the data items is much smaller than + * one-half of a page, this check is irrelevant. */ - if (IS_LEAF(mp)) { + if (IS_LEAF(mp) && nkeys < 4) { unsigned int psize, nsize; /* Maximum free space in an empty page */ pmax = mc->mc_txn->mt_env->me_psize - PAGEHDRSZ; nsize = mdb_leaf_size(mc->mc_txn->mt_env, newkey, newdata); - if (newindx < split_indx) { + if (newindx <= split_indx) { psize = nsize; + newpos = 0; for (i=0; i pmax) { - split_indx = i; + if (i == split_indx - 1 && newindx == split_indx) + newpos = 1; + else + split_indx = i; break; } } @@ -5792,8 +5802,11 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno } /* First find the separating key between the split pages. + * The case where newindx == split_indx is ambiguous; the + * new item could go to the new page or stay on the original + * page. If newpos == 1 it goes to the new page. */ - if (newindx == split_indx) { + if (newindx == split_indx && newpos) { sepkey.mv_size = newkey->mv_size; sepkey.mv_data = newkey->mv_data; } else { @@ -5856,8 +5869,10 @@ newsep: if (i == split_indx) { /* Insert in right sibling. */ /* Reset insert index for right sibling. */ - j = (i == newindx && ins_new); - mc->mc_pg[mc->mc_top] = rp; + if (i != newindx || (newpos ^ ins_new)) { + j = 0; + mc->mc_pg[mc->mc_top] = rp; + } } if (i == newindx && !ins_new) { @@ -5872,9 +5887,7 @@ newsep: ins_new = 1; - /* Update page and index for the new key. */ - if (!newindx) - mc->mc_pg[mc->mc_top] = copy; + /* Update index for the new key. */ mc->mc_ki[mc->mc_top] = j; } else if (i == nkeys) { break; @@ -5910,7 +5923,7 @@ newsep: mc->mc_txn->mt_env->me_psize - copy->mp_upper); /* reset back to original page */ - if (!newindx || (newindx < split_indx)) { + if (newindx < split_indx || (!newpos && newindx == split_indx)) { mc->mc_pg[mc->mc_top] = mp; if (nflags & MDB_RESERVE) { node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);