ITS#7229 more mdb_page_split tweaks

Also add mdb_debug/mdb_debug_start to toggle debug output at runtime

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index eddeb5e8993c0f46c39bf66d6ac17d5c5ddbaad5..482bb6243dabaf4b80ecea1dabe0b1ec08af1fc1 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -259,9 +259,12 @@ typedef ID txnid_t;
 #if !(__STDC_VERSION__ >= 199901L || defined(__GNUC__))
 # define DPRINTF       (void)  /* Vararg macros may be unsupported */
 #elif MDB_DEBUG
+static int mdb_debug;
+static int mdb_debug_start;
+
        /**     Print a debug message with printf formatting. */
 # define DPRINTF(fmt, ...)     /**< Requires 2 or more args */ \
-       fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)
+       if (mdb_debug) fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)
 #else
 # define DPRINTF(fmt, ...)     ((void) 0)
 #endif
@@ -1576,6 +1579,10 @@ mdb_txn_renew0(MDB_txn *txn)
                if (env->me_wtxnid < txn->mt_txnid)
                        mt_dbflag = DB_STALE;
                txn->mt_txnid++;
+#if MDB_DEBUG
+               if (txn->mt_txnid == mdb_debug_start)
+                       mdb_debug = 1;
+#endif
                txn->mt_toggle = env->me_txns->mti_me_toggle;
                txn->mt_u.dirty_list = env->me_dirty_list;
                txn->mt_u.dirty_list[0].mid = 0;
@@ -5765,43 +5772,45 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno
         * When the size of the data items is much smaller than
         * one-half of a page, this check is irrelevant.
         */
-       if (IS_LEAF(mp) && nkeys < 16) {
+       if (IS_LEAF(mp)) {
                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) {
-                       psize = nsize;
-                       newpos = 0;
-                       for (i=0; i<split_indx; i++) {
-                               node = NODEPTR(mp, i);
-                               psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
-                               if (F_ISSET(node->mn_flags, F_BIGDATA))
-                                       psize += sizeof(pgno_t);
-                               else
-                                       psize += NODEDSZ(node);
-                               psize += psize & 1;
-                               if (psize > pmax) {
-                                       if (i == split_indx - 1 && newindx == split_indx)
-                                               newpos = 1;
+               if ((nkeys < 20) || (nsize > pmax/4)) {
+                       if (newindx <= split_indx) {
+                               psize = nsize;
+                               newpos = 0;
+                               for (i=0; i<split_indx; i++) {
+                                       node = NODEPTR(mp, i);
+                                       psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
+                                       if (F_ISSET(node->mn_flags, F_BIGDATA))
+                                               psize += sizeof(pgno_t);
                                        else
-                                               split_indx = i;
-                                       break;
+                                               psize += NODEDSZ(node);
+                                       psize += psize & 1;
+                                       if (psize > pmax) {
+                                               if (i == split_indx - 1 && newindx == split_indx)
+                                                       newpos = 1;
+                                               else
+                                                       split_indx = i;
+                                               break;
+                                       }
                                }
-                       }
-               } else {
-                       psize = nsize;
-                       for (i=nkeys-1; i>=split_indx; i--) {
-                               node = NODEPTR(mp, i);
-                               psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
-                               if (F_ISSET(node->mn_flags, F_BIGDATA))
-                                       psize += sizeof(pgno_t);
-                               else
-                                       psize += NODEDSZ(node);
-                               psize += psize & 1;
-                               if (psize > pmax) {
-                                       split_indx = i+1;
-                                       break;
+                       } else {
+                               psize = nsize;
+                               for (i=nkeys-1; i>=split_indx; i--) {
+                                       node = NODEPTR(mp, i);
+                                       psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
+                                       if (F_ISSET(node->mn_flags, F_BIGDATA))
+                                               psize += sizeof(pgno_t);
+                                       else
+                                               psize += NODEDSZ(node);
+                                       psize += psize & 1;
+                                       if (psize > pmax) {
+                                               split_indx = i+1;
+                                               break;
+                                       }
                                }
                        }
                }
@@ -5918,6 +5927,7 @@ newsep:
                }
 
                rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
+               if (rc) break;
        }
 
        nkeys = NUMKEYS(copy);