ITS#7210 partial fix

Allow pages from free list to be used when growing the free list.
(Yes, this is self-referential...)

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index e69dcf5522b0e56ee770d16b3e75990b964ab9f2..3ac46d006b112d45010e96535f0c8535ae8302a5 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -941,6 +941,8 @@ struct MDB_env {
        unsigned int    me_psize;       /**< size of a page, from #GET_PAGESIZE */
        unsigned int    me_db_toggle;   /**< which DB table is current */
        txnid_t         me_wtxnid;              /**< ID of last txn we committed */
+       txnid_t         me_pgfirst;             /**< ID of first old page record we used */
+       txnid_t         me_pglast;              /**< ID of last old page record we used */
        MDB_dbx         *me_dbxs;               /**< array of static DB info */
        MDB_db          *me_dbs[2];             /**< two arrays of MDB_db info */
        MDB_oldpages *me_pghead;        /**< list of old page records */
@@ -1157,17 +1159,32 @@ mdb_page_alloc(MDB_cursor *mc, int num)
 
        if (txn->mt_txnid > 2) {
 
-               if (!txn->mt_env->me_pghead && mc->mc_dbi != FREE_DBI &&
+               if (!txn->mt_env->me_pghead &&
                        txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
                        /* See if there's anything in the free DB */
                        MDB_cursor m2;
                        MDB_node *leaf;
-                       txnid_t *kptr, oldest;
+                       MDB_val data;
+                       txnid_t *kptr, oldest, last;
 
                        mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
-                       mdb_page_search(&m2, NULL, 0);
-                       leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
-                       kptr = (txnid_t *)NODEKEY(leaf);
+                       if (!txn->mt_env->me_pgfirst) {
+                               mdb_page_search(&m2, NULL, 0);
+                               leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
+                               kptr = (txnid_t *)NODEKEY(leaf);
+                               last = *kptr;
+                       } else {
+                               MDB_val key;
+                               int rc, exact = 0;
+                               last = txn->mt_env->me_pglast + 1;
+                               leaf = NULL;
+                               key.mv_data = &last;
+                               key.mv_size = sizeof(last);
+                               rc = mdb_cursor_set(&m2, &key, &data, MDB_SET, &exact);
+                               if (rc)
+                                       goto none;
+                               last = *(txnid_t *)key.mv_data;
+                       }
 
                        {
                                unsigned int i;
@@ -1179,18 +1196,22 @@ mdb_page_alloc(MDB_cursor *mc, int num)
                                }
                        }
 
-                       if (oldest > *kptr) {
+                       if (oldest > last) {
                                /* It's usable, grab it.
                                 */
                                MDB_oldpages *mop;
-                               MDB_val data;
                                pgno_t *idl;
 
-                               mdb_node_read(txn, leaf, &data);
+                               if (!txn->mt_env->me_pgfirst) {
+                                       mdb_node_read(txn, leaf, &data);
+                               }
                                idl = (ID *) data.mv_data;
                                mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(idl) - sizeof(pgno_t));
                                mop->mo_next = txn->mt_env->me_pghead;
-                               mop->mo_txnid = *kptr;
+                               mop->mo_txnid = last;
+                               txn->mt_env->me_pglast = last;
+                               if (!txn->mt_env->me_pgfirst)
+                                       txn->mt_env->me_pgfirst = last;
                                txn->mt_env->me_pghead = mop;
                                memcpy(mop->mo_pages, idl, MDB_IDL_SIZEOF(idl));
 
@@ -1204,12 +1225,12 @@ mdb_page_alloc(MDB_cursor *mc, int num)
                                        }
                                }
 #endif
-                               /* drop this IDL from the DB */
-                               m2.mc_ki[m2.mc_top] = 0;
-                               m2.mc_flags = C_INITIALIZED;
-                               mdb_cursor_del(&m2, 0);
+                               if (mop->mo_txnid == 87869 && txn->mt_txnid == 87879) {
+                                       int i=1;
+                               }
                        }
                }
+none:
                if (txn->mt_env->me_pghead) {
                        MDB_oldpages *mop = txn->mt_env->me_pghead;
                        if (num > 1) {
@@ -1678,6 +1699,8 @@ mdb_txn_reset0(MDB_txn *txn)
                        txn->mt_env->me_pghead = mop->mo_next;
                        free(mop);
                }
+               txn->mt_env->me_pgfirst = 0;
+               txn->mt_env->me_pglast = 0;
 
                env->me_txn = NULL;
                /* The writer mutex was locked in mdb_txn_begin. */
@@ -1836,6 +1859,24 @@ mdb_txn_commit(MDB_txn *txn)
                /* make sure first page of freeDB is touched and on freelist */
                mdb_page_search(&mc, NULL, 1);
        }
+
+       /* Delete IDLs we used from the free list */
+       if (env->me_pgfirst) {
+               txnid_t cur;
+               MDB_val key;
+               int exact = 0;
+
+               key.mv_size = sizeof(cur);
+               for (cur = env->me_pgfirst; cur <= env->me_pglast; cur++) {
+                       key.mv_data = &cur;
+
+                       mdb_cursor_set(&mc, &key, NULL, MDB_SET, &exact);
+                       mdb_cursor_del(&mc, 0);
+               }
+               env->me_pgfirst = 0;
+               env->me_pglast = 0;
+       }
+
        /* save to free list */
        if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
                MDB_val key, data;
@@ -1882,14 +1923,24 @@ mdb_txn_commit(MDB_txn *txn)
        if (env->me_pghead) {
                MDB_val key, data;
                MDB_oldpages *mop;
+               pgno_t orig;
 
                mop = env->me_pghead;
-               env->me_pghead = NULL;
                key.mv_size = sizeof(pgno_t);
                key.mv_data = &mop->mo_txnid;
                data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
                data.mv_data = mop->mo_pages;
+               orig = mop->mo_pages[0];
                mdb_cursor_put(&mc, &key, &data, 0);
+               /* could have been used again here */
+               if (mop->mo_pages[0] != orig) {
+                       data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
+                       data.mv_data = mop->mo_pages;
+                       mdb_cursor_put(&mc, &key, &data, 0);
+                       env->me_pgfirst = 0;
+                       env->me_pglast = 0;
+               }
+               env->me_pghead = NULL;
                free(mop);
        }