API change, consistency check

mdb_close() takes an env, not a txn.
Also, add check for stale DB records (in case some other process
wrote to the DB last).

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index 8a877c7..9496914 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -691,9 +691,6 @@ typedef struct MDB_meta {
        /** Auxiliary DB info.
         *      The information here is mostly static/read-only. There is
         *      only a single copy of this record in the environment.
-        *      The \b md_dirty flag is not read-only, but only a write
-        *      transaction can ever update it, and only write transactions
-        *      need to worry about it.
         */
 typedef struct MDB_dbx {
        MDB_val         md_name;                /**< name of the database */
@@ -701,8 +698,6 @@ typedef struct MDB_dbx {
        MDB_cmp_func    *md_dcmp;       /**< function for comparing data items */
        MDB_rel_func    *md_rel;        /**< user relocate function */
        void            *md_relctx;             /**< user-provided context for md_rel */
-       MDB_dbi md_parent;                      /**< parent DB of a sub-DB */
-       unsigned int    md_dirty;       /**< TRUE if DB was written in this txn */
 } MDB_dbx;
 
        /** A database transaction.
@@ -728,6 +723,15 @@ struct MDB_txn {
        MDB_dbx         *mt_dbxs;
        /** Array of MDB_db records for each known DB */
        MDB_db          *mt_dbs;
+/** @defgroup mt_dbflag        Transaction DB Flags
+ *     @ingroup internal
+ * @{
+ */
+#define DB_DIRTY       0x01            /**< DB was written in this txn */
+#define DB_STALE       0x02            /**< DB record is older than txnID */
+/** @} */
+       /** Array of flags for each DB */
+       unsigned char   *mt_dbflags;
        /**     Number of DB records in use. This number only ever increments;
         *      we don't decrement it when individual DB handles are closed.
         */
@@ -767,6 +771,8 @@ struct MDB_cursor {
        MDB_db          *mc_db;
        /** The database auxiliary record for this cursor */
        MDB_dbx         *mc_dbx;
+       /** The @ref mt_dbflag for this database */
+       unsigned char   *mc_dbflag;
        unsigned short  mc_snum;        /**< number of pushed pages */
        unsigned short  mc_top;         /**< index of top page, mc_snum-1 */
 /** @defgroup mdb_cursor       Cursor Flags
@@ -794,6 +800,8 @@ typedef struct MDB_xcursor {
        MDB_db  mx_db;
        /**     The auxiliary DB record for this Dup DB */
        MDB_dbx mx_dbx;
+       /** The @ref mt_dbflag for this Dup DB */
+       unsigned char mx_dbflag;
 } MDB_xcursor;
 
        /** A set of pages freed by an earlier transaction. */
@@ -830,6 +838,7 @@ struct MDB_env {
        pgno_t          me_maxpg;               /**< me_mapsize / me_psize */
        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 */
        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 */
@@ -1167,6 +1176,7 @@ static inline int
 mdb_txn_renew0(MDB_txn *txn)
 {
        MDB_env *env = txn->mt_env;
+       char mt_dbflag = 0;
 
        if (txn->mt_flags & MDB_TXN_RDONLY) {
                MDB_reader *r = pthread_getspecific(env->me_txkey);
@@ -1191,14 +1201,22 @@ mdb_txn_renew0(MDB_txn *txn)
                        r = &env->me_txns->mti_readers[i];
                        pthread_setspecific(env->me_txkey, r);
                }
-               txn->mt_txnid = env->me_txns->mti_txnid;
                txn->mt_toggle = env->me_txns->mti_me_toggle;
+               txn->mt_txnid = env->me_txns->mti_txnid;
+               /* This happens if a different process was the
+                * last writer to the DB.
+                */
+               if (env->me_wtxnid < txn->mt_txnid)
+                       mt_dbflag = DB_STALE;
                r->mr_txnid = txn->mt_txnid;
                txn->mt_u.reader = r;
        } else {
                LOCK_MUTEX_W(env);
 
-               txn->mt_txnid = env->me_txns->mti_txnid+1;
+               txn->mt_txnid = env->me_txns->mti_txnid;
+               if (env->me_wtxnid < txn->mt_txnid)
+                       mt_dbflag = DB_STALE;
+               txn->mt_txnid++;
                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;
@@ -1218,6 +1236,8 @@ mdb_txn_renew0(MDB_txn *txn)
                        (txn->mt_numdbs - 2) * sizeof(MDB_db));
        LAZY_RWLOCK_UNLOCK(&env->me_dblock);
 
+       memset(txn->mt_dbflags, mt_dbflag, env->me_numdbs);
+
        return MDB_SUCCESS;
 }
 
@@ -1253,7 +1273,8 @@ mdb_txn_begin(MDB_env *env, unsigned int flags, MDB_txn **ret)
                DPUTS("environment had fatal error, must shutdown!");
                return MDB_PANIC;
        }
-       if ((txn = calloc(1, sizeof(MDB_txn) + env->me_maxdbs * sizeof(MDB_db))) == NULL) {
+       if ((txn = calloc(1, sizeof(MDB_txn) +
+               env->me_maxdbs * (sizeof(MDB_db)+1))) == NULL) {
                DPRINTF("calloc: %s", strerror(ErrCode()));
                return ENOMEM;
        }
@@ -1261,6 +1282,7 @@ mdb_txn_begin(MDB_env *env, unsigned int flags, MDB_txn **ret)
        if (flags & MDB_RDONLY) {
                txn->mt_flags |= MDB_TXN_RDONLY;
        }
+       txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs);
        txn->mt_env = env;
 
        rc = mdb_txn_renew0(txn);
@@ -1289,7 +1311,6 @@ mdb_txn_reset0(MDB_txn *txn)
        } else {
                MDB_oldpages *mop;
                MDB_page *dp;
-               MDB_dbi dbi;
                unsigned int i;
 
                /* return all dirty pages to dpage list */
@@ -1310,8 +1331,6 @@ mdb_txn_reset0(MDB_txn *txn)
                }
 
                env->me_txn = NULL;
-               for (dbi=2; dbi<env->me_numdbs; dbi++)
-                       env->me_dbxs[dbi].md_dirty = 0;
                /* The writer mutex was locked in mdb_txn_begin. */
                UNLOCK_MUTEX_W(env);
        }
@@ -1362,6 +1381,23 @@ mdb_txn_commit(MDB_txn *txn)
        env = txn->mt_env;
 
        if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
+               if (txn->mt_numdbs > env->me_numdbs) {
+                       /* update the DB tables */
+                       int toggle = !env->me_db_toggle;
+                       MDB_db *ip, *jp;
+                       MDB_dbi i;
+
+                       ip = &env->me_dbs[toggle][env->me_numdbs];
+                       jp = &txn->mt_dbs[env->me_numdbs];
+                       LAZY_RWLOCK_WRLOCK(&env->me_dblock);
+                       for (i = env->me_numdbs; i < txn->mt_numdbs; i++) {
+                               *ip++ = *jp++;
+                       }
+
+                       env->me_db_toggle = toggle;
+                       env->me_numdbs = txn->mt_numdbs;
+                       LAZY_RWLOCK_UNLOCK(&env->me_dblock);
+               }
                mdb_txn_abort(txn);
                return MDB_SUCCESS;
        }
@@ -1456,7 +1492,7 @@ mdb_txn_commit(MDB_txn *txn)
 
                mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
                for (i = 2; i < txn->mt_numdbs; i++) {
-                       if (txn->mt_dbxs[i].md_dirty) {
+                       if (txn->mt_dbflags[i] & DB_DIRTY) {
                                data.mv_data = &txn->mt_dbs[i];
                                mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
                        }
@@ -1578,6 +1614,7 @@ mdb_txn_commit(MDB_txn *txn)
        }
 
 done:
+       env->me_wtxnid = txn->mt_txnid;
        env->me_txn = NULL;
        /* update the DB tables */
        {
@@ -1594,10 +1631,6 @@ done:
                        ip++; jp++;
                }
 
-               for (i = 2; i < txn->mt_numdbs; i++) {
-                       if (txn->mt_dbxs[i].md_dirty)
-                               txn->mt_dbxs[i].md_dirty = 0;
-               }
                env->me_db_toggle = toggle;
                env->me_numdbs = txn->mt_numdbs;
                LAZY_RWLOCK_UNLOCK(&env->me_dblock);
@@ -2825,16 +2858,32 @@ mdb_page_search(MDB_cursor *mc, MDB_val *key, int modify)
        DPRINTF("db %u root page %zu has flags 0x%X",
                mc->mc_dbi, root, mc->mc_pg[0]->mp_flags);
 
-       if (modify) {
-               /* For sub-databases, update main root first */
-               if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) {
+       /* For sub-databases, update main root first */
+       if (mc->mc_dbi > MAIN_DBI) {
+               if ((*mc->mc_dbflag & DB_STALE) ||
+                       (modify && !(*mc->mc_dbflag & DB_DIRTY))) {
                        MDB_cursor mc2;
+                       unsigned char dbflag = 0;
                        mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
-                       rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 1);
+                       rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, modify);
                        if (rc)
                                return rc;
-                       mc->mc_dbx->md_dirty = 1;
+                       if (*mc->mc_dbflag & DB_STALE) {
+                               MDB_val data;
+                               int exact = 0;
+                               MDB_node *leaf = mdb_node_search(&mc2,
+                                       &mc->mc_dbx->md_name, &exact);
+                               if (!exact)
+                                       return MDB_NOTFOUND;
+                               mdb_node_read(mc->mc_txn, leaf, &data);
+                               memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
+                       }
+                       if (modify)
+                               dbflag = DB_DIRTY;
+                       *mc->mc_dbflag = dbflag;
                }
+       }
+       if (modify) {
                if (!F_ISSET(mc->mc_pg[0]->mp_flags, P_DIRTY)) {
                        if ((rc = mdb_page_touch(mc)))
                                return rc;
@@ -3475,13 +3524,13 @@ mdb_cursor_touch(MDB_cursor *mc)
 {
        int rc;
 
-       if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) {
+       if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
                MDB_cursor mc2;
                mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
                rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 1);
                if (rc)
                         return rc;
-               mc->mc_dbx->md_dirty = 1;
+               *mc->mc_dbflag = DB_DIRTY;
        }
        for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) {
                if (!F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) {
@@ -3502,7 +3551,7 @@ int
 mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
     unsigned int flags)
 {
-       MDB_node        *leaf;
+       MDB_node        *leaf = NULL;
        MDB_val xdata, *rdata, dkey;
        MDB_page        *fp;
        MDB_db dummy;
@@ -3536,7 +3585,7 @@ mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
                mdb_cursor_push(mc, np);
                mc->mc_db->md_root = np->mp_pgno;
                mc->mc_db->md_depth++;
-               mc->mc_dbx->md_dirty = 1;
+               *mc->mc_dbflag = DB_DIRTY;
                if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
                        == MDB_DUPFIXED)
                        np->mp_flags |= P_LEAF2;
@@ -4181,11 +4230,10 @@ mdb_xcursor_init0(MDB_cursor *mc)
        mx->mx_cursor.mc_db = &mx->mx_db;
        mx->mx_cursor.mc_dbx = &mx->mx_dbx;
        mx->mx_cursor.mc_dbi = mc->mc_dbi+1;
-       mx->mx_dbx.md_parent = mc->mc_dbi;
+       mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
        mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
        mx->mx_dbx.md_dcmp = NULL;
        mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
-       mx->mx_dbx.md_dirty = 0;
 }
 
 /** Final setup of a sorted-dups cursor.
@@ -4228,8 +4276,8 @@ mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
        }
        DPRINTF("Sub-db %u for db %u root page %zu", mx->mx_cursor.mc_dbi, mc->mc_dbi,
                mx->mx_db.md_root);
-       if (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY))
-               mx->mx_dbx.md_dirty = 1;
+       mx->mx_dbflag = (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) ?
+               DB_DIRTY : 0;
        mx->mx_dbx.md_name.mv_data = NODEKEY(node);
        mx->mx_dbx.md_name.mv_size = node->mn_ksize;
        if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
@@ -4244,6 +4292,7 @@ mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
        mc->mc_txn = txn;
        mc->mc_db = &txn->mt_dbs[dbi];
        mc->mc_dbx = &txn->mt_dbxs[dbi];
+       mc->mc_dbflag = &txn->mt_dbflags[dbi];
        mc->mc_snum = 0;
        mc->mc_flags = 0;
        if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
@@ -5152,7 +5201,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
 {
        MDB_val key, data;
        MDB_dbi i;
-       int rc, dirty = 0;
+       int rc, dbflag = 0;
        size_t len;
 
        if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
@@ -5201,7 +5250,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
                dummy.md_flags = flags & 0xffff;
                mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
                rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
-               dirty = 1;
+               dbflag = DB_DIRTY;
        }
 
        /* OK, got info, add to table */
@@ -5209,8 +5258,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
                txn->mt_dbxs[txn->mt_numdbs].md_name.mv_data = strdup(name);
                txn->mt_dbxs[txn->mt_numdbs].md_name.mv_size = len;
                txn->mt_dbxs[txn->mt_numdbs].md_rel = NULL;
-               txn->mt_dbxs[txn->mt_numdbs].md_parent = MAIN_DBI;
-               txn->mt_dbxs[txn->mt_numdbs].md_dirty = dirty;
+               txn->mt_dbflags[txn->mt_numdbs] = dbflag;
                memcpy(&txn->mt_dbs[txn->mt_numdbs], data.mv_data, sizeof(MDB_db));
                *dbi = txn->mt_numdbs;
                txn->mt_env->me_dbs[0][txn->mt_numdbs] = txn->mt_dbs[txn->mt_numdbs];
@@ -5230,17 +5278,35 @@ int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
        return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
 }
 
-void mdb_close(MDB_txn *txn, MDB_dbi dbi)
+void mdb_close(MDB_env *env, MDB_dbi dbi)
 {
        char *ptr;
-       if (dbi <= MAIN_DBI || dbi >= txn->mt_numdbs)
+       if (dbi <= MAIN_DBI || dbi >= env->me_numdbs)
                return;
-       ptr = txn->mt_dbxs[dbi].md_name.mv_data;
-       txn->mt_dbxs[dbi].md_name.mv_data = NULL;
-       txn->mt_dbxs[dbi].md_name.mv_size = 0;
+       ptr = env->me_dbxs[dbi].md_name.mv_data;
+       env->me_dbxs[dbi].md_name.mv_data = NULL;
+       env->me_dbxs[dbi].md_name.mv_size = 0;
        free(ptr);
 }
 
+int mdb_drop(MDB_env *env, MDB_dbi dbi)
+{
+       MDB_txn *txn;
+       int rc;
+
+       if (!env || !dbi || dbi >= env->me_numdbs)
+               return EINVAL;
+
+       if (env->me_txn)
+               return EBUSY;
+
+       rc = mdb_txn_begin(env, 0, &txn);
+       if (rc)
+               return rc;
+
+
+}
+
 int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
 {
        if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)

diff --git a/libraries/libmdb/mdb.h b/libraries/libmdb/mdb.h
index b99ece7..04293d4 100644 (file)
--- a/libraries/libmdb/mdb.h
+++ b/libraries/libmdb/mdb.h
@@ -592,15 +592,34 @@ int  mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi);
 int  mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *stat);
 
        /** Close a database handle.
-        * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+        * This call is not mutex protected. Handles should only be closed by
+        * a single thread, and only if no other threads are going to reference
+        * the database handle any further.
+        * @param[in] env An environment handle returned by #mdb_env_create()
+        * @param[in] dbi A database handle returned by #mdb_open()
+        */
+void mdb_close(MDB_env *env, MDB_dbi dbi);
+
+       /** Delete a database and free all its pages.
+        * This function acquires its own write transaction to perform its
+        * work, so it must not be called if there is already an open write
+        * transaction in the environment. The database handle will also be
+        * closed as part of this operation.
+        * @param[in] env An environment handle returned by #mdb_env_create()
         * @param[in] dbi A database handle returned by #mdb_open()
+        * @return A non-zero error value on failure and 0 on success. Some possible
+        * errors are:
+        * <ul>
+        *      <li>EINVAL - an invalid parameter was specified.
+        *      <li>EBUSY - there is already a write transaction.
+        * </ul>
         */
-void mdb_close(MDB_txn *txn, MDB_dbi dbi);
+int  mdb_drop(MDB_env *env, MDB_dbi dbi);
 
        /** Set a custom key comparison function for a database.
         * The comparison function is called whenever it is necessary to compare a
         * key specified by the application with a key currently stored in the database.
-        * If no comparison function is specified, and no special key flags were specified
+        * If no comparison function is specified, and no speAGAINcial key flags were specified
         * with #mdb_open(), the keys are compared lexically, with shorter keys collating
         * before longer keys.
         * @warning This function must be called before any data access functions are used,

diff --git a/libraries/libmdb/mdb_stat.c b/libraries/libmdb/mdb_stat.c
index 4bcdb92..931ec61 100644 (file)
--- a/libraries/libmdb/mdb_stat.c
+++ b/libraries/libmdb/mdb_stat.c
@@ -56,7 +56,7 @@ int main(int argc,char * argv[])
        printf("Leaf pages: %zu\n", mst.ms_leaf_pages);
        printf("Overflow pages: %zu\n", mst.ms_overflow_pages);
        printf("Entries: %zu\n", mst.ms_entries);
-       mdb_close(txn, dbi);
+       mdb_close(env, dbi);
        mdb_txn_abort(txn);
        mdb_env_close(env);
 

diff --git a/libraries/libmdb/mtest.c b/libraries/libmdb/mtest.c
index 8f2ecbf..89f0ac4 100644 (file)
--- a/libraries/libmdb/mtest.c
+++ b/libraries/libmdb/mtest.c
@@ -146,7 +146,7 @@ int main(int argc,char * argv[])
                }
 #endif
                mdb_cursor_close(cursor);
-               mdb_close(txn, dbi);
+               mdb_close(env, dbi);
 
                mdb_txn_abort(txn);
                mdb_env_close(env);

diff --git a/libraries/libmdb/mtest2.c b/libraries/libmdb/mtest2.c
index 5aeb97d..17c1ecf 100644 (file)
--- a/libraries/libmdb/mtest2.c
+++ b/libraries/libmdb/mtest2.c
@@ -108,7 +108,7 @@ int main(int argc,char * argv[])
                        (int) data.mv_size, (char *) data.mv_data);
        }
        mdb_cursor_close(cursor);
-       mdb_close(txn, dbi);
+       mdb_close(env, dbi);
 
        mdb_txn_abort(txn);
        mdb_env_close(env);

diff --git a/libraries/libmdb/mtest3.c b/libraries/libmdb/mtest3.c
index 467a123..43e3481 100644 (file)
--- a/libraries/libmdb/mtest3.c
+++ b/libraries/libmdb/mtest3.c
@@ -118,7 +118,7 @@ int main(int argc,char * argv[])
                        (int) data.mv_size, (char *) data.mv_data);
        }
        mdb_cursor_close(cursor);
-       mdb_close(txn, dbi);
+       mdb_close(env, dbi);
 
        mdb_txn_abort(txn);
        mdb_env_close(env);

diff --git a/libraries/libmdb/mtest4.c b/libraries/libmdb/mtest4.c
index d3a7877..821055a 100644 (file)
--- a/libraries/libmdb/mtest4.c
+++ b/libraries/libmdb/mtest4.c
@@ -152,7 +152,7 @@ int main(int argc,char * argv[])
                        (int) data.mv_size, (char *) data.mv_data);
        }
        mdb_cursor_close(cursor);
-       mdb_close(txn, dbi);
+       mdb_close(env, dbi);
 
        mdb_txn_abort(txn);
        mdb_env_close(env);

diff --git a/libraries/libmdb/mtest5.c b/libraries/libmdb/mtest5.c
index 472b100..5fb6bb0 100644 (file)
--- a/libraries/libmdb/mtest5.c
+++ b/libraries/libmdb/mtest5.c
@@ -120,7 +120,7 @@ int main(int argc,char * argv[])
                        (int) data.mv_size, (char *) data.mv_data);
        }
        mdb_cursor_close(cursor);
-       mdb_close(txn, dbi);
+       mdb_close(env, dbi);
 
        mdb_txn_abort(txn);
        mdb_env_close(env);