diff --git a/external/db_drivers/liblmdb64/CHANGES b/external/db_drivers/liblmdb64/CHANGES
index cf12f2ee..957742e7 100644
--- a/external/db_drivers/liblmdb64/CHANGES
+++ b/external/db_drivers/liblmdb64/CHANGES
@@ -1,18 +1,31 @@
 LMDB 0.9 Change Log
 
-LMDB 0.9.15 Release Engineering
+LMDB 0.9.15 Release (2015/06/19)
 	Fix txn init (ITS#7961,#7987)
 	Fix MDB_PREV_DUP (ITS#7955,#7671)
 	Fix compact of empty env (ITS#7956)
+	Fix mdb_copy file mode
+	Fix mdb_env_close() after failed mdb_env_open()
+	Fix mdb_rebalance collapsing root (ITS#8062)
 	Fix mdb_load with large values (ITS#8066)
+	Fix to retry writes on EINTR (ITS#8106)
+	Fix mdb_cursor_del on empty DB (ITS#8109)
+	Fix MDB_INTEGERDUP key compare (ITS#8117)
+	Fix error handling (ITS#7959,#8157,etc.)
+	Fix race conditions (ITS#7969,7970)
 	Added workaround for fdatasync bug in ext3fs
 	Build
 		Don't use -fPIC for static lib
 		Update .gitignore (ITS#7952,#7953)
-		Cleanup for "make test" (ITS#7841)
+		Cleanup for "make test" (ITS#7841), "make clean", mtest*.c
 		Misc. Android/Windows cleanup
 	Documentation
 		Fix MDB_APPEND doc
+		Fix MDB_MAXKEYSIZE doc (ITS#8156)
+		Fix mdb_cursor_put,mdb_cursor_del EACCES description
+		Fix mdb_env_sync(MDB_RDONLY env) doc (ITS#8021)
+		Clarify MDB_WRITEMAP doc (ITS#8021)
+		Clarify mdb_env_open doc
 		Clarify mdb_dbi_open doc
 
 LMDB 0.9.14 Release (2014/09/20)
diff --git a/external/db_drivers/liblmdb64/lmdb.h b/external/db_drivers/liblmdb64/lmdb.h
index 117f16ea..2f523579 100644
--- a/external/db_drivers/liblmdb64/lmdb.h
+++ b/external/db_drivers/liblmdb64/lmdb.h
@@ -184,7 +184,7 @@ typedef int mdb_filehandle_t;
 /** Library minor version */
 #define MDB_VERSION_MINOR	9
 /** Library patch version */
-#define MDB_VERSION_PATCH	14
+#define MDB_VERSION_PATCH	15
 
 /** Combine args a,b,c into a single integer for easy version comparisons */
 #define MDB_VERINT(a,b,c)	(((a) << 24) | ((b) << 16) | (c))
@@ -194,7 +194,7 @@ typedef int mdb_filehandle_t;
 	MDB_VERINT(MDB_VERSION_MAJOR,MDB_VERSION_MINOR,MDB_VERSION_PATCH)
 
 /** The release date of this library version */
-#define MDB_VERSION_DATE	"September 20, 2014"
+#define MDB_VERSION_DATE	"June 19, 2015"
 
 /** A stringifier for the version info */
 #define MDB_VERSTR(a,b,c,d)	"LMDB " #a "." #b "." #c ": (" d ")"
@@ -296,12 +296,12 @@ typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *rel
 #define MDB_REVERSEKEY	0x02
 	/** use sorted duplicates */
 #define MDB_DUPSORT		0x04
-	/** numeric keys in native byte order.
+	/** numeric keys in native byte order: either unsigned int or size_t.
 	 *  The keys must all be of the same size. */
 #define MDB_INTEGERKEY	0x08
 	/** with #MDB_DUPSORT, sorted dup items have fixed size */
 #define MDB_DUPFIXED	0x10
-	/** with #MDB_DUPSORT, dups are numeric in native byte order */
+	/** with #MDB_DUPSORT, dups are #MDB_INTEGERKEY-style integers */
 #define MDB_INTEGERDUP	0x20
 	/** with #MDB_DUPSORT, use reverse string dups */
 #define MDB_REVERSEDUP	0x40
@@ -588,8 +588,8 @@ int  mdb_env_create(MDB_env **env);
 	 *		reserved in that case.
 	 *		This flag may be changed at any time using #mdb_env_set_flags().
 	 * </ul>
-	 * @param[in] mode The UNIX permissions to set on created files. This parameter
-	 * is ignored on Windows.
+	 * @param[in] mode The UNIX permissions to set on created files and semaphores.
+	 * This parameter is ignored on Windows.
 	 * @return A non-zero error value on failure and 0 on success. Some possible
 	 * errors are:
 	 * <ul>
@@ -1021,14 +1021,16 @@ int  mdb_txn_renew(MDB_txn *txn);
 	 * The database handle may be discarded by calling #mdb_dbi_close().
 	 * The old database handle is returned if the database was already open.
 	 * The handle may only be closed once.
+	 *
 	 * The database handle will be private to the current transaction until
 	 * the transaction is successfully committed. If the transaction is
 	 * aborted the handle will be closed automatically.
-	 * After a successful commit the
-	 * handle will reside in the shared environment, and may be used
-	 * by other transactions. This function must not be called from
-	 * multiple concurrent transactions in the same process. A transaction
-	 * that uses this function must finish (either commit or abort) before
+	 * After a successful commit the handle will reside in the shared
+	 * environment, and may be used by other transactions.
+	 *
+	 * This function must not be called from multiple concurrent
+	 * transactions in the same process. A transaction that uses
+	 * this function must finish (either commit or abort) before
 	 * any other transaction in the process may use this function.
 	 *
 	 * To use named databases (with name != NULL), #mdb_env_set_maxdbs()
@@ -1050,9 +1052,9 @@ int  mdb_txn_renew(MDB_txn *txn);
 	 *		keys may have multiple data items, stored in sorted order.) By default
 	 *		keys must be unique and may have only a single data item.
 	 *	<li>#MDB_INTEGERKEY
-	 *		Keys are binary integers in native byte order. Setting this option
-	 *		requires all keys to be the same size, typically sizeof(int)
-	 *		or sizeof(size_t).
+	 *		Keys are binary integers in native byte order, either unsigned int
+	 *		or size_t, and will be sorted as such.
+	 *		The keys must all be of the same size.
 	 *	<li>#MDB_DUPFIXED
 	 *		This flag may only be used in combination with #MDB_DUPSORT. This option
 	 *		tells the library that the data items for this database are all the same
@@ -1060,8 +1062,8 @@ int  mdb_txn_renew(MDB_txn *txn);
 	 *		all data items are the same size, the #MDB_GET_MULTIPLE and #MDB_NEXT_MULTIPLE
 	 *		cursor operations may be used to retrieve multiple items at once.
 	 *	<li>#MDB_INTEGERDUP
-	 *		This option specifies that duplicate data items are also integers, and
-	 *		should be sorted as such.
+	 *		This option specifies that duplicate data items are binary integers,
+	 *		similar to #MDB_INTEGERKEY keys.
 	 *	<li>#MDB_REVERSEDUP
 	 *		This option specifies that duplicate data items should be compared as
 	 *		strings in reverse order.
@@ -1450,7 +1452,7 @@ int  mdb_cursor_get(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
 	 * <ul>
 	 *	<li>#MDB_MAP_FULL - the database is full, see #mdb_env_set_mapsize().
 	 *	<li>#MDB_TXN_FULL - the transaction has too many dirty pages.
-	 *	<li>EACCES - an attempt was made to modify a read-only database.
+	 *	<li>EACCES - an attempt was made to write in a read-only transaction.
 	 *	<li>EINVAL - an invalid parameter was specified.
 	 * </ul>
 	 */
@@ -1470,7 +1472,7 @@ int  mdb_cursor_put(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
 	 * @return A non-zero error value on failure and 0 on success. Some possible
 	 * errors are:
 	 * <ul>
-	 *	<li>EACCES - an attempt was made to modify a read-only database.
+	 *	<li>EACCES - an attempt was made to write in a read-only transaction.
 	 *	<li>EINVAL - an invalid parameter was specified.
 	 * </ul>
 	 */
diff --git a/external/db_drivers/liblmdb64/mdb.c b/external/db_drivers/liblmdb64/mdb.c
index c788b853..6bdf3151 100644
--- a/external/db_drivers/liblmdb64/mdb.c
+++ b/external/db_drivers/liblmdb64/mdb.c
@@ -446,12 +446,17 @@ static txnid_t mdb_debug_start;
 	/**	The version number for a database's lockfile format. */
 #define MDB_LOCK_VERSION	 1
 
-	/**	@brief The max size of a key we can write, or 0 for dynamic max.
+	/**	@brief The max size of a key we can write, or 0 for computed max.
 	 *
-	 *	Define this as 0 to compute the max from the page size.  511
-	 *	is default for backwards compat: liblmdb <= 0.9.10 can break
-	 *	when modifying a DB with keys/dupsort data bigger than its max.
-	 *	#MDB_DEVEL sets the default to 0.
+	 *	This macro should normally be left alone or set to 0.
+	 *	Note that a database with big keys or dupsort data cannot be
+	 *	reliably modified by a liblmdb which uses a smaller max.
+	 *	The default is 511 for backwards compat, or 0 when #MDB_DEVEL.
+	 *
+	 *	Other values are allowed, for backwards compat.  However:
+	 *	A value bigger than the computed max can break if you do not
+	 *	know what you are doing, and liblmdb <= 0.9.10 can break when
+	 *	modifying a DB with keys/dupsort data bigger than its max.
 	 *
 	 *	Data items in an #MDB_DUPSORT database are also limited to
 	 *	this size, since they're actually keys of a sub-DB.  Keys and
@@ -1245,6 +1250,13 @@ static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
 static MDB_cmp_func	mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
 /** @endcond */
 
+/** Compare two items pointing at size_t's of unknown alignment. */
+#ifdef MISALIGNED_OK
+# define mdb_cmp_clong mdb_cmp_long
+#else
+# define mdb_cmp_clong mdb_cmp_cint
+#endif
+
 #ifdef _WIN32
 static SECURITY_DESCRIPTOR mdb_null_sd;
 static SECURITY_ATTRIBUTES mdb_all_sa;
@@ -1558,7 +1570,12 @@ mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
 int
 mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
 {
-	return txn->mt_dbxs[dbi].md_dcmp(a, b);
+	MDB_cmp_func *dcmp = txn->mt_dbxs[dbi].md_dcmp;
+#if UINT_MAX < SIZE_MAX
+	if (dcmp == mdb_cmp_int && a->mv_size == sizeof(size_t))
+		dcmp = mdb_cmp_clong;
+#endif
+	return dcmp(a, b);
 }
 
 /** Allocate memory for a page.
@@ -2486,14 +2503,11 @@ mdb_txn_renew0(MDB_txn *txn)
 	MDB_env *env = txn->mt_env;
 	MDB_txninfo *ti = env->me_txns;
 	MDB_meta *meta;
-	unsigned int i, nr;
+	unsigned int i, nr, flags = txn->mt_flags;
 	uint16_t x;
 	int rc, new_notls = 0;
 
-	if (txn->mt_flags & MDB_TXN_RDONLY) {
-		/* Setup db info */
-		txn->mt_numdbs = env->me_numdbs;
-		txn->mt_dbxs = env->me_dbxs;	/* mostly static anyway */
+	if ((flags &= MDB_TXN_RDONLY) != 0) {
 		if (!ti) {
 			meta = env->me_metas[ mdb_env_pick_meta(env) ];
 			txn->mt_txnid = meta->mm_txnid;
@@ -2546,6 +2560,7 @@ mdb_txn_renew0(MDB_txn *txn)
 			txn->mt_u.reader = r;
 			meta = env->me_metas[txn->mt_txnid & 1];
 		}
+		txn->mt_dbxs = env->me_dbxs;	/* mostly static anyway */
 	} else {
 		if (ti) {
 			LOCK_MUTEX_W(env);
@@ -2556,14 +2571,11 @@ mdb_txn_renew0(MDB_txn *txn)
 			meta = env->me_metas[ mdb_env_pick_meta(env) ];
 			txn->mt_txnid = meta->mm_txnid;
 		}
-		/* Setup db info */
-		txn->mt_numdbs = env->me_numdbs;
 		txn->mt_txnid++;
 #if MDB_DEBUG
 		if (txn->mt_txnid == mdb_debug_start)
 			mdb_debug = 1;
 #endif
-		txn->mt_flags = 0;
 		txn->mt_child = NULL;
 		txn->mt_loose_pgs = NULL;
 		txn->mt_loose_count = 0;
@@ -2583,6 +2595,10 @@ mdb_txn_renew0(MDB_txn *txn)
 	/* Moved to here to avoid a data race in read TXNs */
 	txn->mt_next_pgno = meta->mm_last_pg+1;
 
+	txn->mt_flags = flags;
+
+	/* Setup db info */
+	txn->mt_numdbs = env->me_numdbs;
 	for (i=2; i<txn->mt_numdbs; i++) {
 		x = env->me_dbflags[i];
 		txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
@@ -3132,6 +3148,7 @@ mdb_page_flush(MDB_txn *txn, int keep)
 		/* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
 		if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE) {
 			if (n) {
+retry_write:
 				/* Write previous page(s) */
 #ifdef MDB_USE_PWRITEV
 				wres = pwritev(env->me_fd, iov, n, wpos);
@@ -3139,8 +3156,11 @@ mdb_page_flush(MDB_txn *txn, int keep)
 				if (n == 1) {
 					wres = pwrite(env->me_fd, iov[0].iov_base, wsize, wpos);
 				} else {
+retry_seek:
 					if (lseek(env->me_fd, wpos, SEEK_SET) == -1) {
 						rc = ErrCode();
+						if (rc == EINTR)
+							goto retry_seek;
 						DPRINTF(("lseek: %s", strerror(rc)));
 						return rc;
 					}
@@ -3150,6 +3170,8 @@ mdb_page_flush(MDB_txn *txn, int keep)
 				if (wres != wsize) {
 					if (wres < 0) {
 						rc = ErrCode();
+						if (rc == EINTR)
+							goto retry_write;
 						DPRINTF(("Write error: %s", strerror(rc)));
 					} else {
 						rc = EIO; /* TODO: Use which error code? */
@@ -3519,7 +3541,8 @@ mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
 	int len;
 #define DO_PWRITE(rc, fd, ptr, size, len, pos)	do { \
 	len = pwrite(fd, ptr, size, pos);	\
-	rc = (len >= 0); } while(0)
+	if (len == -1 && ErrCode() == EINTR) continue; \
+	rc = (len >= 0); break; } while(1)
 #endif
 
 	DPUTS("writing new meta page");
@@ -3624,6 +3647,7 @@ mdb_env_write_meta(MDB_txn *txn)
 	/* Write to the SYNC fd */
 	mfd = env->me_flags & (MDB_NOSYNC|MDB_NOMETASYNC) ?
 		env->me_fd : env->me_mfd;
+retry_write:
 #ifdef _WIN32
 	{
 		memset(&ov, 0, sizeof(ov));
@@ -3636,6 +3660,8 @@ mdb_env_write_meta(MDB_txn *txn)
 #endif
 	if (rc != len) {
 		rc = rc < 0 ? ErrCode() : EIO;
+		if (rc == EINTR)
+			goto retry_write;
 		DPUTS("write failed, disk error?");
 		/* On a failure, the pagecache still contains the new data.
 		 * Write some old data back, to prevent it from being used.
@@ -4761,7 +4787,11 @@ mdb_cmp_long(const MDB_val *a, const MDB_val *b)
 		*(size_t *)a->mv_data > *(size_t *)b->mv_data;
 }
 
-/** Compare two items pointing at aligned unsigned int's */
+/** Compare two items pointing at aligned unsigned int's.
+ *
+ *	This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp,
+ *	but #mdb_cmp_clong() is called instead if the data type is size_t.
+ */
 static int
 mdb_cmp_int(const MDB_val *a, const MDB_val *b)
 {
@@ -4799,13 +4829,6 @@ mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
 #endif
 }
 
-/** Compare two items pointing at size_t's of unknown alignment. */
-#ifdef MISALIGNED_OK
-# define mdb_cmp_clong mdb_cmp_long
-#else
-# define mdb_cmp_clong mdb_cmp_cint
-#endif
-
 /** Compare two items lexically */
 static int
 mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
@@ -5741,15 +5764,21 @@ set1:
 					return rc;
 			}
 		} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
-			MDB_val d2;
-			if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
+			MDB_val olddata;
+			MDB_cmp_func *dcmp;
+			if ((rc = mdb_node_read(mc->mc_txn, leaf, &olddata)) != MDB_SUCCESS)
 				return rc;
-			rc = mc->mc_dbx->md_dcmp(data, &d2);
+			dcmp = mc->mc_dbx->md_dcmp;
+#if UINT_MAX < SIZE_MAX
+			if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
+				dcmp = mdb_cmp_clong;
+#endif
+			rc = dcmp(data, &olddata);
 			if (rc) {
 				if (op == MDB_GET_BOTH || rc > 0)
 					return MDB_NOTFOUND;
 				rc = 0;
-				*data = d2;
+				*data = olddata;
 			}
 
 		} else {
@@ -6259,16 +6288,17 @@ more:
 
 			/* Was a single item before, must convert now */
 			if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+				MDB_cmp_func *dcmp;
 				/* Just overwrite the current item */
 				if (flags == MDB_CURRENT)
 					goto current;
-
+				dcmp = mc->mc_dbx->md_dcmp;
 #if UINT_MAX < SIZE_MAX
-				if (mc->mc_dbx->md_dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
-					mc->mc_dbx->md_dcmp = mdb_cmp_clong;
+				if (dcmp == mdb_cmp_int && olddata.mv_size == sizeof(size_t))
+					dcmp = mdb_cmp_clong;
 #endif
 				/* does data match? */
-				if (!mc->mc_dbx->md_dcmp(data, &olddata)) {
+				if (!dcmp(data, &olddata)) {
 					if (flags & MDB_NODUPDATA)
 						return MDB_KEYEXIST;
 					/* overwrite it */
@@ -7088,6 +7118,7 @@ mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
 	mc->mc_snum = 0;
 	mc->mc_top = 0;
 	mc->mc_pg[0] = 0;
+	mc->mc_ki[0] = 0;
 	mc->mc_flags = 0;
 	if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
 		mdb_tassert(txn, mx != NULL);
@@ -7717,12 +7748,12 @@ mdb_rebalance(MDB_cursor *mc)
 						m3 = m2;
 					if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
 					if (m3->mc_pg[0] == mp) {
-						m3->mc_snum--;
-						m3->mc_top--;
 						for (i=0; i<m3->mc_snum; i++) {
 							m3->mc_pg[i] = m3->mc_pg[i+1];
 							m3->mc_ki[i] = m3->mc_ki[i+1];
 						}
+						m3->mc_snum--;
+						m3->mc_top--;
 					}
 				}
 			}
@@ -7790,9 +7821,23 @@ mdb_rebalance(MDB_cursor *mc)
 		if (mc->mc_ki[ptop] == 0) {
 			rc = mdb_page_merge(&mn, mc);
 		} else {
+			MDB_cursor dummy;
 			oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);
 			mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
+			/* We want mdb_rebalance to find mn when doing fixups */
+			if (mc->mc_flags & C_SUB) {
+				dummy.mc_next = mc->mc_txn->mt_cursors[mc->mc_dbi];
+				mc->mc_txn->mt_cursors[mc->mc_dbi] = &dummy;
+				dummy.mc_xcursor = (MDB_xcursor *)&mn;
+			} else {
+				mn.mc_next = mc->mc_txn->mt_cursors[mc->mc_dbi];
+				mc->mc_txn->mt_cursors[mc->mc_dbi] = &mn;
+			}
 			rc = mdb_page_merge(mc, &mn);
+			if (mc->mc_flags & C_SUB)
+				mc->mc_txn->mt_cursors[mc->mc_dbi] = dummy.mc_next;
+			else
+				mc->mc_txn->mt_cursors[mc->mc_dbi] = mn.mc_next;
 			mdb_cursor_copy(&mn, mc);
 		}
 		mc->mc_flags &= ~C_EOF;
@@ -7819,6 +7864,13 @@ mdb_cursor_del0(MDB_cursor *mc)
 		MDB_cursor *m2, *m3;
 		MDB_dbi dbi = mc->mc_dbi;
 
+		/* DB is totally empty now, just bail out.
+		 * Other cursors adjustments were already done
+		 * by mdb_rebalance and aren't needed here.
+		 */
+		if (!mc->mc_snum)
+			return rc;
+
 		mp = mc->mc_pg[mc->mc_top];
 		nkeys = NUMKEYS(mp);
 
diff --git a/external/db_drivers/liblmdb64/mtest.c b/external/db_drivers/liblmdb64/mtest.c
index 66dabc75..9d15088b 100644
--- a/external/db_drivers/liblmdb64/mtest.c
+++ b/external/db_drivers/liblmdb64/mtest.c
@@ -45,19 +45,22 @@ int main(int argc,char * argv[])
 	    }
     
 		E(mdb_env_create(&env));
+		E(mdb_env_set_maxreaders(env, 1));
 		E(mdb_env_set_mapsize(env, 10485760));
 		E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP /*|MDB_NOSYNC*/, 0664));
+
 		E(mdb_txn_begin(env, NULL, 0, &txn));
-		E(mdb_open(txn, NULL, 0, &dbi));
+		E(mdb_dbi_open(txn, NULL, 0, &dbi));
    
 		key.mv_size = sizeof(int);
 		key.mv_data = sval;
-		data.mv_size = sizeof(sval);
-		data.mv_data = sval;
 
 		printf("Adding %d values\n", count);
 	    for (i=0;i<count;i++) {	
 			sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+			/* Set <data> in each iteration, since MDB_NOOVERWRITE may modify it */
+			data.mv_size = sizeof(sval);
+			data.mv_data = sval;
 			if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE))) {
 				j++;
 				data.mv_size = sizeof(sval);
@@ -68,7 +71,7 @@ int main(int argc,char * argv[])
 		E(mdb_txn_commit(txn));
 		E(mdb_env_stat(env, &mst));
 
-		E(mdb_txn_begin(env, NULL, 1, &txn));
+		E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 		E(mdb_cursor_open(txn, dbi, &cursor));
 		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
 			printf("key: %p %.*s, data: %p %.*s\n",
@@ -97,7 +100,7 @@ int main(int argc,char * argv[])
 		printf("Deleted %d values\n", j);
 
 		E(mdb_env_stat(env, &mst));
-		E(mdb_txn_begin(env, NULL, 1, &txn));
+		E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 		E(mdb_cursor_open(txn, dbi, &cursor));
 		printf("Cursor next\n");
 		while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -128,6 +131,7 @@ int main(int argc,char * argv[])
 				(int) key.mv_size,  (char *) key.mv_data,
 				(int) data.mv_size, (char *) data.mv_data);
 
+		mdb_cursor_close(cursor);
 		mdb_txn_abort(txn);
 
 		printf("Deleting with cursor\n");
@@ -164,9 +168,9 @@ int main(int argc,char * argv[])
 				data.mv_data, (int) data.mv_size, (char *) data.mv_data);
 		}
 		mdb_cursor_close(cursor);
-		mdb_close(env, dbi);
-
 		mdb_txn_abort(txn);
+
+		mdb_dbi_close(env, dbi);
 		mdb_env_close(env);
 
 	return 0;
diff --git a/external/db_drivers/liblmdb64/mtest2.c b/external/db_drivers/liblmdb64/mtest2.c
index 33e0e741..eacbe59d 100644
--- a/external/db_drivers/liblmdb64/mtest2.c
+++ b/external/db_drivers/liblmdb64/mtest2.c
@@ -47,20 +47,22 @@ int main(int argc,char * argv[])
 	}
 
 	E(mdb_env_create(&env));
+	E(mdb_env_set_maxreaders(env, 1));
 	E(mdb_env_set_mapsize(env, 10485760));
 	E(mdb_env_set_maxdbs(env, 4));
 	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+
 	E(mdb_txn_begin(env, NULL, 0, &txn));
-	E(mdb_open(txn, "id1", MDB_CREATE, &dbi));
+	E(mdb_dbi_open(txn, "id1", MDB_CREATE, &dbi));
    
 	key.mv_size = sizeof(int);
 	key.mv_data = sval;
-	data.mv_size = sizeof(sval);
-	data.mv_data = sval;
 
 	printf("Adding %d values\n", count);
 	for (i=0;i<count;i++) {	
 		sprintf(sval, "%03x %d foo bar", values[i], values[i]);
+		data.mv_size = sizeof(sval);
+		data.mv_data = sval;
 		if (RES(MDB_KEYEXIST, mdb_put(txn, dbi, &key, &data, MDB_NOOVERWRITE)))
 			j++;
 	}
@@ -68,7 +70,7 @@ int main(int argc,char * argv[])
 	E(mdb_txn_commit(txn));
 	E(mdb_env_stat(env, &mst));
 
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
 		printf("key: %p %.*s, data: %p %.*s\n",
@@ -97,7 +99,7 @@ int main(int argc,char * argv[])
 	printf("Deleted %d values\n", j);
 
 	E(mdb_env_stat(env, &mst));
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	printf("Cursor next\n");
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -114,10 +116,9 @@ int main(int argc,char * argv[])
 	}
 	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
 	mdb_cursor_close(cursor);
-	mdb_close(env, dbi);
-
 	mdb_txn_abort(txn);
-	mdb_env_close(env);
 
+	mdb_dbi_close(env, dbi);
+	mdb_env_close(env);
 	return 0;
 }
diff --git a/external/db_drivers/liblmdb64/mtest3.c b/external/db_drivers/liblmdb64/mtest3.c
index 85872c67..9db79e62 100644
--- a/external/db_drivers/liblmdb64/mtest3.c
+++ b/external/db_drivers/liblmdb64/mtest3.c
@@ -53,8 +53,9 @@ int main(int argc,char * argv[])
 	E(mdb_env_set_mapsize(env, 10485760));
 	E(mdb_env_set_maxdbs(env, 4));
 	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+
 	E(mdb_txn_begin(env, NULL, 0, &txn));
-	E(mdb_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
+	E(mdb_dbi_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
 
 	key.mv_size = sizeof(int);
 	key.mv_data = kval;
@@ -73,7 +74,7 @@ int main(int argc,char * argv[])
 	E(mdb_txn_commit(txn));
 	E(mdb_env_stat(env, &mst));
 
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
 		printf("key: %p %.*s, data: %p %.*s\n",
@@ -107,7 +108,7 @@ int main(int argc,char * argv[])
 	printf("Deleted %d values\n", j);
 
 	E(mdb_env_stat(env, &mst));
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	printf("Cursor next\n");
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -124,10 +125,9 @@ int main(int argc,char * argv[])
 	}
 	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
 	mdb_cursor_close(cursor);
-	mdb_close(env, dbi);
-
 	mdb_txn_abort(txn);
-	mdb_env_close(env);
 
+	mdb_dbi_close(env, dbi);
+	mdb_env_close(env);
 	return 0;
 }
diff --git a/external/db_drivers/liblmdb64/mtest4.c b/external/db_drivers/liblmdb64/mtest4.c
index fdcd46a3..6df890e2 100644
--- a/external/db_drivers/liblmdb64/mtest4.c
+++ b/external/db_drivers/liblmdb64/mtest4.c
@@ -51,8 +51,9 @@ int main(int argc,char * argv[])
 	E(mdb_env_set_mapsize(env, 10485760));
 	E(mdb_env_set_maxdbs(env, 4));
 	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+
 	E(mdb_txn_begin(env, NULL, 0, &txn));
-	E(mdb_open(txn, "id4", MDB_CREATE|MDB_DUPSORT|MDB_DUPFIXED, &dbi));
+	E(mdb_dbi_open(txn, "id4", MDB_CREATE|MDB_DUPSORT|MDB_DUPFIXED, &dbi));
 
 	key.mv_size = sizeof(int);
 	key.mv_data = kval;
@@ -72,7 +73,7 @@ int main(int argc,char * argv[])
 
 	/* there should be one full page of dups now.
 	 */
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
 		printf("key: %p %.*s, data: %p %.*s\n",
@@ -142,7 +143,7 @@ int main(int argc,char * argv[])
 	printf("Deleted %d values\n", j);
 
 	E(mdb_env_stat(env, &mst));
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	printf("Cursor next\n");
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -159,10 +160,9 @@ int main(int argc,char * argv[])
 	}
 	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
 	mdb_cursor_close(cursor);
-	mdb_close(env, dbi);
-
 	mdb_txn_abort(txn);
-	mdb_env_close(env);
 
+	mdb_dbi_close(env, dbi);
+	mdb_env_close(env);
 	return 0;
 }
diff --git a/external/db_drivers/liblmdb64/mtest5.c b/external/db_drivers/liblmdb64/mtest5.c
index 5295bce4..14e3c0da 100644
--- a/external/db_drivers/liblmdb64/mtest5.c
+++ b/external/db_drivers/liblmdb64/mtest5.c
@@ -53,8 +53,9 @@ int main(int argc,char * argv[])
 	E(mdb_env_set_mapsize(env, 10485760));
 	E(mdb_env_set_maxdbs(env, 4));
 	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+
 	E(mdb_txn_begin(env, NULL, 0, &txn));
-	E(mdb_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
+	E(mdb_dbi_open(txn, "id2", MDB_CREATE|MDB_DUPSORT, &dbi));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 
 	key.mv_size = sizeof(int);
@@ -75,7 +76,7 @@ int main(int argc,char * argv[])
 	E(mdb_txn_commit(txn));
 	E(mdb_env_stat(env, &mst));
 
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
 		printf("key: %p %.*s, data: %p %.*s\n",
@@ -109,7 +110,7 @@ int main(int argc,char * argv[])
 	printf("Deleted %d values\n", j);
 
 	E(mdb_env_stat(env, &mst));
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	printf("Cursor next\n");
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -126,10 +127,9 @@ int main(int argc,char * argv[])
 	}
 	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
 	mdb_cursor_close(cursor);
-	mdb_close(env, dbi);
-
 	mdb_txn_abort(txn);
-	mdb_env_close(env);
 
+	mdb_dbi_close(env, dbi);
+	mdb_env_close(env);
 	return 0;
 }
diff --git a/external/db_drivers/liblmdb64/mtest6.c b/external/db_drivers/liblmdb64/mtest6.c
index b351c1a0..ae3c7f26 100644
--- a/external/db_drivers/liblmdb64/mtest6.c
+++ b/external/db_drivers/liblmdb64/mtest6.c
@@ -31,7 +31,7 @@ int main(int argc,char * argv[])
 	int i = 0, j = 0, rc;
 	MDB_env *env;
 	MDB_dbi dbi;
-	MDB_val key, data;
+	MDB_val key, data, sdata;
 	MDB_txn *txn;
 	MDB_stat mst;
 	MDB_cursor *cursor;
@@ -46,33 +46,37 @@ int main(int argc,char * argv[])
 	E(mdb_env_set_mapsize(env, 10485760));
 	E(mdb_env_set_maxdbs(env, 4));
 	E(mdb_env_open(env, "./testdb", MDB_FIXEDMAP|MDB_NOSYNC, 0664));
+
 	E(mdb_txn_begin(env, NULL, 0, &txn));
-	E(mdb_open(txn, "id6", MDB_CREATE|MDB_INTEGERKEY, &dbi));
+	E(mdb_dbi_open(txn, "id6", MDB_CREATE|MDB_INTEGERKEY, &dbi));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	E(mdb_stat(txn, dbi, &mst));
 
 	sval = calloc(1, mst.ms_psize / 4);
 	key.mv_size = sizeof(long);
 	key.mv_data = &kval;
-	data.mv_size = mst.ms_psize / 4 - 30;
-	data.mv_data = sval;
+	sdata.mv_size = mst.ms_psize / 4 - 30;
+	sdata.mv_data = sval;
 
 	printf("Adding 12 values, should yield 3 splits\n");
 	for (i=0;i<12;i++) {
 		kval = i*5;
 		sprintf(sval, "%08x", kval);
+		data = sdata;
 		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
 	}
 	printf("Adding 12 more values, should yield 3 splits\n");
 	for (i=0;i<12;i++) {
 		kval = i*5+4;
 		sprintf(sval, "%08x", kval);
+		data = sdata;
 		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
 	}
 	printf("Adding 12 more values, should yield 3 splits\n");
 	for (i=0;i<12;i++) {
 		kval = i*5+1;
 		sprintf(sval, "%08x", kval);
+		data = sdata;
 		(void)RES(MDB_KEYEXIST, mdb_cursor_put(cursor, &key, &data, MDB_NOOVERWRITE));
 	}
 	E(mdb_cursor_get(cursor, &key, &data, MDB_FIRST));
@@ -110,7 +114,7 @@ int main(int argc,char * argv[])
 	printf("Deleted %d values\n", j);
 
 	E(mdb_env_stat(env, &mst));
-	E(mdb_txn_begin(env, NULL, 1, &txn));
+	E(mdb_txn_begin(env, NULL, MDB_RDONLY, &txn));
 	E(mdb_cursor_open(txn, dbi, &cursor));
 	printf("Cursor next\n");
 	while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
@@ -127,9 +131,9 @@ int main(int argc,char * argv[])
 	}
 	CHECK(rc == MDB_NOTFOUND, "mdb_cursor_get");
 	mdb_cursor_close(cursor);
-	mdb_close(env, dbi);
-
 	mdb_txn_abort(txn);
+
+	mdb_dbi_close(env, dbi);
 #endif
 	mdb_env_close(env);
 
diff --git a/external/db_drivers/liblmdb64/sample-mdb.txt b/external/db_drivers/liblmdb64/sample-mdb.txt
index d311f8e9..10a25687 100644
--- a/external/db_drivers/liblmdb64/sample-mdb.txt
+++ b/external/db_drivers/liblmdb64/sample-mdb.txt
@@ -32,7 +32,7 @@ int main(int argc,char * argv[])
 	rc = mdb_env_create(&env);
 	rc = mdb_env_open(env, "./testdb", 0, 0664);
 	rc = mdb_txn_begin(env, NULL, 0, &txn);
-	rc = mdb_open(txn, NULL, 0, &dbi);
+	rc = mdb_dbi_open(txn, NULL, 0, &dbi);
 
 	key.mv_size = sizeof(int);
 	key.mv_data = sval;
@@ -56,7 +56,7 @@ int main(int argc,char * argv[])
 	mdb_cursor_close(cursor);
 	mdb_txn_abort(txn);
 leave:
-	mdb_close(env, dbi);
+	mdb_dbi_close(env, dbi);
 	mdb_env_close(env);
 	return 0;
 }