mdbx: Merge branch 'devel'.

CHANGES

@@ -1,7 +1,9 @@
 LMDB 0.9 Change Log
 
 LMDB 0.9.18 Release Engineering
+	Add MDB_PREV_MULTIPLE
 	already done for mdbx - Fix robust mutex detection on glibc 2.10-11 (ITS#8330)
+	Fix page_search_root assert on FreeDB (ITS#8336)
 	n/a for mdbx - Check for utf8_to_utf16 failures (ITS#7992)
 	Catch strdup failure in mdb_dbi_open
 	Build

lmdb.h

@@ -76,6 +76,11 @@
  *	  access to locks and lock file. Exceptions: On read-only filesystems
  *	  or with the #MDB_NOLOCK flag described under #mdb_env_open().
  *
+ *	- An LMDB configuration will often reserve considerable \b unused
+ *	  memory address space and maybe file size for future growth.
+ *	  This does not use actual memory or disk space, but users may need
+ *	  to understand the difference so they won't be scared off.
+ *
  *	- By default, in versions before 0.9.10, unused portions of the data
  *	  file might receive garbage data from memory freed by other code.
  *	  (This does not happen when using the #MDB_WRITEMAP flag.) As of
@@ -387,7 +392,9 @@ typedef enum MDB_cursor_op {
 	MDB_PREV_NODUP,			/**< Position at last data item of previous key */
 	MDB_SET,				/**< Position at specified key */
 	MDB_SET_KEY,			/**< Position at specified key, return key + data */
-	MDB_SET_RANGE			/**< Position at first key greater than or equal to specified key. */
+	MDB_SET_RANGE,			/**< Position at first key greater than or equal to specified key. */
+	MDB_PREV_MULTIPLE		/**< Position at previous page and return key and up to
+								a page of duplicate data items. Only for #MDB_DUPFIXED */
 } MDB_cursor_op;
 
 /** @defgroup  errors	Return Codes

mdb.c

@@ -4097,6 +4097,7 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
 	size_t prev_mapsize = head->mm_mapsize;
 	MDB_meta* tail = META_IS_WEAK(head) ? head : mdb_env_meta_flipflop(env, head);
 	off_t offset = (char*) tail - env->me_map;
+	size_t used_size = env->me_psize * (pending->mm_last_pg + 1);
 
 	mdb_assert(env, (env->me_flags & (MDB_RDONLY | MDB_FATAL_ERROR)) == 0);
 	mdb_assert(env, META_IS_WEAK(head) || env->me_sync_pending != 0
@@ -4108,6 +4109,7 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
 	mdb_assert(env, pending->mm_txnid > stay->mm_txnid);
 
 	pending->mm_mapsize = env->me_mapsize;
+	mdb_assert(env, pending->mm_mapsize >= used_size);
 	if (unlikely(pending->mm_mapsize != prev_mapsize)) {
 		if (pending->mm_mapsize < prev_mapsize) {
 			/* LY: currently this can't happen, but force full-sync. */
@@ -4124,7 +4126,7 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
 	if (env->me_sync_pending && (flags & MDB_NOSYNC) == 0) {
 		if (env->me_flags & MDB_WRITEMAP) {
 			int mode = (flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
-			if (unlikely(msync(env->me_map, pending->mm_mapsize, mode))) {
+			if (unlikely(msync(env->me_map, used_size, mode))) {
 				rc = errno;
 				goto fail;
 			}
@@ -4729,13 +4731,23 @@ mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
 		return errno;
 	env->me_txns = m;
 
-	if (madvise(env->me_txns, rsize, MADV_DONTFORK | MADV_WILLNEED))
-		return errno;
+#ifdef MADV_NOHUGEPAGE
+	(void) madvise(env->me_txns, rsize, MADV_NOHUGEPAGE);
+#endif
 
 #ifdef MADV_DODUMP
-	madvise(env->me_txns, rsize, MADV_DODUMP);
+	(void) madvise(env->me_txns, rsize, MADV_DODUMP);
 #endif
 
+	if (madvise(env->me_txns, rsize, MADV_DONTFORK) < 0)
+		return errno;
+
+	if (madvise(env->me_txns, rsize, MADV_WILLNEED) < 0)
+		return errno;
+
+	if (madvise(env->me_txns, rsize, MADV_RANDOM) < 0)
+		return errno;
+
 	if (*excl > 0) {
 		pthread_mutexattr_t mattr;
 
@@ -6327,6 +6339,28 @@ fetchm:
 			}
 		}
 		break;
+	case MDB_PREV_MULTIPLE:
+		if (data == NULL) {
+			rc = EINVAL;
+			break;
+		}
+		if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
+			rc = MDB_INCOMPATIBLE;
+			break;
+		}
+		if (!(mc->mc_flags & C_INITIALIZED))
+			rc = mdb_cursor_first(mc, key, data);
+		else {
+			MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;
+			if (mx->mc_flags & C_INITIALIZED) {
+				rc = mdb_cursor_sibling(mx, 0);
+				if (rc == MDB_SUCCESS)
+					goto fetchm;
+			} else {
+				rc = MDB_NOTFOUND;
+			}
+		}
+		break;
 	case MDB_NEXT:
 	case MDB_NEXT_DUP:
 	case MDB_NEXT_NODUP:

tooltag

@@ -19,4 +19,9 @@
 	<title>mdb_stat - environment status tool</title>
 	<filename>mdb_stat.1</filename>
   </compound>
+  <compound kind="page">
+    <name>mdb_chk_1</name>
+	<title>mdb_chk - environment check tool</title>
+	<filename>mdb_chk.1</filename>
+  </compound>
 </tagfile>