Merge remote-tracking branch 'origin/mdb.RE/0.9'

libraries/liblmdb/CHANGES

@@ -8,9 +8,17 @@ LMDB 0.9.17 Release Engineering
 	Fix ITS#8264 cursor_del cursor tracking
 	Fix ITS#8263 cursor_put cursor tracking
 	Fix ITS#7771 fakepage cursor tracking
+	Fix ITS#7789 ensure mapsize >= pages in use
+	Fix ITS#7971 mdb_txn_renew0() new reader slots
+	Fix ITS#7969 use __sync_synchronize on non-x86
+	Added mdb_txn_id() (ITS#7994)
+	Added robust mutex support
+	Miscellaneous cleanup/simplification
 	Build
 		Create install dirs if needed (ITS#8256)
 		Fix ThreadProc decl on Win32/MSVC (ITS#8270)
+		Added ssize_t typedef for MSVC (ITS#8067)
+		Use ANSI apis on Windows (ITS#8069)
 
 LMDB 0.9.16 Release (2015/08/14)
 	Fix cursor EOF bug (ITS#8190)

libraries/liblmdb/lmdb.h

@@ -49,9 +49,13 @@
  *	  stale locks can block further operation.
  *
  *	  Fix: Check for stale readers periodically, using the
- *	  #mdb_reader_check function or the \ref mdb_stat_1 "mdb_stat" tool. Or just
- *	  make all programs using the database close it; the lockfile
- *	  is always reset on first open of the environment.
+ *	  #mdb_reader_check function or the \ref mdb_stat_1 "mdb_stat" tool.
+ *	  Stale writers will be cleared automatically on some systems:
+ *	  - Windows - automatic
+ *	  - Linux, systems using POSIX mutexes with Robust option - automatic
+ *	  - not on BSD, systems using POSIX semaphores.
+ *	  Otherwise just make all programs using the database close it;
+ *	  the lockfile is always reset on first open of the environment.
  *
  *	- On BSD systems or others configured with MDB_USE_POSIX_SEM,
  *	  startup can fail due to semaphores owned by another userid.
@@ -106,6 +110,9 @@
  *	  for stale readers is performed or the lockfile is reset,
  *	  since the process may not remove it from the lockfile.
  *
+ *	  This does not apply to write transactions if the system clears
+ *	  stale writers, see above.
+ *
  *	- If you do that anyway, do a periodic check for stale readers. Or
  *	  close the environment once in a while, so the lockfile can get reset.
  *
@@ -391,7 +398,7 @@ typedef enum MDB_cursor_op {
 #define MDB_PAGE_NOTFOUND	(-30797)
 	/** Located page was wrong type */
 #define MDB_CORRUPTED	(-30796)
-	/** Update of meta page failed, probably I/O error */
+	/** Update of meta page failed or environment had fatal error */
 #define MDB_PANIC		(-30795)
 	/** Environment version mismatch */
 #define MDB_VERSION_MISMATCH	(-30794)
@@ -424,7 +431,7 @@ typedef enum MDB_cursor_op {
 #define MDB_INCOMPATIBLE	(-30784)
 	/** Invalid reuse of reader locktable slot */
 #define MDB_BAD_RSLOT		(-30783)
-	/** Transaction cannot recover - it must be aborted */
+	/** Transaction must abort, has a child, or is invalid */
 #define MDB_BAD_TXN			(-30782)
 	/** Unsupported size of key/DB name/data, or wrong DUPFIXED size */
 #define MDB_BAD_VALSIZE		(-30781)
@@ -953,6 +960,17 @@ int  mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **
 	 */
 MDB_env *mdb_txn_env(MDB_txn *txn);
 
+	/** @brief Return the transaction's ID.
+	 *
+	 * This returns the identifier associated with this transaction. For a
+	 * read-only transaction, this corresponds to the snapshot being read;
+	 * concurrent readers will frequently have the same transaction ID.
+	 *
+	 * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+	 * @return A transaction ID, valid if input is an active transaction.
+	 */
+size_t mdb_txn_id(MDB_txn *txn);
+
 	/** @brief Commit all the operations of a transaction into the database.
 	 *
 	 * The transaction handle is freed. It and its cursors must not be used