MDEV-4478: Implement GTID "strict mode"

When @@GLOBAL.gtid_strict_mode=1, then certain operations result
in error that would otherwise result in out-of-order binlog files
between servers.

GTID sequence numbers are now allocated independently per domain;
this results in less/no holes in GTID sequences, increasing the
likelyhood that diverging binlogs will be caught by the slave when
GTID strict mode is enabled.

1 files changed, 11 insertions, 2 deletions

diff --git a/sql/rpl_gtid.h b/sql/rpl_gtid.h
index cc3c99f40b7..fefce684c2c 100644
--- a/sql/rpl_gtid.h
+++ b/sql/rpl_gtid.h
@@ -131,6 +131,10 @@ struct rpl_binlog_state
     HASH hash;                /* Containing all server_id for one domain_id */
     /* The most recent entry in the hash. */
     rpl_gtid *last_gtid;
+    /* Counter to allocate next seq_no for this domain. */
+    uint64 seq_no_counter;
+
+    int update_element(const rpl_gtid *gtid);
   };
   /* Mapping from domain_id to collection of elements. */
   HASH hash;
@@ -144,8 +148,12 @@ struct rpl_binlog_state
   void reset();
   void free();
   bool load(struct rpl_gtid *list, uint32 count);
-  int update(const struct rpl_gtid *gtid);
-  uint64 seq_no_from_state();
+  int update(const struct rpl_gtid *gtid, bool strict);
+  int update_with_next_gtid(uint32 domain_id, uint32 server_id,
+                             rpl_gtid *gtid);
+  int alloc_element(const rpl_gtid *gtid);
+  bool check_strict_sequence(uint32 domain_id, uint32 server_id, uint64 seq_no);
+  int bump_seq_no_if_needed(uint32 domain_id, uint64 seq_no);
   int write_to_iocache(IO_CACHE *dest);
   int read_from_iocache(IO_CACHE *src);
   uint32 count();
@@ -153,6 +161,7 @@ struct rpl_binlog_state
   int get_most_recent_gtid_list(rpl_gtid **list, uint32 *size);
   bool append_pos(String *str);
   rpl_gtid *find(uint32 domain_id, uint32 server_id);
+  rpl_gtid *find_most_recent(uint32 domain_id);
 };