MDEV-6676: Optimistic parallel replication

Implement a new mode for parallel replication. In this mode, all transactions
are optimistically attempted applied in parallel. In case of conflicts, the
offending transaction is rolled back and retried later non-parallel.

This is an early-release patch to facilitate testing, more changes to user
interface / options will be expected. The new mode is not enabled by default.

1 files changed, 32 insertions, 0 deletions

diff --git a/sql/rpl_mi.h b/sql/rpl_mi.h
index 5eacbc97a95..6c970de608b 100644
--- a/sql/rpl_mi.h
+++ b/sql/rpl_mi.h
@@ -16,6 +16,18 @@
 #ifndef RPL_MI_H
 #define RPL_MI_H
 
+
+/*
+  Bit masks for the values in --slave-parallel-mode.
+  Note that these values cannot be changed - they are stored in master.info,
+  so need to be possible to read back in a different version of the server.
+*/
+#define SLAVE_PARALLEL_DOMAIN               (1ULL << 0)
+#define SLAVE_PARALLEL_FOLLOW_MASTER_COMMIT (1ULL << 1)
+#define SLAVE_PARALLEL_TRX                  (1ULL << 2)
+#define SLAVE_PARALLEL_WAITING              (1ULL << 3)
+
+
 #ifdef HAVE_REPLICATION
 
 #include "rpl_rli.h"
@@ -131,6 +143,8 @@ public:
 };
 
 
+extern TYPELIB slave_parallel_mode_typelib;
+
 /*****************************************************************************
   Replication IO Thread
 
@@ -180,6 +194,10 @@ class Master_info : public Slave_reporting_capability
     return connection_name.str == 0;
   }
   static const char *using_gtid_astext(enum enum_using_gtid arg);
+  bool using_parallel()
+  {
+    return opt_slave_parallel_threads > 0 && parallel_mode != 0;
+  }
 
   /* the variables below are needed because we can change masters on the fly */
   char master_log_name[FN_REFLEN+6]; /* Room for multi-*/
@@ -293,6 +311,13 @@ class Master_info : public Slave_reporting_capability
 
   /* domain-id based filter */
   Domain_id_filter domain_id_filter;
+
+  /*
+    The parallel replication modes, if any. A combination (binary OR) of any
+    of SLAVE_PARALLEL_DOMAIN, SLAVE_PARALLEL_FOLLOW_MASTER_COMMIT,
+    SLAVE_PARALLEL_TRX, and SLAVE_PARALLEL_WAITING.
+  */
+  ulonglong parallel_mode;
 };
 
 int init_master_info(Master_info* mi, const char* master_info_fname,
@@ -358,6 +383,13 @@ void create_logfile_name_with_suffix(char *res_file_name, size_t length,
 uchar *get_key_master_info(Master_info *mi, size_t *length,
                            my_bool not_used __attribute__((unused)));
 void free_key_master_info(Master_info *mi);
+int mi_cmdline_init();
+void mi_cmdline_destroy();
+void mi_slave_parallel_mode_lookup(LEX_STRING *connection_name,
+                                   ulonglong *out_mode);
+int mi_slave_parallel_mode_ptr(LEX_STRING *connection_name,
+                               ulonglong **out_mode_ptr,
+                               bool create_if_missing);
 
 
 #endif /* HAVE_REPLICATION */