Merge from 10.0-base to 10.0 the feature MDEV-4506: Parallel replication.

The merge is still missing a few hunks related to temporary tables and
InnoDB log file size. The associated code did not seem to exist in
10.0, so the merge of that needs more work. Until this is fixed, there
are a number of test failures as a result.

1 files changed, 35 insertions, 0 deletions

diff --git a/include/mysql/plugin.h b/include/mysql/plugin.h
index 2d3c0166ccf..bbfd93eb94a 100644
--- a/include/mysql/plugin.h
+++ b/include/mysql/plugin.h
@@ -699,6 +699,41 @@ void *thd_get_ha_data(const MYSQL_THD thd, const struct handlerton *hton);
 */
 void thd_set_ha_data(MYSQL_THD thd, const struct handlerton *hton,
                      const void *ha_data);
+
+
+/**
+  Signal that the first part of handler commit is finished, and that the
+  committed transaction is now visible and has fixed commit ordering with
+  respect to other transactions. The commit need _not_ be durable yet, and
+  typically will not be when this call makes sense.
+
+  This call is optional, if the storage engine does not call it the upper
+  layer will after the handler commit() method is done. However, the storage
+  engine may choose to call it itself to increase the possibility for group
+  commit.
+
+  In-order parallel replication uses this to apply different transaction in
+  parallel, but delay the commits of later transactions until earlier
+  transactions have committed first, thus achieving increased performance on
+  multi-core systems while still preserving full transaction consistency.
+
+  The storage engine can call this from within the commit() method, typically
+  after the commit record has been written to the transaction log, but before
+  the log has been fsync()'ed. This will allow the next replicated transaction
+  to proceed to commit before the first one has done fsync() or similar. Thus,
+  it becomes possible for multiple sequential replicated transactions to share
+  a single fsync() inside the engine in group commit.
+
+  Note that this method should _not_ be called from within the commit_ordered()
+  method, or any other place in the storage engine. When commit_ordered() is
+  used (typically when binlog is enabled), the transaction coordinator takes
+  care of this and makes group commit in the storage engine possible without
+  any other action needed on the part of the storage engine. This function
+  thd_wakeup_subsequent_commits() is only needed when no transaction
+  coordinator is used, meaning a single storage engine and no binary log.
+*/
+void thd_wakeup_subsequent_commits(MYSQL_THD thd, int wakeup_error);
+
 #ifdef __cplusplus
 }
 #endif