MDEV-7145: Delayed replication, intermediate commit.

Initial merge of delayed replication from MySQL git.

The code from the initial push into MySQL is merged, and the
associated test case passes. A number of tasks are still pending:

1. Check full test suite run for any regressions or .result file updates.

2. Extend the feature to also work for parallel replication.

3. There are some todo-comments about future refactoring left from
MySQL, these should be located and merged on top.

4. There are some later related MySQL commits, these should be checked
and merged. These include:
    e134b9362ba0b750d6ac1b444780019622d14aa5
    b38f0f7857c073edfcc0a64675b7f7ede04be00f
    fd2b210383358fe7697f201e19ac9779879ba72a
    afc397376ec50e96b2918ee64e48baf4dda0d37d

5. The testcase from MySQL relies heavily on sleep and timing for
testing, and seems likely to sporadically fail on heavily loaded test
servers in buildbot or distro build farms.

Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/sql/slave.h b/sql/slave.h
index a78ae4cff6f..d28048af8ea 100644
--- a/sql/slave.h
+++ b/sql/slave.h
@@ -18,6 +18,14 @@
 #define SLAVE_H
 
 /**
+  MASTER_DELAY can be at most (1 << 31) - 1.
+*/
+#define MASTER_DELAY_MAX (0x7FFFFFFF)
+#if INT_MAX < 0x7FFFFFFF
+#error "don't support platforms where INT_MAX < 0x7FFFFFFF"
+#endif
+
+/**
   @defgroup Replication Replication
   @{
 
@@ -102,12 +110,14 @@ int init_dynarray_intvar_from_file(DYNAMIC_ARRAY* arr, IO_CACHE* f);
 
   In Master_info: run_lock, data_lock
   run_lock protects all information about the run state: slave_running, thd
-  and the existence of the I/O thread to stop/start it, you need this mutex).
+  and the existence of the I/O thread (to stop/start it, you need this mutex).
   data_lock protects some moving members of the struct: counters (log name,
   position) and relay log (MYSQL_BIN_LOG object).
 
   In Relay_log_info: run_lock, data_lock
   see Master_info
+  However, note that run_lock does not protect
+  Relay_log_info.run_state; that is protected by data_lock.
   
   Order of acquisition: if you want to have LOCK_active_mi and a run_lock, you
   must acquire LOCK_active_mi first.
@@ -247,6 +257,12 @@ int apply_event_and_update_pos(Log_event* ev, THD* thd,
 int apply_event_and_update_pos_for_parallel(Log_event* ev, THD* thd,
                                             struct rpl_group_info *rgi);
 
+int init_intvar_from_file(int* var, IO_CACHE* f, int default_val);
+int init_floatvar_from_file(float* var, IO_CACHE* f, float default_val);
+int init_strvar_from_file(char *var, int max_size, IO_CACHE *f,
+                          const char *default_val);
+int init_dynarray_intvar_from_file(DYNAMIC_ARRAY* arr, IO_CACHE* f);
+
 pthread_handler_t handle_slave_io(void *arg);
 void slave_output_error_info(rpl_group_info *rgi, THD *thd);
 pthread_handler_t handle_slave_sql(void *arg);