MDEV-7145: Delayed replication, cleanup some code

The original MySQL patch left some refactoring todo's, possibly
because of known conflicts with other parallel development (like
info-repository feature perhaps).

This patch fixes those todos/refactorings.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

sql/log.cc

@@ -4400,7 +4400,7 @@ int MYSQL_BIN_LOG::purge_first_log(Relay_log_info* rli, bool included)
   }
 
   /* Store where we are in the new file for the execution thread */
-  flush_relay_log_info(rli);
+  rli->flush();
 
   DBUG_EXECUTE_IF("crash_before_purge_logs", DBUG_SUICIDE(););
 

sql/log_event.cc

@@ -6402,7 +6402,7 @@ bool Rotate_log_event::write()
   The NOTES below is a wrong comment which will disappear when 4.1 is merged.
 
   This must only be called from the Slave SQL thread, since it calls
-  flush_relay_log_info().
+  Relay_log_info::flush().
 
   @retval
     0	ok
@@ -6457,7 +6457,7 @@ int Rotate_log_event::do_update_pos(rpl_group_info *rgi)
                         (ulong) rli->group_master_log_pos));
     mysql_mutex_unlock(&rli->data_lock);
     rpl_global_gtid_slave_state->record_and_update_gtid(thd, rgi);
-    flush_relay_log_info(rli);
+    rli->flush();
     
     /*
       Reset thd->variables.option_bits and sql_mode etc, because this could
@@ -8228,7 +8228,7 @@ void Stop_log_event::print(FILE* file, PRINT_EVENT_INFO* print_event_info)
   here, the master was sane.
 
   This must only be called from the Slave SQL thread, since it calls
-  flush_relay_log_info().
+  Relay_log_info::flush().
 */
 
 int Stop_log_event::do_update_pos(rpl_group_info *rgi)
@@ -8248,7 +8248,7 @@ int Stop_log_event::do_update_pos(rpl_group_info *rgi)
   {
     rpl_global_gtid_slave_state->record_and_update_gtid(thd, rgi);
     rli->inc_group_relay_log_pos(0, rgi);
-    flush_relay_log_info(rli);
+    rli->flush();
   }
   DBUG_RETURN(0);
 }

sql/rpl_mi.cc

@@ -647,7 +647,7 @@ file '%s')", fname);
                             (ulong) mi->master_log_pos));
 
   mi->rli.mi= mi;
-  if (init_relay_log_info(&mi->rli, slave_info_fname))
+  if (mi->rli.init(slave_info_fname))
     goto err;
 
   mi->inited = 1;

sql/rpl_rli.cc

@@ -110,19 +110,6 @@ Relay_log_info::~Relay_log_info()
 }
 
 
-/**
-  Wrapper around Relay_log_info::init(const char *).
-
-  @todo Remove this and replace all calls to it by calls to
-  Relay_log_info::init(const char *). /SVEN
-*/
-int init_relay_log_info(Relay_log_info* rli,
-			const char* info_fname)
-{
-  return rli->init(info_fname);
-}
-
-
 /**
   Read the relay_log.info file.
 
@@ -135,7 +122,7 @@ int Relay_log_info::init(const char* info_fname)
   char fname[FN_REFLEN+128];
   const char* msg = 0;
   int error = 0;
-  DBUG_ENTER("init_relay_log_info");
+  DBUG_ENTER("Relay_log_info::init");
 
   if (inited)                       // Set if this function called
     DBUG_RETURN(0);
@@ -242,7 +229,7 @@ a file name for --relay-log-index option", opt_relaylog_index_name);
                        max_relay_log_size, 1, TRUE))
     {
       mysql_mutex_unlock(&data_lock);
-      sql_print_error("Failed when trying to open logs for '%s' in init_relay_log_info(). Error: %M", ln, my_errno);
+      sql_print_error("Failed when trying to open logs for '%s' in Relay_log_info::init(). Error: %M", ln, my_errno);
       DBUG_RETURN(1);
     }
   }
@@ -409,10 +396,10 @@ Failed to open the existing relay log info file '%s' (errno %d)",
 
   /*
     Now change the cache from READ to WRITE - must do this
-    before flush_relay_log_info
+    before Relay_log_info::flush()
   */
   reinit_io_cache(&info_file, WRITE_CACHE,0L,0,1);
-  if ((error= flush_relay_log_info(this)))
+  if ((error= flush()))
   {
     msg= "Failed to flush relay log info file";
     goto err;
@@ -1108,10 +1095,10 @@ int purge_relay_logs(Relay_log_info* rli, THD *thd, bool just_reset,
     Indeed, rli->inited==0 does not imply that they already are empty.
     It could be that slave's info initialization partly succeeded :
     for example if relay-log.info existed but *relay-bin*.*
-    have been manually removed, init_relay_log_info reads the old
-    relay-log.info and fills rli->master_log_*, then init_relay_log_info
+    have been manually removed, Relay_log_info::init() reads the old
+    relay-log.info and fills rli->master_log_*, then Relay_log_info::init()
     checks for the existence of the relay log, this fails and
-    init_relay_log_info leaves rli->inited to 0.
+    Relay_log_info::init() leaves rli->inited to 0.
     In that pathological case, rli->master_log_pos* will be properly reinited
     at the next START SLAVE (as RESET SLAVE or CHANGE
     MASTER, the callers of purge_relay_logs, will delete bogus *.info files
@@ -1349,7 +1336,7 @@ void Relay_log_info::stmt_done(my_off_t event_master_log_pos, THD *thd,
     }
     DBUG_EXECUTE_IF("inject_crash_before_flush_rli", DBUG_SUICIDE(););
     if (mi->using_gtid == Master_info::USE_GTID_NO)
-      flush_relay_log_info(this);
+      flush();
     DBUG_EXECUTE_IF("inject_crash_after_flush_rli", DBUG_SUICIDE(););
   }
   DBUG_VOID_RETURN;
@@ -2010,4 +1997,79 @@ bool rpl_sql_thread_info::cached_charset_compare(char *charset) const
   DBUG_RETURN(0);
 }
 
+
+/**
+  Store the file and position where the slave's SQL thread are in the
+  relay log.
+
+  Notes:
+
+  - This function should be called either from the slave SQL thread,
+    or when the slave thread is not running.  (It reads the
+    group_{relay|master}_log_{pos|name} and delay fields in the rli
+    object.  These may only be modified by the slave SQL thread or by
+    a client thread when the slave SQL thread is not running.)
+
+  - If there is an active transaction, then we do not update the
+    position in the relay log.  This is to ensure that we re-execute
+    statements if we die in the middle of an transaction that was
+    rolled back.
+
+  - As a transaction never spans binary logs, we don't have to handle
+    the case where we do a relay-log-rotation in the middle of the
+    transaction.  If transactions could span several binlogs, we would
+    have to ensure that we do not delete the relay log file where the
+    transaction started before switching to a new relay log file.
+
+  - Error can happen if writing to file fails or if flushing the file
+    fails.
+
+  @param rli The object representing the Relay_log_info.
+
+  @todo Change the log file information to a binary format to avoid
+  calling longlong2str.
+
+  @return 0 on success, 1 on error.
+*/
+bool Relay_log_info::flush()
+{
+  bool error=0;
+
+  DBUG_ENTER("Relay_log_info::flush()");
+
+  IO_CACHE *file = &info_file;
+  // 2*file name, 2*long long, 2*unsigned long, 6*'\n'
+  char buff[FN_REFLEN * 2 + 22 * 2 + 10 * 2 + 6], *pos;
+  my_b_seek(file, 0L);
+  pos= longlong10_to_str(LINES_IN_RELAY_LOG_INFO_WITH_DELAY, buff, 10);
+  *pos++='\n';
+  pos=strmov(pos, group_relay_log_name);
+  *pos++='\n';
+  pos=longlong10_to_str(group_relay_log_pos, pos, 10);
+  *pos++='\n';
+  pos=strmov(pos, group_master_log_name);
+  *pos++='\n';
+  pos=longlong10_to_str(group_master_log_pos, pos, 10);
+  *pos++='\n';
+  pos= longlong10_to_str(sql_delay, pos, 10);
+  *pos++= '\n';
+  if (my_b_write(file, (uchar*) buff, (size_t) (pos-buff)))
+    error=1;
+  if (flush_io_cache(file))
+    error=1;
+  if (sync_relayloginfo_period &&
+      !error &&
+      ++sync_counter >= sync_relayloginfo_period)
+  {
+    if (my_sync(info_fd, MYF(MY_WME)))
+      error=1;
+    sync_counter= 0;
+  }
+  /* 
+    Flushing the relay log is done by the slave I/O thread 
+    or by the user on STOP SLAVE. 
+   */
+  DBUG_RETURN(error);
+}
+
 #endif

sql/rpl_rli.h

@@ -42,7 +42,7 @@ class Rpl_filter;
 
   Relay_log_info is initialized from the slave.info file if such
   exists.  Otherwise, data members are intialized with defaults. The
-  initialization is done with init_relay_log_info() call.
+  initialization is done with Relay_log_info::init() call.
 
   The format of slave.info file:
 
@@ -536,7 +536,7 @@ class Relay_log_info : public Slave_reporting_capability
     MASTER_DELAY=X.  Read by SQL thread and by client threads
     executing SHOW SLAVE STATUS.  Note: must not be written while the
     slave SQL thread is running, since the SQL thread reads it without
-    a lock when executing flush_relay_log_info().
+    a lock when executing Relay_log_info::flush().
   */
   int sql_delay;
 
@@ -954,17 +954,6 @@ class rpl_sql_thread_info
 };
 
 
-/**
-  Reads the relay_log.info file.
-
-  @todo This is a wrapper around Relay_log_info::init(). It's only
-  kept for historical reasons. It would be good if we removed this
-  function and replaced all calls to it by calls to
-  Relay_log_info::init(). /SVEN
-*/
-int init_relay_log_info(Relay_log_info* rli, const char* info_fname);
-
-
 extern struct rpl_slave_state *rpl_global_gtid_slave_state;
 extern gtid_waiting rpl_global_gtid_waiting;
 

sql/slave.cc

@@ -738,7 +738,7 @@ int terminate_slave_threads(Master_info* mi,int thread_mask,bool skip_lock)
     DBUG_PRINT("info",("Flushing relay-log info file."));
     if (current_thd)
       THD_STAGE_INFO(current_thd, stage_flushing_relay_log_info_file);
-    if (flush_relay_log_info(&mi->rli))
+    if (mi->rli.flush())
       DBUG_RETURN(ER_ERROR_DURING_FLUSH_LOGS);
     
     if (my_sync(mi->rli.info_fd, MYF(MY_WME)))
@@ -5124,7 +5124,7 @@ pthread_handler_t handle_slave_sql(void *arg)
   {
     ulong domain_count;
 
-    flush_relay_log_info(rli);
+    rli->flush();
     if (mi->using_parallel())
     {
       /*
@@ -6708,88 +6708,6 @@ MYSQL *rpl_connect_master(MYSQL *mysql)
 }
 #endif
 
-/**
-  Store the file and position where the slave's SQL thread are in the
-  relay log.
-
-  Notes:
-
-  - This function should be called either from the slave SQL thread,
-    or when the slave thread is not running.  (It reads the
-    group_{relay|master}_log_{pos|name} and delay fields in the rli
-    object.  These may only be modified by the slave SQL thread or by
-    a client thread when the slave SQL thread is not running.)
-
-  - If there is an active transaction, then we do not update the
-    position in the relay log.  This is to ensure that we re-execute
-    statements if we die in the middle of an transaction that was
-    rolled back.
-
-  - As a transaction never spans binary logs, we don't have to handle
-    the case where we do a relay-log-rotation in the middle of the
-    transaction.  If transactions could span several binlogs, we would
-    have to ensure that we do not delete the relay log file where the
-    transaction started before switching to a new relay log file.
-
-  - Error can happen if writing to file fails or if flushing the file
-    fails.
-
-  @param rli The object representing the Relay_log_info.
-
-  @todo Change the log file information to a binary format to avoid
-  calling longlong2str.
-
-  @todo Move the member function into rpl_rli.cc and get rid of the
-  global function. /SVEN
-
-  @return 0 on success, 1 on error.
-*/
-bool flush_relay_log_info(Relay_log_info* rli)
-{
-  return rli->flush();
-}
-
-bool Relay_log_info::flush()
-{
-  bool error=0;
-
-  DBUG_ENTER("Relay_log_info::flush()");
-
-  IO_CACHE *file = &info_file;
-  // 2*file name, 2*long long, 2*unsigned long, 6*'\n'
-  char buff[FN_REFLEN * 2 + 22 * 2 + 10 * 2 + 6], *pos;
-  my_b_seek(file, 0L);
-  pos= longlong10_to_str(LINES_IN_RELAY_LOG_INFO_WITH_DELAY, buff, 10);
-  *pos++='\n';
-  pos=strmov(pos, group_relay_log_name);
-  *pos++='\n';
-  pos=longlong10_to_str(group_relay_log_pos, pos, 10);
-  *pos++='\n';
-  pos=strmov(pos, group_master_log_name);
-  *pos++='\n';
-  pos=longlong10_to_str(group_master_log_pos, pos, 10);
-  *pos++='\n';
-  pos= longlong10_to_str(sql_delay, pos, 10);
-  *pos++= '\n';
-  if (my_b_write(file, (uchar*) buff, (size_t) (pos-buff)))
-    error=1;
-  if (flush_io_cache(file))
-    error=1;
-  if (sync_relayloginfo_period &&
-      !error &&
-      ++sync_counter >= sync_relayloginfo_period)
-  {
-    if (my_sync(info_fd, MYF(MY_WME)))
-      error=1;
-    sync_counter= 0;
-  }
-  /* 
-    Flushing the relay log is done by the slave I/O thread 
-    or by the user on STOP SLAVE. 
-   */
-  DBUG_RETURN(error);
-}
-
 
 /*
   Called when we notice that the current "hot" log got rotated under our feet.
@@ -7146,7 +7064,7 @@ static Log_event* next_event(rpl_group_info *rgi, ulonglong *event_size)
         }
         rli->event_relay_log_pos = BIN_LOG_HEADER_SIZE;
         strmake_buf(rli->event_relay_log_name,rli->linfo.log_file_name);
-        flush_relay_log_info(rli);
+        rli->flush();
       }
 
       /*

sql/slave.h

@@ -183,7 +183,6 @@ extern const char *relay_log_basename;
 int init_slave();
 int init_recovery(Master_info* mi, const char** errmsg);
 void init_slave_skip_errors(const char* arg);
-bool flush_relay_log_info(Relay_log_info* rli);
 int register_slave_on_master(MYSQL* mysql);
 int terminate_slave_threads(Master_info* mi, int thread_mask,
 			     bool skip_lock = 0);

sql/sql_binlog.cc

@@ -100,7 +100,7 @@ static int check_event_type(int type, Relay_log_info *rli)
     /*
       It is not meaningful to execute other events than row-events and
       FD events. It would even be dangerous to execute Stop_log_event
-      and Rotate_log_event since they call flush_relay_log_info, which
+      and Rotate_log_event since they call Relay_log_info::flush(), which
       is not allowed to call by other threads than the slave SQL
       thread when the slave SQL thread is running.
     */

sql/sql_repl.cc

@@ -494,7 +494,7 @@ static enum enum_binlog_checksum_alg get_binlog_checksum_value_at_connect(THD *
 
   TODO
     - Inform the slave threads that they should sync the position
-      in the binary log file with flush_relay_log_info.
+      in the binary log file with Relay_log_info::flush().
       Now they sync is done for next read.
 */
 
@@ -3818,7 +3818,7 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
     in-memory value at restart (thus causing errors, as the old relay log does
     not exist anymore).
   */
-  flush_relay_log_info(&mi->rli);
+  mi->rli.flush();
   mysql_cond_broadcast(&mi->data_cond);
   mysql_mutex_unlock(&mi->rli.data_lock);