MDEV-19371: Implement binlog_expire_logs_seconds for purging of binary logs

Part1: Functional changes

Backporting upstream changes.
commit a7e1ef858ee82493dd8ad9a76bc9c22fe3b8c05b
Author: Neha Kumari <neha.n.kumari@oracle.com>
Note:
From the upstream patch only the new option binlog_expire_logs_seconds
specific changes are taken.

* Unlike in the upstream patch 'binlog_expire_logs_seconds' does not
  replace the "old" 'expire_logs_days', to preserve backward-compatibility.

* Datatype of 'expire_logs_days' variable is changed to double.

* Default value of 'binlog_expire_logs_seconds=0' similar to
  'expire_logs_days'.

* The purge_time can be specified in days with the micro-day precision.
  Eg:
  expire_logs_days=1 is the same as expire_logs_days=1.000000 to make
    binlog_expire_logs_seconds=86400.
  binlog_expire_logs_seconds=1 is the same as expire_logs_days=0.000012.

* If binary log is disabled and option 'expire_logs_days' or
  'binlog_expire_logs_seconds' used with purge_time > 0 a warning will be
  issued.

sql/log.cc

@@ -7033,12 +7033,14 @@ void MYSQL_BIN_LOG::purge()
 {
   mysql_mutex_assert_not_owner(&LOCK_log);
 #ifdef HAVE_REPLICATION
-  if (expire_logs_days)
+  if (binlog_expire_logs_seconds)
   {
     DEBUG_SYNC(current_thd, "at_purge_logs_before_date");
-    time_t purge_time= my_time(0) - expire_logs_days*24*60*60;
+    time_t purge_time= my_time(0) - binlog_expire_logs_seconds;
+    DBUG_EXECUTE_IF("expire_logs_always", { purge_time = my_time(0); });
     if (purge_time >= 0)
     {
+      ha_flush_logs();
       purge_logs_before_date(purge_time);
     }
     DEBUG_SYNC(current_thd, "after_purge_logs_before_date");

sql/mysqld.cc

@@ -511,7 +511,9 @@ ulong current_pid;
 ulong slow_launch_threads = 0;
 uint sync_binlog_period= 0, sync_relaylog_period= 0,
      sync_relayloginfo_period= 0, sync_masterinfo_period= 0;
-ulong expire_logs_days = 0;
+double expire_logs_days = 0;
+ulong binlog_expire_logs_seconds = 0;
+
 /**
   Soft upper limit for number of sp_head objects that can be stored
   in the sp_cache for one connection.
@@ -725,6 +727,8 @@ char *opt_relay_logname = 0, *opt_relaylog_index_name=0;
 char *opt_logname, *opt_slow_logname, *opt_bin_logname;
 char *opt_binlog_index_name=0;
 
+
+
 /* Static variables */
 
 my_bool opt_stack_trace;
@@ -5283,11 +5287,20 @@ static int init_server_components()
   }
 
 #ifdef HAVE_REPLICATION
-  if (opt_bin_log && expire_logs_days)
+  if (opt_bin_log)
+  {
+    if (binlog_expire_logs_seconds)
+    {
+      time_t purge_time= server_start_time - binlog_expire_logs_seconds;
+      if (purge_time >= 0)
+        mysql_bin_log.purge_logs_before_date(purge_time);
+    }
+  }
+  else
   {
-    time_t purge_time= server_start_time - expire_logs_days*24*60*60;
-    if (purge_time >= 0)
-      mysql_bin_log.purge_logs_before_date(purge_time);
+    if (binlog_expire_logs_seconds)
+      sql_print_warning("You need to use --log-bin to make --expire-logs-days "
+                        "or --binlog-expire-logs-seconds work.");
   }
 #endif
 
@@ -7911,6 +7924,17 @@ mysqld_get_one_option(const struct my_option *opt, const char *argument,
     }
     break;
   }
+  case (int)OPT_EXPIRE_LOGS_DAYS:
+  {
+    binlog_expire_logs_seconds= (ulong)(expire_logs_days*24*60*60);
+    break;
+  }
+  case (int)OPT_BINLOG_EXPIRE_LOGS_SECONDS:
+  {
+    expire_logs_days= (binlog_expire_logs_seconds/double (24*60*60));
+    break;
+  }
+
 #ifdef HAVE_REPLICATION
   case (int)OPT_REPLICATE_IGNORE_DB:
   {

sql/mysqld.h

@@ -155,7 +155,8 @@ extern bool opt_endinfo, using_udf_functions;
 extern my_bool locked_in_memory;
 extern bool opt_using_transactions;
 extern ulong current_pid;
-extern ulong expire_logs_days;
+extern double expire_logs_days;
+extern ulong binlog_expire_logs_seconds;
 extern my_bool relay_log_recovery;
 extern uint sync_binlog_period, sync_relaylog_period, 
             sync_relayloginfo_period, sync_masterinfo_period;
@@ -777,6 +778,8 @@ enum options_mysqld
   OPT_BINLOG_IGNORE_DB,
   OPT_BIN_LOG,
   OPT_BOOTSTRAP,
+  OPT_EXPIRE_LOGS_DAYS,
+  OPT_BINLOG_EXPIRE_LOGS_SECONDS,
   OPT_CONSOLE,
   OPT_DEBUG_SYNC_TIMEOUT,
   OPT_REMOVED_OPTION,

sql/sys_vars.cc

@@ -1156,14 +1156,46 @@ static Sys_var_enum Sys_event_scheduler(
        ON_CHECK(event_scheduler_check), ON_UPDATE(event_scheduler_update));
 #endif
 
-static Sys_var_on_access_global<Sys_var_ulong,
+static bool copy_to_expire_logs_days(sys_var *, THD *,
+                                     enum_var_type type)
+{
+  expire_logs_days= binlog_expire_logs_seconds / (double)(24 * 60 * 60);
+  return false;
+}
+
+static bool copy_to_binlog_expire_logs_seconds(sys_var *, THD *,
+                                               enum_var_type type)
+{
+  binlog_expire_logs_seconds= (ulong)(expire_logs_days * 24 * 60 * 60);
+  return false;
+}
+
+static Sys_var_on_access_global<Sys_var_double,
                                 PRIV_SET_SYSTEM_GLOBAL_VAR_EXPIRE_LOGS_DAYS>
 Sys_expire_logs_days(
        "expire_logs_days",
        "If non-zero, binary logs will be purged after expire_logs_days "
-       "days; possible purges happen at startup and at binary log rotation",
+       "days; It and binlog_expire_logs_seconds are aliases, such that "
+       "changes in one are converted into the other, presentable as a "
+       "decimal value with 1/1000000 of the day precision; possible "
+       "purges happen at startup and at binary log rotation",
        GLOBAL_VAR(expire_logs_days),
-       CMD_LINE(REQUIRED_ARG), VALID_RANGE(0, 99), DEFAULT(0), BLOCK_SIZE(1));
+       CMD_LINE(REQUIRED_ARG, OPT_EXPIRE_LOGS_DAYS), VALID_RANGE(0, 99),
+       DEFAULT(0), NO_MUTEX_GUARD, NOT_IN_BINLOG, ON_CHECK(0),
+       ON_UPDATE(copy_to_binlog_expire_logs_seconds));
+
+static Sys_var_on_access_global<Sys_var_ulong,
+                                PRIV_SET_SYSTEM_GLOBAL_VAR_EXPIRE_LOGS_DAYS>
+Sys_binlog_expire_logs_seconds(
+       "binlog_expire_logs_seconds",
+       "If non-zero, binary logs will be purged after "
+       "binlog_expire_logs_seconds seconds; It and expire_logs_days are "
+       "aliases, such that changes in one are converted into the other. "
+       "Possible purges happen at startup and at binary log rotation.",
+       GLOBAL_VAR(binlog_expire_logs_seconds),
+       CMD_LINE(REQUIRED_ARG, OPT_BINLOG_EXPIRE_LOGS_SECONDS),
+       VALID_RANGE(0, 0xFFFFFFFF), DEFAULT(0), BLOCK_SIZE(1), NO_MUTEX_GUARD,
+       NOT_IN_BINLOG, ON_CHECK(0), ON_UPDATE(copy_to_expire_logs_days));
 
 static Sys_var_mybool Sys_flush(
        "flush", "Flush MyISAM tables to disk between SQL commands",