diff --git a/mysql-test/main/alter_table_online_debug.result b/mysql-test/main/alter_table_online_debug.result
index 021267a15f59c..3a615372ed54c 100644
--- a/mysql-test/main/alter_table_online_debug.result
+++ b/mysql-test/main/alter_table_online_debug.result
@@ -409,23 +409,23 @@ set debug_sync= 'now SIGNAL start_replication';
 set debug_sync= 'now WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
-3	51.220
+3	53.390
 set debug_sync= 'now SIGNAL proceed WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
-3	61.789
+3	63.559
 set debug_sync= 'now SIGNAL proceed WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
-3	70.325
+3	71.610
 set debug_sync= 'now SIGNAL proceed WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
-3	80.894
+3	81.780
 set debug_sync= 'now SIGNAL proceed WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
-3	89.431
+3	89.831
 set debug_sync= 'now SIGNAL proceed WAIT_FOR applied';
 select stage, progress from INFORMATION_SCHEMA.PROCESSLIST where id = @con;
 stage	progress
@@ -1157,7 +1157,7 @@ a	b
 30	30
 drop table t;
 set debug_sync= reset;
-set debug_dbug= @old_debug;
+set debug_dbug= @old_dbug;
 connection default;
 #
 # MDEV-30902 Server crash in LEX::first_lists_tables_same
@@ -1362,9 +1362,57 @@ b
 556
 drop table t;
 set debug_sync= reset;
+NOT FOUND /Slave SQL/ in mysqld.1.err
+#
+# MDEV-31646 Online alter applies binlog cache limit to cache writes
+#
+create table t (pk int primary key, a varchar(100)) engine=MyISAM;
+insert into t select seq, repeat('x', 100) from seq_1_to_500;
+set @cache.size= @@max_binlog_cache_size;
+set global max_binlog_cache_size= 4096;
+set debug_sync= 'now wait_for do_updates';
+connection con1;
+set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
+alter table t add b int, algorithm=copy, lock=none;
+connection default;
+update t set a = repeat('y', 100);
+show warnings;
+Level	Code	Message
+set debug_sync= 'now signal go';
+connection con1;
+show warnings;
+Level	Code	Message
+connection default;
+drop table t;
+set debug_sync= reset;
+set global max_binlog_cache_size= @cache.size;
+# Now make sure that smaller limits will be processed fine
+set @old_dbug=@@debug_dbug;
+create table t (pk int primary key, a text) engine=MyISAM;
+insert into t select seq, repeat('x', 1000) from seq_1_to_50;
+connection con1;
+set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
+alter table t add b int, algorithm=copy, lock=none;
+connection default;
+set debug_sync= 'now wait_for do_updates';
+set debug_dbug="+d,online_alter_small_cache";
+update t set a = repeat('y', 1000);
+ERROR HY000: Multi-row statements required more than 'max_binlog_stmt_cache_size' bytes of storage.
+show warnings;
+Level	Code	Message
+Error	1705	Multi-row statements required more than 'max_binlog_stmt_cache_size' bytes of storage.
+Error	1534	Writing one row to the row-based binary log failed
+Warning	1196	Some non-transactional changed tables couldn't be rolled back
+set debug_sync= 'now signal go';
+connection con1;
+show warnings;
+Level	Code	Message
+connection default;
+drop table t;
+set debug_sync= reset;
+set debug_dbug= @old_dbug;
 disconnect con1;
 disconnect con2;
-NOT FOUND /Slave SQL/ in mysqld.1.err
 #
 # End of 11.2 tests
 #
diff --git a/mysql-test/main/alter_table_online_debug.test b/mysql-test/main/alter_table_online_debug.test
index f6117acc1b763..c01964e30f561 100644
--- a/mysql-test/main/alter_table_online_debug.test
+++ b/mysql-test/main/alter_table_online_debug.test
@@ -2,6 +2,7 @@
 --source include/not_embedded.inc
 --source include/binlog_combinations.inc
 --source include/have_innodb.inc
+--source include/have_sequence.inc
 --source include/have_partition.inc
 set default_storage_engine= innodb;
 
@@ -1331,7 +1332,7 @@ select a, b from t;
 # Cleanup
 drop table t;
 set debug_sync= reset;
-set debug_dbug= @old_debug;
+set debug_dbug= @old_dbug;
 --connection default
 
 --echo #
@@ -1551,11 +1552,73 @@ drop table t;
 
 
 set debug_sync= reset;
---disconnect con1
---disconnect con2
 let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
 let SEARCH_PATTERN= Slave SQL;
 --source include/search_pattern_in_file.inc
+
+
+--echo #
+--echo # MDEV-31646 Online alter applies binlog cache limit to cache writes
+--echo #
+create table t (pk int primary key, a varchar(100)) engine=MyISAM;
+insert into t select seq, repeat('x', 100) from seq_1_to_500;
+
+set @cache.size= @@max_binlog_cache_size;
+set global max_binlog_cache_size= 4096;
+
+send set debug_sync= 'now wait_for do_updates';
+
+--connection con1
+set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
+send alter table t add b int, algorithm=copy, lock=none;
+
+--connection default
+--reap
+update t set a = repeat('y', 100);
+show warnings;
+
+set debug_sync= 'now signal go';
+
+--connection con1
+--reap
+show warnings;
+
+--connection default
+drop table t;
+set debug_sync= reset;
+set global max_binlog_cache_size= @cache.size;
+
+--echo # Now make sure that smaller limits will be processed fine
+
+set @old_dbug=@@debug_dbug;
+create table t (pk int primary key, a text) engine=MyISAM;
+insert into t select seq, repeat('x', 1000) from seq_1_to_50;
+
+--connection con1
+set debug_sync= 'alter_table_online_progress signal do_updates wait_for go';
+--send
+alter table t add b int, algorithm=copy, lock=none;
+
+--connection default
+set debug_sync= 'now wait_for do_updates';
+set debug_dbug="+d,online_alter_small_cache";
+--error ER_STMT_CACHE_FULL
+update t set a = repeat('y', 1000);
+show warnings;
+
+set debug_sync= 'now signal go';
+
+--connection con1
+--reap
+show warnings;
+
+--connection default
+drop table t;
+set debug_sync= reset;
+set debug_dbug= @old_dbug;
+
+--disconnect con1
+--disconnect con2
 --echo #
 --echo # End of 11.2 tests
 --echo #
diff --git a/sql/log.cc b/sql/log.cc
index d9e817004632d..8c57487d57edc 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -2286,13 +2286,21 @@ int binlog_log_row_online_alter(TABLE* table, const uchar *before_record,
   MY_BITMAP *old_rpl_write_set= table->rpl_write_set;
   table->rpl_write_set= &table->s->all_set;
 
+  table->online_alter_cache->store_prev_position();
   int error= (*log_func)(thd, table, table->s->online_alter_binlog,
-                         table->online_alter_cache, true,
+                         table->online_alter_cache,
+                         table->file->has_transactions_and_rollback(),
                          before_record, after_record);
 
   table->rpl_write_set= old_rpl_write_set;
 
-  return unlikely(error) ? HA_ERR_RBR_LOGGING_FAILED : 0;
+  if (unlikely(error))
+  {
+    table->online_alter_cache->restore_prev_position();
+    return HA_ERR_RBR_LOGGING_FAILED;
+  }
+
+  return 0;
 }
 
 static void
@@ -3843,9 +3851,8 @@ bool Event_log::open(enum cache_type io_cache_type_arg)
   if (error)
     return error;
 
-  longlong bytes_written= write_description_event(
-                              (enum_binlog_checksum_alg)binlog_checksum_options,
-                              encrypt_binlog, true, false);
+  longlong bytes_written= write_description_event(BINLOG_CHECKSUM_ALG_OFF,
+                                                  false, true, false);
   return bytes_written < 0;
 }
 
@@ -6419,8 +6426,11 @@ bool MYSQL_BIN_LOG::write_table_map(THD *thd, TABLE *table, bool with_annotate)
 
 
 #ifdef HAVE_REPLICATION
-static online_alter_cache_data *binlog_setup_cache_data(MEM_ROOT *root, TABLE_SHARE *share)
+static online_alter_cache_data *
+online_alter_binlog_setup_cache_data(MEM_ROOT *root, TABLE_SHARE *share)
 {
+  static ulong online_alter_cache_use= 0, online_alter_cache_disk_use= 0;
+
   auto cache= new (root) online_alter_cache_data();
   if (!cache || open_cached_file(&cache->cache_log, mysql_tmpdir,
                          LOG_PREFIX, (size_t)binlog_cache_size, MYF(MY_WME)))
@@ -6432,8 +6442,13 @@ static online_alter_cache_data *binlog_setup_cache_data(MEM_ROOT *root, TABLE_SH
   share->online_alter_binlog->acquire();
   cache->hton= share->db_type();
   cache->sink_log= share->online_alter_binlog;
-  cache->set_binlog_cache_info(max_binlog_cache_size, &binlog_cache_use,
-                               &binlog_cache_disk_use);
+
+  my_off_t binlog_max_size= SIZE_T_MAX; // maximum possible cache size
+  DBUG_EXECUTE_IF("online_alter_small_cache", binlog_max_size= 4096;);
+
+  cache->set_binlog_cache_info(binlog_max_size,
+                               &online_alter_cache_use,
+                               &online_alter_cache_disk_use);
   cache->store_prev_position();
   return cache;
 }
@@ -6451,7 +6466,7 @@ online_alter_cache_data *online_alter_binlog_get_cache_data(THD *thd, TABLE *tab
   }
 
   MEM_ROOT *root= &thd->transaction->mem_root;
-  auto *new_cache_data= binlog_setup_cache_data(root, table->s);
+  auto *new_cache_data= online_alter_binlog_setup_cache_data(root, table->s);
   list.push_back(*new_cache_data);
 
   return new_cache_data;
@@ -7748,7 +7763,7 @@ static int binlog_online_alter_end_trans(THD *thd, bool all, bool commit)
       {
         DBUG_ASSERT(cache.cache_log.type != READ_CACHE);
         mysql_mutex_lock(binlog->get_log_lock());
-        error= binlog->write_cache(thd, &cache.cache_log);
+        error= binlog->write_cache_raw(thd, &cache.cache_log);
         mysql_mutex_unlock(binlog->get_log_lock());
       }
     }
@@ -7838,6 +7853,27 @@ int online_alter_savepoint_rollback(THD *thd, LEX_CSTRING name)
   DBUG_RETURN(0);
 }
 
+int Event_log::write_cache_raw(THD *thd, IO_CACHE *cache)
+{
+  DBUG_ENTER("Event_log::write_cache_raw");
+  mysql_mutex_assert_owner(&LOCK_log);
+  if (reinit_io_cache(cache, READ_CACHE, 0, 0, 0))
+    DBUG_RETURN(ER_ERROR_ON_WRITE);
+
+  IO_CACHE *file= get_log_file();
+  IF_DBUG(size_t total= cache->end_of_file,);
+  do
+  {
+    size_t read_len= cache->read_end - cache->read_pos;
+    int res= my_b_safe_write(file, cache->read_pos, read_len);
+    if (unlikely(res))
+      DBUG_RETURN(res);
+    IF_DBUG(total-= read_len,);
+  } while (my_b_fill(cache));
+  DBUG_ASSERT(total == 0);
+  DBUG_RETURN(0);
+}
+
 /*
   Write the contents of a cache to the binary log.
 
diff --git a/sql/log.h b/sql/log.h
index 83e323cb6fbae..81e5243a555c0 100644
--- a/sql/log.h
+++ b/sql/log.h
@@ -403,6 +403,7 @@ class Event_log: public MYSQL_LOG
   void set_write_error(THD *thd, bool is_transactional);
   static bool check_write_error(THD *thd);
   int write_cache(THD *thd, IO_CACHE *cache);
+  int write_cache_raw(THD *thd, IO_CACHE *cache);
   char* get_name() { return name; }
   void cleanup()
   {
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 518671ffdaf89..14db686348007 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -11666,8 +11666,14 @@ static int online_alter_read_from_binlog(THD *thd, rpl_group_info *rgi,
   {
     const auto *descr_event= rgi->rli->relay_log.description_event_for_exec;
     auto *ev= Log_event::read_log_event(log_file, descr_event, false);
-    if (!ev)
+    error= log_file->error;
+    if (unlikely(!ev))
+    {
+      if (error)
+        my_error(ER_IO_READ_ERROR,MYF(0), (ulong)EIO, strerror(EIO), "");
       break;
+    }
+    DBUG_ASSERT(!error);
 
     ev->thd= thd;
     error= ev->apply_event(rgi);
@@ -11680,7 +11686,7 @@ static int online_alter_read_from_binlog(THD *thd, rpl_group_info *rgi,
   } while(!error);
   thd->pop_internal_handler();
 
-  return error;
+  return MY_TEST(error);
 }
 #endif