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MDEV-16372 ER_BASE64_DECODE_ERROR upon replaying binary log via mysqlbinlog --verbose

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(This commit is exclusively for 10.2 branch. Do not merge it to 10.3)

In case of a pattern of non-STMT_END-marked Rows-log-event (A) followed by
a STMT_END marked one (B) mysqlbinlog mixes up the base64 encoded rows events
with their pseudo sql representation produced by the verbose option:
      BINLOG '
        base64 encoded data for A
        ### verbose section for A
        base64 encoded data for B
        ### verbose section for B
      '/*!*/;
In effect the produced BINLOG '...' query is not valid and is rejected with the error.
Examples of this way malformed BINLOG could have been found in binlog_row_annotate.result
that gets corrected with the patch.

The issue is fixed with introduction an auxiliary IO_CACHE to hold on the verbose
comments until the terminal STMT_END event is found. The new cache is emptied
out after two pre-existing ones are done at that time.
The correctly produced output now for the above case is as the following:
      BINLOG '
        base64 encoded data for A
        base64 encoded data for B
      '/*!*/;
        ### verbose section for A
        ### verbose section for B

Thanks to Alexey Midenkov for the problem recognition and attempt to tackle,
and to Venkatesh Duggirala who produced a patch for the upstream whose
idea is exploited here, as well as to MDEV-23077 reporter LukeXwang who
also contributed a piece of a patch aiming at this issue.
This commit is contained in:
Andrei Elkin
2020-08-11 21:45:09 +03:00
parent 9bb17ecf43
commit 6112a0f93d
9 changed files with 96 additions and 49 deletions
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11
client/mysqlbinlog.cc
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@@ -891,7 +891,8 @@ static bool print_base64(PRINT_EVENT_INFO *print_event_info, Log_event *ev)
ev->print(result_file, print_event_info);
return
print_event_info->head_cache.error == -1 ||
print_event_info->body_cache.error == -1;
print_event_info->body_cache.error == -1 ||
print_event_info->tail_cache.error == -1;
}
@@ -962,8 +963,12 @@ static bool print_row_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
my_b_printf(body_cache, "'%s\n", print_event_info->delimiter);
// flush cache
if ((copy_event_cache_to_file_and_reinit(&print_event_info->head_cache, result_file) ||
copy_event_cache_to_file_and_reinit(&print_event_info->body_cache, result_file)))
if ((copy_event_cache_to_file_and_reinit(&print_event_info->head_cache,
result_file) ||
copy_event_cache_to_file_and_reinit(&print_event_info->body_cache,
result_file) ||
copy_event_cache_to_file_and_reinit(&print_event_info->tail_cache,
result_file)))
return 1;
}
}