Description:
In check_temp_dir(), mysqld creates a temporary file (SQL_LOAD-uuid) to check permission to create a file, with flag O_EXCL.
--------
snprintf(unique_tmp_file_name, size_of_tmp_file_name, "%s%s%s", tmp_file,
channel_name, server_uuid);
if ((fd = mysql_file_create(key_file_misc, unique_tmp_file_name, CREATE_MODE,
O_WRONLY | O_EXCL | O_NOFOLLOW, MYF(MY_WME))) < 0)
return 1;
/*
Clean up.
*/
mysql_file_close(fd, MYF(0));
mysql_file_delete(key_file_misc, unique_tmp_file_name, MYF(0));
my_free(unique_tmp_file_name);
return 0;
and in my_create(), with flag O_CREAT
----------
fd = mysys_priv::RetryOnEintr(
[&]() {
return open(FileName, AccessFlags | O_CREAT,
CreateFlags ? CreateFlags : my_umask);
},
-1);
In POSIX Programmer's Manual, if the file exists, this flag has no effect except as noted under O_EXCL below.
So if the SQL_LOAD-xxx file exists, the SQL thread will report the following error and unable to start again:
Unable to use slave's temporary directory /tmp - Can't create/write to file '/tmp/SQL_LOAD-5a86a661-b7b1-11f0-bc6d-0242ac11000c' (OS errno 17 - File exist)
How to repeat:
stop slave;
create the file SQL_LOAD-uuid in replica_load_tmpdir.
start slave;
Suggested fix:
remove O_EXCL flag when mysql_file_create in check_temp_dir
or
Check to see if the file exists， and delete it before create.
Description: In check_temp_dir(), mysqld creates a temporary file (SQL_LOAD-uuid) to check permission to create a file, with flag O_EXCL. -------- snprintf(unique_tmp_file_name, size_of_tmp_file_name, "%s%s%s", tmp_file, channel_name, server_uuid); if ((fd = mysql_file_create(key_file_misc, unique_tmp_file_name, CREATE_MODE, O_WRONLY | O_EXCL | O_NOFOLLOW, MYF(MY_WME))) < 0) return 1; /* Clean up. */ mysql_file_close(fd, MYF(0)); mysql_file_delete(key_file_misc, unique_tmp_file_name, MYF(0)); my_free(unique_tmp_file_name); return 0; and in my_create(), with flag O_CREAT ---------- fd = mysys_priv::RetryOnEintr( [&]() { return open(FileName, AccessFlags | O_CREAT, CreateFlags ? CreateFlags : my_umask); }, -1); In POSIX Programmer's Manual, if the file exists, this flag has no effect except as noted under O_EXCL below. So if the SQL_LOAD-xxx file exists, the SQL thread will report the following error and unable to start again: Unable to use slave's temporary directory /tmp - Can't create/write to file '/tmp/SQL_LOAD-5a86a661-b7b1-11f0-bc6d-0242ac11000c' (OS errno 17 - File exist) How to repeat: stop slave; create the file SQL_LOAD-uuid in replica_load_tmpdir. start slave; Suggested fix: remove O_EXCL flag when mysql_file_create in check_temp_dir or Check to see if the file exists， and delete it before create.