Hi, Vladislav! On Apr 05, Vladislav Vaintroub wrote: > > > > > it'd be nice if you could try os_file_set_atomic_writes() here > > > > to see if that works. > > > > I mean, you can try your function on any other file, not necessarily > > on the tablespace. Even on a temporary file > > Right, but the subtlety here is that test file needs to be on the same > device as ibdata1 tablespace, and figuring out the correct directory is not > trivial . > > Apart from easy default situation, where ibdata lands in the into datadir, > there is innodb_data_home_dir , as well as innodb_data_file_path (this one > needs to be parsed). Not to forget possible symbolic links . Imagine ibdata1 > is placed on atomic-capable filesystem, and symlink to it into datadir. > > So I'd still say this is tricky..
Okay, let's do it your way. If it will cause problems for users we can always reconsider. > > What do you know about it, does one need to sync after > > posix_fallocate()? > > This is a good question, and I do not think I have enough knowledge > to answer that one :) > > note, that fsync() is done anyway almost everywhere after > os_set_file_size() > 1. os_set_file_size during creation single tablespace (file-per-table I > believe) is followed almost immediately by os_file_flush() > 2. os_set_file_size when tablespace is extended, is followed by > fil_flush. > > When innodb starts up for the first time (bootstrap), it is a little > bit different - log file or tablespace are created , > os_set_file_size() is called, and then the file is closed, but not > flushed. My feeling is that it is ok, hoping at least on close() the > metadata will be flushed. And even if not, in case of the probably > worst scenario that machine crashes during bootstrap, - in this case > user data is not lost , as there is no user data yet. Right, and as soon as there are any data there - on any transaction - there will be a flush. > Having said all this, I would not mind to adding an extra fsync() to > the function, if this makes feel safer for someone. I think the > overhead of it would be minimal. No, I think it's fine the way it is. As you didn't remove any fsyncs and InnoDB does sync after resizing, it should be ok. Regards, Sergei _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
