On Thu, Dec 8, 2022 at 7:28 PM Reindl Harald <[email protected]> wrote:
> >>>> MariaDB Server 10.4 introduced a new file format > >>>> innodb_checksum_algorithm=full_crc32, and MariaDB Server 10.5 made it > >>>> the default. Any files that were created when that setting is active > >>>> are guaranteed to write any unused bytes as zeroes. It also fixes a > >>>> peculiar design decision that some bytes of the page are not covered > >>>> by any checksum, and that a page is considered valid if any of the > >>>> non-full_crc32 checksums happen to produce a match. This includes the > >>>> magic 0xdeadbeef for innodb_checksum_algorithm=none. > >>>> > >>>> Maybe we should consider eventually deprecating write support for the > >>>> non-full_crc32 format, to force a fresh start. > >>> > >>> Please don't. Some of us run MariaDB on file systems that do their own > >>> block checksumming, and thus run innodb_checksum_algorithm=none > >> > >> that's nonsense - when mariadb writes wrong data in it's files no > >> filesystem can magically fix that > > > > MariaDB can't fix it either. And if that is what happened, there is no > > benefit to duplicating the effort. > > MariaDB does the same as the filesystem > InnoDB in fact is more ore less a FS on top of a FS So why do it at both levels? And what makes doing it at MariaDB level in any way better than doing it somewhere else? > >> you need to understand what innodb checksums are and then it's logical > >> that the file-system layer is a completly different world > >> > >> https://dba.stackexchange.com/questions/171708/what-is-an-innodb-page-checksum > > > > You need to understand that properly thought out and sensibly written > > file systems (which is, granted, pretty rare, I know of a total of 1) > > implicitly prevent torn pages from being possible. > > So the checksum and the doublewrite are completely redundant in such > > cases, and can be safely disabled. > > "Some of us run MariaDB on file systems that do their own block > checksumming, and thus run innodb_checksum_algorithm=none" makes you > looking like a fool - period > > are you dumb or why don't you understand that the filesystem is a > completly different layer and has no clue about the data itself? Are you too dumb to understand that if a block is corrupted at InnoDB level MariaDB can't do anyting to fix it, but if a block is corrupted at lower level, ZFS can fix it from redundantly stored data and MariaDB never gets to ingest a corrupted block in the first place? If you disagree, please describe a scenario in which an InnoDB page checksum does anything useful if the file system it is on has built in block checksumming and data redundancy. _______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp
