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Comments - Migrating from 'innodb' checksum to 'crc32' checksum

10 months, 1 week ago Keshan Nageswaran
Re: Migrating from 'innodb' checksum to 'crc32' checksum
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Thank you for the detailed explanation.

The issue that I am facing right now. I am trying to upgrade MariaDB from 10.4.10 to 10.11.4. The checksum algorithm used in 10.4.10 is innodb. The checksum we are trying to use in 10.11.4 is full_crc32. We take physical backups in 10.4.10. The restore process includes innochecksum utility to compare checksums generated with stored checksums to identify any damages to data pages.

When I try to restore the backup taken in 10.4.10 with innodb checksum to MariaDB 10.11.4 with full_crc32 checksum. Checksum comparison fails for each innodb tables in my database at the first page complaining as following; 

{
Fail: page::0 invalid
Exceeded the maximum allowed checksum mismatch count::1 current::0
Error: Page 0 checksum mismatch, can't continue.
}

As mentioned previously we use innochecksum utility to make this comparison. The initial understanding is that innochecksum utility has removed deprecated checksum algorithms from use (innnodb, none). Hence, it will not be supported. MDEV-25105

Then we decided to migrate the checksum algorithm to a algorithm(crc32) supported in innochecksum utility and take backups. Hence, we tried migrating MariaDB 10.4.10 to crc32 first so the physical backups taken would be compatible with MariaDB 10.11.4 if we use crc32/full_crc32 algorithm.

My followup questions;

  • Ideal scenario that I would like to achieve is to use 10.4.10 backups in 10.11.4 with the migrated checksum algorithm (innodb->full_crc32). How can I achieve it?
  • I had the same understanding as you mentioned that no change required. What could be the reason for the failure during checksum validation at first page?
  • Is it because mismatch of checksum algorithms used (backup has innodb and validating server has crc32/full_crc32 assigned in configuration) ?
  • In that case, what is recommended? How we can check for integrity of data during restore?
  • how can I rebuild all innodb tables during migration of innodb_checksum_algorithm configuration to have all blocks updated and not wait until it gets updated over time?
 
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