Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.1.28
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OS: ArchLinux
mariabackup: Patched version with extra debug, based on 10.1 (98cd0ec536915b25a841ffc227285b15f35acef7)
MariaDB: 10.1.28
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10.1.30
Description
Hello
Taking incremental backup like: `mariabackup --backup --incremental-lsn=xx` is way slower than taking a full backup, something like 20x+ as slow.
I did a bit of debugging, and noticed that it spent way longer in xtrabackup_copy_datafile, when doing inc backup (~ 0.02 vs ~ 0.001 (full backup)).
After a bit more trail-and-error, I found that it spent most of the time in a `memset` line. This line: https://github.com/MariaDB/server/blob/da05d0276a0569341c8bb41365dc7b05f9c4ddb7/extra/mariabackup/write_filt.cc#L80
I found that by adding the following print statement to the file: https://github.com/klausenbusk/server/commit/afcdb9128927e714ee0e3bcf5c14fea2f56855e0
Which gave me:
inc: 0.000001
inc: 0.000004
inc: 0.027387
inc: 0.027435
Ideally the code should only write delta file, when something has changed. At the moment it write a lot of "dummy" delta files, which only contain the header.
Regards Kristian Klausen
Attachments
Activity
Reported upstream: https://bugs.launchpad.net/percona-xtrabackup/+bug/1731249
klausenbusk, did you have a chance to look at how it performs for you in 10.1.29, since it already contains a patch that I think would speed up your backup considerably.
Closing due to no feedback. Please feel free to comment, if it did not solve it for you
wlad sorry for the late respond. The fix [1] does indeed fix it, full backup takes around ~ 3 min now and inc backup around ~ 1,5 min.
Many thanks 
I did stumble on a packing issue, when changing my script though: https://jira.mariadb.org/browse/MDEV-15869
[1] https://github.com/MariaDB/server/commit/53c7aaf332d31d0441a533fd9a91b380169ab611
> If making a full backup is not a big deal for you, why not use a binary diff tool, e.g rdiff, instead of this incremental backup
It adds unneeded complexity. I store the backup on object storage services (Backblaze B2 & Amazon S3), so I can't use complex tool without copying a lot of files back and forth.
With mariabackup I only need to push files, with rdiff I would need to pull the files from the last backup <somehow>. It would be much easier if mariabackup could just be fixed.