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PostgreSQL Support for Certificate Transparency Logs Now Available

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Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#11
post #7
post #3

> a CT log failure earlier this year due to MariaDB corruption after disk space exhaustion provided the motivation for a change.

That seems like a rather serious bug. Disappointing there's not more follow up with MariaDB

They know about the problem but appear uninterested in improving the situation: https://mariadb.com/kb/en/database-corruption-and-data-loss-...

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#12
post #7

Earlier quoted context omitted.

That seems like a rather serious bug. Disappointing there's not more follow up with MariaDB

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

> If you let a disk run full weird shit happens.

Only in buggy software that ignores errors from system calls.

Obviously you can expect availability problems when you run out of space, but there's no excuse for losing data from committed transactions given that the OS will reliably report the error.

> So I do strongly hope that besides changing software, they added some disk space monitoring.

One of the action items in their incident report was improving monitoring and alerting: https://groups.google.com/a/chromium.org/g/ct-policy/c/038B7...

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#13
post #7

Earlier quoted context omitted.

That seems like a rather serious bug. Disappointing there's not more follow up with MariaDB

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

Bad things can happen when your disk is full, but "the whole table is now lost beyond repair" is not reasonable for a database.

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#14
post #11
post #7

Earlier quoted context omitted.

That seems like a rather serious bug. Disappointing there's not more follow up with MariaDB

They know about the problem but appear uninterested in improving the situation: https://mariadb.com/kb/en/database-corruption-and-data-loss-...

I don't really think your link supports that conclusion.

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#15
post #12

Earlier quoted context omitted.

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

> If you let a disk run full weird shit happens. Only in buggy software that ignores errors from system calls. Obviously you can expect availability problems when you run out of space, but there's no excuse for losing data from committed transactions given that the OS will reliably report the error. > So I do strongly hope that besides changing software, they added some disk space monitoring. One of the action items…

Keep in mind the report doesn't mention what MariaDB version was being used, nor what storage engine. The description in the incident report simply doesn't align with how InnoDB behaves, at all. (InnoDB is the default storage engine in MariaDB and MySQL, and by far the most widely used storage engine in these DBs.)

For example, the author says "Whilst its primary key index still includes the ~1,300 unsequenced rows, the table itself no longer contains them." This is simply impossible in InnoDB, which uses a clustered index – the primary key B-tree literally is the table with InnoDB's design. The statement in the incident report is complete nonsense.

Also if the storage volume runs out of space, InnoDB rolls back the statement and returns an error. See https://dev.mysql.com/doc/refman/5.7/en/innodb-error-handlin... (MySQL 5.7 doc, but this also aligns with MariaDB's behavior for this situation)

So maybe they were using MyISAM, which is ancient and infamously non-crash-safe and should pretty much never be used for anything of consequence, which has been well-known in the database world for 15+ years. Who knows, they didn't say.

The report directly says "Our teams have very little expertise with MySQL/MariaDB", which also makes me question their conclusion "that it is not possible" to restore/recover.

Also this whole incident happened to Sectigo, take from that what you will.

The one thing I'd criticize MariaDB for here is that they're lacking an additional safety mechanism which MySQL has: by default MySQL will shut down the database server if a write to the binary log cannot be successfully made, ensuring that any writes on the primary can be replicated as well. (iirc this was a contribution from Facebook.)

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#16
post #13

Earlier quoted context omitted.

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

Bad things can happen when your disk is full, but "the whole table is now lost beyond repair" is not reasonable for a database.

Completely agreed, but "the whole table is now lost beyond repair" is simply not how InnoDB behaves, at all! So the whole incident report is quite fishy. See my reply to the sibling comment.

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#17
> However, a CT log failure earlier this year due to MariaDB corruption after disk space exhaustion provided the motivation for a change. PostgreSQL, with its robust Write-ahead Logging (WAL) and strict adherence to ACID (Atomicity, Consistency, Isolation, Durability) principles, made it a better option for avoiding corruption and improving data integrity of the log.

This sounds incredibly suspicious to me. I wonder which storage engine they were using or if there was any unusual configuration that contributed to this issue.

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#18
post #12

Earlier quoted context omitted.

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

> If you let a disk run full weird shit happens. Only in buggy software that ignores errors from system calls. Obviously you can expect availability problems when you run out of space, but there's no excuse for losing data from committed transactions given that the OS will reliably report the error. > So I do strongly hope that besides changing software, they added some disk space monitoring. One of the action items…

> Only in buggy software that ignores errors from system calls.

Is there any reason to conclude that is what happened?

Re: PostgreSQL Support for Certificate Transparency Logs Now Available

#20
post #12

Earlier quoted context omitted.

If you let a disk run full weird shit happens. But it reads to me as _we_, not mariadb, made a big oopsie and TADA \o/ now we change software. So I do strongly hope that besides changing software, they added some disk space monitoring.

> If you let a disk run full weird shit happens. Only in buggy software that ignores errors from system calls. Obviously you can expect availability problems when you run out of space, but there's no excuse for losing data from committed transactions given that the OS will reliably report the error. > So I do strongly hope that besides changing software, they added some disk space monitoring. One of the action items…

Please enlighten me with some software examples that are free of bugs :)
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