April 6, 2026 - This incident, known as "fsyncgate", not only revealed an architectural flaw in PostgreSQL itself, but also exposed a deep conflict between the Linux kernel, file systems, and databases regarding I/O error handling.

Fsyncgate: errors on fsync are unrecovarable | Patreon

July 5, 2023 - This article covers the current status, history, and OS and OS version differences relating to the circa 2018 fsync() reliability issues discussed on the PostgreSQL mailing list and elsewhere. It has sometimes been referred to as "fsyncgate 2018".

The so-called “fsyncgate” problem only affects systems that use buffered IO to store data persistently—such as some databases. At its core, the problem is that errors can go unnoticed when they occur while writing changed data back from ...

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December 15, 2023 - But fsyncgate makes me cry inside. It sounds like PostgreSQL made the decision to crash instead of retry forever upon fsync errors (which is the wrong way to do it). But it wasn't their fault, because OSs and filesystems don't always perform correctly when they run out of disk space.

February 16, 2019 - PGCon 2018 fsyncgate : Matthew Wilcox · 昨年のPGConでKernel開発者が発表したlinux kernelのfsyncについての話 · 個人的にもこれはおススメ · https://goo.gl/Qst2Lf · いくつか抜粋。 · Q. どうやって修正パッチをテストした？ ·

July 23, 2019 - The part I found most interesting was here: https://lists.openwall.net/linux-ext4/2018/04/12/8 · where the ext4 maintainer writes:

The Postgres fsyncgate incident: where the Postgres team realised that the guarantees around Linux's fsync syscall weren't as strong as they thought

August 4, 2023 - Five years ago, Craig Ringer, posted this post on the Postgres mailing list to report that he had run into real data loss with Postgres. The critical database guarantee of durability, the D in ACID had been violated. What was more stunning, I think, and perhaps the reason that the incident became known as Fsyncgate is that this wasn't due to a bug in Postgres per se.

March 27, 2023 - This blogpost is about an investigation I performed recently about the fsync() call. If you are... Tagged with linux, performance, hardware, disk.

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February 26, 2019 - Or an early recap of the "fsyncgate" issue in textual form: https://lwn.net/Articles/752063/ · Related (also listed by Tomas Vondra): Linux's IO errors reporting https://youtu.be/74c19hwY2oE

July 18, 2019 - Fsync, as implemented on Linux, has some semantics the Postgres devs found extremely surprising. Email thread: https://danluu.com/fsyncgate/ When I read that email thread I found it surprising, too. This might very well have implications...

1 week ago - A deep dive into PostgreSQL's ... — a 2018 discovery that Linux silently discards dirty pages after writeback failures, marking them clean and reporting the error only once to whichever file descriptor calls fsync() first...

October 8, 2024 - Even though the fsync system call ensures that your data is written to the disk, this command should be handled with caution. Let’s recall the incident called “fsyncgate,” which caused a data loss in PostgreSQL. Both the fsync and retry-on-failure logics were implemented in PostgreSQL, ...

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February 9, 2024 - If anyone remembers fsync-gate https://danluu.com/fsyncgate/ which showed a lot of vulnerabilities in other popular DBMSs, some other research was published on the topic as well https://www.usenix.org/conference/atc20/presentation/rebello

Fsyncgate affected most DBMSs. Postgres merely illuminated it. But see the patches by MySQL, SQLite, WiredTiger and others applied at the time (albeit incorrectly).

The thing I took from fsyncgate is that we once understood "some set of writes" to be "every write ever made that has not been written out yet", and then we found out that the set is rather smaller: only writes since the last fsync() call, and perhaps, only ones made on file descriptors that were open when fsync() is called.