Re: Accidental removal of a file causing various problems

On 2018-Aug-25, Pavan Deolasee wrote:

> The errors were simply about about the missing file. See attached
> reproduction script that I created while studying this complaint. It will
> throw errors such as:
>
> psql: FATAL: could not open file "base/12669/16387": No such file or
> directory
> CONTEXT: writing block 207724 of relation base/12669/16387
>
> Now of course, the file is really missing. But the user was quite surprised
> that they couldn't connect to any database, even though mishap happened to
> a user table in one of their reporting databases.

Hmm, that sounds like there's a bunch of dirty pages waiting to be
written to that nonexistant file, and the error prevents the starting
backend from acquiring a free page on which to read something from disk
for another relation.

> To add to their misery, while restart fixed this error and opened
> their other databases for regular operation, it caused the toast
> corruption.

Sounds like the right data was in shared buffers, but it was lost in the
shutdown.

--
Álvaro Herrera https://www.2ndQuadrant.com/
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