Re: Removing unreferenced files

On 08/05/2015 11:44 AM, Ron Farrer wrote:

> Initial questions that had no consensus in previous discussions:
> 1. Approach on file handling undecided
> 2. Startup vs standalone tool

I think it should be on startup and perhaps also have a function that
will do it from user space. If this problem persists, we shouldn't
expect users to go down to clean it up.

> 3. If startup: how to determine when to run
>
> Outstanding problems (point-for-point with original 2005 post):
> 1. Does not work with non-standard tablespaces. The check will even
> report all files are stale, etc.
> 2. Has issues with stale subdirs of a tablespace (subdirs corresponding
> to a nonexistent database) [appears related to #1 because of maintenance
> mode and not failing]
> 3. Assumes relfilenode is unique database-wide when it’s only safe
> tablespace-wide
> 4. Does not examine table segment files such as “nnn.1” - it should
> instead complain when “nnn” does not match a hash entry
> 5. It loads every value of relfilenode in pg_class into the hash table
> without checking that it is meaningful or not - needs to check.
> 6. strol vs strspn (or other) [not sure what the problem here is. If
> errors are handled correctly this should not be an issue]
> 7. No checks for readdir failure [this should be easy to check for]

Ron,

Do you have suggestions on how to resolve any of the 1-7?

>
> Other thoughts:
> 1. What to do if problem happens during drop table/index and the files
> that should be removed are still there.. the DBA needs to know when this
> happens somehow

Why? If the drop/table/index happens, should it not just remove those files?

> 2. What happened to pgfsck: was that a better approach? why was that
> abandoned?

> 3. What to do about stale files and missing files

IMO, unless there is a prevailing reason not to we should remove them.

JD

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