Horton

Re: pg11+: pg_ls_*dir LIMIT 1: temporary files .. not closed at end-of-transaction

Fabien COELHO <coelho@cri.ensmp.fr>

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From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@postgresql.org, Alvaro Herrera <alvherre@2ndquadrant.com>, David Steele <david@pgmasters.net>, "Bossart, Nathan" <bossartn@amazon.com>, Thomas Munro <thomas.munro@gmail.com>
Date: 2020-03-31T05:36:03Z
Lists: pgsql-hackers 
Hello,

>> As I wrote about an earlier version of the patch, ISTM that instead of
>> reinventing, extending, adapting various ls variants (with/without
>> metadata, which show only files, which shows target of links, which shows
>> directory, etc.) we would just need *one* postgres "ls" implementation
>> which would be like "ls -la arg" (returns file type, dates), and then
>> everything else is a wrapper around that with appropriate filtering that
>> can be done at the SQL level, like you started with recurse.
>
> Yeah, I agree that some new function that can represent symlinks
> explicitly in its output is the place to deal with this, for
> people who want to deal with it.
>
> In the meantime, there's still the question of what pg_ls_dir_files
> should do exactly.  Are we content to have it ignore symlinks?
> I remain inclined to think that's the right thing given its current
> brief.

My 0.02€:

I agree that it is enough to reproduce the current behavior of various 
existing pg_ls* functions, but on the other hand outputing a column type 
char like ls (-, d, l…) looks like really no big deal. I'd say that the 
only reason not to do it may be to pass this before feature freeze.

-- 
Fabien.

Commits

  1. Teach pg_ls_dir_files() to ignore ENOENT failures from stat().

  2. Remove useless pfree()s at the ends of various ValuePerCall SRFs.

  3. Avoid holding a directory FD open across assorted SRF calls.

  4. Document pg_ls_*dir hiding of directories and special files

  5. Avoid holding a directory FD open across pg_ls_dir_files() calls.

  6. Adjust nodeFunctionscan.c to reset transient memory context between calls