Horton
Menu

Re: pg_upgrade failing for 200+ million Large Objects

Jan Wieck <jan@wi3ck.info>

View thread
From: Jan Wieck <jan@wi3ck.info>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Bruce Momjian <bruce@momjian.us>, Zhihong Yu <zyu@yugabyte.com>, Andrew Dunstan <andrew@dunslane.net>, Magnus Hagander <magnus@hagander.net>, Robins Tharakan <tharakan@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2021-03-23T19:22:04Z
Lists: pgsql-hackers 
On 3/23/21 2:59 PM, Tom Lane wrote:
> Jan Wieck <jan@wi3ck.info> writes:
>> On 3/23/21 2:35 PM, Tom Lane wrote:
>>> If you're passing multiple options, that is
>>> --pg-dump-options "--foo=x --bar=y"
>>> it seems just horribly fragile.  Lose the double quotes and suddenly
>>> --bar is a separate option to pg_upgrade itself, not part of the argument
>>> for the previous option.  That's pretty easy to do when passing things
>>> through shell scripts, too.
> 
>> ... which would be all really easy if pg_upgrade wouldn't be assembling 
>> a shell script string to pass into parallel_exec_prog() by itself.
> 
> No, what I was worried about is shell script(s) that invoke pg_upgrade
> and have to pass down some of these options through multiple levels of
> option parsing.

The problem here is that pg_upgrade itself is invoking a shell again. It 
is not assembling an array of arguments to pass into exec*(). I'd be a 
happy camper if it did the latter. But as things are we'd have to add 
full shell escapeing for arbitrary strings.

> 
> BTW, it doesn't seem like the "pg-" prefix has any value-add here,
> so maybe "--dump-option" and "--restore-option" would be suitable
> spellings.

Agreed.


Regards, Jan

-- 
Jan Wieck
Principle Database Engineer
Amazon Web Services

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Count individual SQL commands in pg_restore's --transaction-size mode.

  2. Reduce number of commands dumpTableSchema emits for binary upgrade.

  3. Invent --transaction-size option for pg_restore.

  4. Rearrange pg_dump's handling of large objects for better efficiency.

  5. Add temporal PRIMARY KEY and UNIQUE constraints

  6. Fix typo and case in messages