Re: Proposed patch: make pg_dump --data-only consider FK constraints - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Proposed patch: make pg_dump --data-only consider FK constraints
Date
Msg-id 20080907190448.GD3975@alvh.no-ip.org
Whole thread Raw
In response to Re: Proposed patch: make pg_dump --data-only consider FK constraints  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
Responses Re: Proposed patch: make pg_dump --data-only consider FK constraints  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Heikki Linnakangas wrote:
> Tom Lane wrote:

>> pg_dump: WARNING: circular foreign-key constraints among these table(s):
>> pg_dump:   master
>> pg_dump:   child
>> pg_dump: You may not be able to restore the dump without using --disable-triggers or temporarily dropping the
constraints.
>
> WARNING feels a bit too strong. I realize that that message isn't going  
> to the postmaster's log, bloating it, but if a user does that regularly,  
> always disabling triggers as instructed, or there is in fact never  
> circular references in the data with a particular schema, seeing that  
> big fat warning every time is going to become a bit tiresome. Perhaps  
> "NOTE: ..." ?

But the warning is only going to be emitted if there are actual circular
FK constraints, so it seems OK.

> How about printing that notice at the top of the dump file as well? Most  
> people probably don't look at the dump files, but if someone needs to  
> deal with a data-only dumps that contain circular constraints, and also  
> those that don't, it would be invaluable information.

I assume that this trick will only work at restore time only for custom
or tar dumps.  A text-only dump would produce the warning to stderr at
dump time, no?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.


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