pg_dump error

Started by mikealmost 25 years ago3 messagesgeneral
Jump to latest
#1mike
matrix@quadrent.net

I'm trying to back up a table by dumping to a text file,
but in the proccess of dumping I get the following error

dumpSequence(pilgram_en_id_seq): different sequence name returned by SELECT: pilgram_cross_id_seq

I'm not sure what this means, and I have no idea how to corect it.

Mike

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: mike (#1)
Re: pg_dump error

"mike" <matrix@quadrent.net> writes:

dumpSequence(pilgram_en_id_seq): different sequence name returned by SELECT=
: pilgram_cross_id_seq

I'm not sure what this means, and I have no idea how to corect it.

Looking at the source code, it would seem that pg_dump is unhappy
because "SELECT sequence_name FROM pilgram_en_id_seq" returned
"pilgram_cross_id_seq" instead of the expected "pilgram_en_id_seq".

I'm not sure why exactly pg_dump is bothering to make such a
cross-check, but probably the more interesting question is how the
sequence got that way. Did you rename it at some point?

I find that "ALTER TABLE RENAME" will work without complaint on a
sequence. Seems we should either
(a) prohibit renaming a sequence;
(b) improve ALTER TABLE RENAME to know about changing the
sequence_name field as well;
(c) remove this cross-check from pg_dump; and/or
(d) remove the sequence_name field from sequences entirely.

(c) looks like the path of least resistance. I don't like (d) because
of the risk of breaking existing application code that might look at
the contents of sequences. Comments?

regards, tom lane

#3Gregory Wood
gregw@com-stock.com
In reply to: mike (#1)
Re: pg_dump error

I find that "ALTER TABLE RENAME" will work without complaint on a
sequence. Seems we should either
(a) prohibit renaming a sequence;
(b) improve ALTER TABLE RENAME to know about changing the
sequence_name field as well;
(c) remove this cross-check from pg_dump; and/or
(d) remove the sequence_name field from sequences entirely.

(c) looks like the path of least resistance. I don't like (d) because
of the risk of breaking existing application code that might look at
the contents of sequences. Comments?

I know for a particular program I wrote, I wrote function that you feed it a
tablename and the serial fieldname and it spits back the currval, or the
nextval. I don't foresee renaming these fields or the sequences, but things
change.

It seems like (b) provides the most straightforward and predictable
behavior. Then again, I don't have to code it :)

Greg