Thread: Help requeted with abend.

Help requeted with abend.

From
"Chris Hoover"
Date:
I just tried to pg_dump a db of mine and recieved the following abend.
Can someone please give me some guidance as to what is going on?  I just
created the db yesturday as part of a db migration plan.

Thanks,

Chris

DB. 7.3.4
OS: RH ES 2.1

Error:
pg_dump: ERROR:  MemoryContextAlloc: invalid request size 4294967293
pg_dump: lost synchronization with server, resetting connection
pg_dump: SQL command to dump the contents of table "detpro2" failed:
PQendcopy() failed.
pg_dump: Error message from server: pg_dump: The command was: COPY
public.detpro2 (column list removed) TO stdout;


Re: Help requeted with abend.

From
Tom Lane
Date:
"Chris Hoover" <revoohc@sermonaudio.com> writes:
> I just tried to pg_dump a db of mine and recieved the following abend.
> Can someone please give me some guidance as to what is going on?  I just
> created the db yesturday as part of a db migration plan.

> pg_dump: ERROR:  MemoryContextAlloc: invalid request size 4294967293

This looks like a corrupted-data problem, specifically a variable-length
field whose length word contains a ridiculous value.

Probably the first thing to do is determine exactly where the bad data
is.  You can eliminate columns if you can select them successfully, and
then home in on the row location by seeing where a "SELECT LIMIT n" fails.
People also sometimes use pg_filedump to look at clobbered data --- if
you search the archives for threads mentioning pg_filedump, you'll find
more detail about this sort of thing than I feel like going into right
now.

It would of course be interesting to find out how the data got
corrupted, but the first step is to gather evidence...

            regards, tom lane