"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