Backend sent D message without prior T

Antonis Antoniou <a.antoniou@albourne.com> writes:

I get the following message:
Backend sent D message without prior T

Does anyone knows about this message? I am expecting to retrieve
2818510 records and am using PostgreSQL 7.1beta4.

IIRC, this is a fairly common symptom of the frontend app running out
of memory --- libpq loses sync with what the backend is sending, and
it doesn't handle that very gracefully.

I'd suggest using a cursor to retrieve the data in more manageable
chunks.

regards, tom lane

Tom Lane wrote:

Antonis Antoniou <a.antoniou@albourne.com> writes:

I get the following message:
Backend sent D message without prior T

Does anyone knows about this message? I am expecting to retrieve
2818510 records and am using PostgreSQL 7.1beta4.

IIRC, this is a fairly common symptom of the frontend app running out
of memory --- libpq loses sync with what the backend is sending, and
it doesn't handle that very gracefully.

I'd suggest using a cursor to retrieve the data in more manageable
chunks.

regards, tom lane

This is strange because the machine has 1GB of memory. Using the same
database on PostgreSQL 7.0.2 and on a machine that has 500MB of memory
the above query works fine.

Regards
Antonis

Antonis Antoniou <a.antoniou@albourne.com> writes:

Tom Lane wrote:

IIRC, this is a fairly common symptom of the frontend app running out
of memory --- libpq loses sync with what the backend is sending, and
it doesn't handle that very gracefully.

This is strange because the machine has 1GB of memory. Using the same
database on PostgreSQL 7.0.2 and on a machine that has 500MB of memory
the above query works fine.

But what do you have the per-process memory limit set to on this
machine? (ulimit, kernel MAXDSIZ parameter, or swap space limits might
be preventing your frontend from using all available memory.)

regards, tom lane