I am getting the following warning when our program runs pg_dump.exe and the output is in custom format and send to standard out which is connected to a pipe (Windows platform).
pg_dump: [custom archiver] WARNING: ftell mismatch with expected position -- ftell used
The output of pg_dump is received by another process that copies it (and some other data) into a zip file. When I extract the db backup from the zip the backup is fine and I can restore it.
I have both tried the pg_dump.exe from the 9.5 alpha and a stable 9.4 both generate this warning.
When I change the format to plain the warning goes away.
When I call pg_dump from the commandline and let it send to standard out and redirect it to a file the warning does not occur but it does occur when I redirect to nul.
Is there a way to prevent this warning? I would think pg_dump shouldn't call ftell on a pipe.